import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
 
@SpringBootApplication
public class SpringBootCrudRestfulApplication {
 
    public static void main(String[] args) {
        SpringApplication.run(SpringBootCrudRestfulApplication.class, args);
    }
}

public class Employee {
 
    private String empNo;
    private String empName;
    private String position;
 
    public Employee() { }
 
    public Employee(String empNo, String empName, String position) {
        this.empNo = empNo;
        this.empName = empName;
        this.position = position;
    }
 
    public String getEmpNo() {
        return empNo;
    }
 
    public void setEmpNo(String empNo) {
        this.empNo = empNo;
    }
 
    public String getEmpName() {
        return empName;
    }
 
    public void setEmpName(String empName) {
        this.empName = empName;
    }
 
    public String getPosition() {
        return position;
    }
 
    public void setPosition(String position) {
        this.position = position;
    }
 
}

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
 
import org.springexample.sbcrudrestful.model.Employee;
import org.springframework.stereotype.Repository;
 
@Repository
public class EmployeeDAO {
 
    private static final Map<String, Employee> empMap = new HashMap<String, Employee>();
 
    static {
        initEmps();
    }
 
    private static void initEmps() {
        Employee emp1 = new Employee("E01", "Smith", "Clerk");
        Employee emp2 = new Employee("E02", "Allen", "Salesman");
        Employee emp3 = new Employee("E03", "Jones", "Manager");
 
        empMap.put(emp1.getEmpNo(), emp1);
        empMap.put(emp2.getEmpNo(), emp2);
        empMap.put(emp3.getEmpNo(), emp3);
    }
 
    public Employee getEmployee(String empNo) {
        return empMap.get(empNo);
    }
 
    public Employee addEmployee(Employee emp) {
        empMap.put(emp.getEmpNo(), emp);
        return emp;
    }
 
    public Employee updateEmployee(Employee emp) {
        empMap.put(emp.getEmpNo(), emp);
        return emp;
    }
 
    public void deleteEmployee(String empNo) {
        empMap.remove(empNo);
    }
 
    public List<Employee> getAllEmployees() {
        Collection<Employee> c = empMap.values();
        List<Employee> list = new ArrayList<Employee>();
        list.addAll(c);
        return list;
    }
 
}

import java.util.List;
 
import org.springexample.sbcrudrestful.dao.EmployeeDAO;
import org.springexample.sbcrudrestful.model.Employee;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
 
@RestController
public class MainRESTController {
 
    @Autowired
    private EmployeeDAO employeeDAO;
 
    @RequestMapping("/")
    @ResponseBody
    public String welcome() {
        return "Welcome to RestTemplate Example.";
    }
 
    @RequestMapping(value = "/employees", //
            method = RequestMethod.GET, //
            produces = { MediaType.APPLICATION_JSON_VALUE, //
                    MediaType.APPLICATION_XML_VALUE })
    @ResponseBody
    public List<Employee> getEmployees() {
        List<Employee> list = employeeDAO.getAllEmployees();
        return list;
    }
 
    @RequestMapping(value = "/employee/{empNo}", //
            method = RequestMethod.GET, //
            produces = { MediaType.APPLICATION_JSON_VALUE, //
                    MediaType.APPLICATION_XML_VALUE })
    @ResponseBody
    public Employee getEmployee(@PathVariable("empNo") String empNo) {
        return employeeDAO.getEmployee(empNo);
    }
 
    @RequestMapping(value = "/employee", //
            method = RequestMethod.POST, //
            produces = { MediaType.APPLICATION_JSON_VALUE, //
                    MediaType.APPLICATION_XML_VALUE })
    @ResponseBody
    public Employee addEmployee(@RequestBody Employee emp) {
 
        System.out.println("(Service Side) Creating employee: " + emp.getEmpNo());

        return employeeDAO.addEmployee(emp);
    }
 
    @RequestMapping(value = "/employee", //
            method = RequestMethod.PUT, //
            produces = { MediaType.APPLICATION_JSON_VALUE, //
                    MediaType.APPLICATION_XML_VALUE })
    @ResponseBody
    public Employee updateEmployee(@RequestBody Employee emp) {
 
        System.out.println("(Service Side) Editing employee: " + emp.getEmpNo());
 
        return employeeDAO.updateEmployee(emp);
    }
 
    @RequestMapping(value = "/employee/{empNo}", //
            method = RequestMethod.DELETE, //
            produces = { MediaType.APPLICATION_JSON_VALUE, MediaType.APPLICATION_XML_VALUE })
    @ResponseBody
    public void deleteEmployee(@PathVariable("empNo") String empNo) {
 
        System.out.println("(Service Side) Deleting employee: " + empNo);
 
        employeeDAO.deleteEmployee(empNo);
    }
}

// Get all the employees details
http://localhost:8080/employees
http://localhost:8080/employees.json
http://localhost:8080/employees.xml


// Get the employee based in employee-id
http://localhost:8080/employee/E01
http://localhost:8080/employee/E01.xml
http://localhost:8080/employee/E01.json

spring.datasource.url=jdbc:mysql://localhost:3306/springbootdb  
spring.datasource.username=root  
spring.datasource.password=mysql  
spring.jpa.hibernate.ddl-auto=create-drop  

package com.learningzone;  

import org.springframework.boot.SpringApplication;  
import org.springframework.boot.autoconfigure.SpringBootApplication;  
@SpringBootApplication  
public class SpringBootJdbcApplication {  
    public static void main(String[] args) {  
        SpringApplication.run(SpringBootJdbcApplication.class, args);  
    }  
}

package com.learningzone;
  
import org.springframework.web.bind.annotation.RequestMapping;  
import org.springframework.beans.factory.annotation.Autowired;  
import org.springframework.jdbc.core.JdbcTemplate;  
import org.springframework.web.bind.annotation.RestController;  
@RestController  
public class SpringBootJdbcController {  
    @Autowired  
    JdbcTemplate jdbc;
    @RequestMapping("/insert")  
    public String index(){  
        jdbc.execute("insert into user(name, email) values('Pradeep Kumar','[email protected]')");  
        return "Record inserted Successfully";  
    }  
}  

#src/main/resources/application.properties

## MULTIPART (MultipartProperties)
# Enable multipart uploads
spring.servlet.multipart.enabled=true
# Threshold after which files are written to disk.
spring.servlet.multipart.file-size-threshold=2KB
# Max file size.
spring.servlet.multipart.max-file-size=200MB
# Max Request Size
spring.servlet.multipart.max-request-size=215MB

## File Storage Properties
# All files uploaded through the REST API will be stored in this directory
file.upload-dir=/Users/files/uploads

package com.example.filedemo.property;

import org.springframework.boot.context.properties.ConfigurationProperties;

@ConfigurationProperties(prefix = "file")
public class FileStorageProperties {
    private String uploadDir;

    public String getUploadDir() {
        return uploadDir;
    }

    public void setUploadDir(String uploadDir) {
        this.uploadDir = uploadDir;
    }
}

/* src/main/java/com/example/filedemo/FileDemoApplication.java */
package com.example.filedemo;

import com.example.filedemo.property.FileStorageProperties;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.properties.EnableConfigurationProperties;

@SpringBootApplication
@EnableConfigurationProperties({
        FileStorageProperties.class
})
public class FileDemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(FileDemoApplication.class, args);
    }
}

package com.example.filedemo.controller;

import com.example.filedemo.payload.UploadFileResponse;
import com.example.filedemo.service.FileStorageService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.Resource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.servlet.support.ServletUriComponentsBuilder;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

@RestController
public class FileController {

    private static final Logger logger = LoggerFactory.getLogger(FileController.class);

    @Autowired
    private FileStorageService fileStorageService;
    
    @PostMapping("/uploadFile")
    public UploadFileResponse uploadFile(@RequestParam("file") MultipartFile file) {
        String fileName = fileStorageService.storeFile(file);

        String fileDownloadUri = ServletUriComponentsBuilder.fromCurrentContextPath()
                .path("/downloadFile/")
                .path(fileName)
                .toUriString();

        return new UploadFileResponse(fileName, fileDownloadUri,
                file.getContentType(), file.getSize());
    }

    @PostMapping("/uploadMultipleFiles")
    public List<UploadFileResponse> uploadMultipleFiles(@RequestParam("files") MultipartFile[] files) {
        return Arrays.asList(files)
                .stream()
                .map(file -> uploadFile(file))
                .collect(Collectors.toList());
    }

    @GetMapping("/downloadFile/{fileName:.+}")
    public ResponseEntity<Resource> downloadFile(@PathVariable String fileName, HttpServletRequest request) {
        // Load file as Resource
        Resource resource = fileStorageService.loadFileAsResource(fileName);

        // Try to determine file's content type
        String contentType = null;
        try {
            contentType = request.getServletContext().getMimeType(resource.getFile().getAbsolutePath());
        } catch (IOException ex) {
            logger.info("Could not determine file type.");
        }

        // Fallback to the default content type if type could not be determined
        if(contentType == null) {
            contentType = "application/octet-stream";
        }

        return ResponseEntity.ok()
                .contentType(MediaType.parseMediaType(contentType))
                .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + resource.getFilename() + "\"")
                .body(resource);
    }
}

package com.example.filedemo.payload;

public class UploadFileResponse {
    private String fileName;
    private String fileDownloadUri;
    private String fileType;
    private long size;

    public UploadFileResponse(String fileName, String fileDownloadUri, String fileType, long size) {
        this.fileName = fileName;
        this.fileDownloadUri = fileDownloadUri;
        this.fileType = fileType;
        this.size = size;
    }

	// Getters and Setters (Omitted for brevity)
}

package com.example.filedemo.service;

import com.example.filedemo.exception.FileStorageException;
import com.example.filedemo.exception.CustomFileNotFoundException;
import com.example.filedemo.property.FileStorageProperties;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.Resource;
import org.springframework.core.io.UrlResource;
import org.springframework.stereotype.Service;
import org.springframework.util.StringUtils;
import org.springframework.web.multipart.MultipartFile;
import java.io.IOException;
import java.net.MalformedURLException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardCopyOption;

@Service
public class FileStorageService {

    private final Path fileStorageLocation;

    @Autowired
    public FileStorageService(FileStorageProperties fileStorageProperties) {
        this.fileStorageLocation = Paths.get(fileStorageProperties.getUploadDir())
                .toAbsolutePath().normalize();

        try {
            Files.createDirectories(this.fileStorageLocation);
        } catch (Exception ex) {
            throw new FileStorageException("Could not create the directory where the uploaded files will be stored.", ex);
        }
    }

    public String storeFile(MultipartFile file) {
        // Normalize file name
        String fileName = StringUtils.cleanPath(file.getOriginalFilename());

        try {
            // Check if the file's name contains invalid characters
            if(fileName.contains("..")) {
                throw new FileStorageException("Sorry! Filename contains invalid path sequence " + fileName);
            }

            // Copy file to the target location (Replacing existing file with the same name)
            Path targetLocation = this.fileStorageLocation.resolve(fileName);
            Files.copy(file.getInputStream(), targetLocation, StandardCopyOption.REPLACE_EXISTING);

            return fileName;
        } catch (IOException ex) {
            throw new FileStorageException("Could not store file " + fileName + ". Please try again!", ex);
        }
    }

    public Resource loadFileAsResource(String fileName) {
        try {
            Path filePath = this.fileStorageLocation.resolve(fileName).normalize();
            Resource resource = new UrlResource(filePath.toUri());
            if(resource.exists()) {
                return resource;
            } else {
                throw new CustomFileNotFoundException("File not found " + fileName);
            }
        } catch (MalformedURLException ex) {
            throw new CustomFileNotFoundException("File not found " + fileName, ex);
        }
    }
}

package com.example.filedemo.exception;

public class FileStorageException extends RuntimeException {
    public FileStorageException(String message) {
        super(message);
    }

    public FileStorageException(String message, Throwable cause) {
        super(message, cause);
    }
}

package com.example.filedemo.exception;

import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.ResponseStatus;

@ResponseStatus(HttpStatus.NOT_FOUND)
public class CustomFileNotFoundException extends RuntimeException {
    public CustomFileNotFoundException(String message) {
        super(message);
    }

    public CustomFileNotFoundException(String message, Throwable cause) {
        super(message, cause);
    }
}

mvn spring-boot:run

spring.mail.host=smtp.gmail.com
spring.mail.port=587
spring.mail.username=pradeep.vwa@gmail.com
spring.mail.password=*****

# Other properties
spring.mail.properties.mail.smtp.auth=true
spring.mail.properties.mail.smtp.connectiontimeout=5000
spring.mail.properties.mail.smtp.timeout=5000
spring.mail.properties.mail.smtp.writetimeout=5000

# TLS , port 587
spring.mail.properties.mail.smtp.starttls.enable=true

# SSL, post 465
#spring.mail.properties.mail.smtp.socketFactory.port = 465
#spring.mail.properties.mail.smtp.socketFactory.class = javax.net.ssl.SSLSocketFactory

package com.springtutorial;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.core.io.ClassPathResource;
import org.springframework.mail.SimpleMailMessage;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.mail.javamail.MimeMessageHelper;

import javax.mail.MessagingException;
import javax.mail.internet.MimeMessage;
import java.io.IOException;

@SpringBootApplication
public class Application implements CommandLineRunner {

    @Autowired
    private JavaMailSender javaMailSender;

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

    @Override
    public void run(String... args) {

        System.out.println("Sending Email...");
        try {
            sendEmail();
            //sendEmailWithAttachment();

        } catch (MessagingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        System.out.println("Done");
    }

    void sendEmail() {

        SimpleMailMessage msg = new SimpleMailMessage();
        msg.setTo("[email protected]", "[email protected]");
        msg.setSubject("Testing from Spring Boot");
        msg.setText("Hello World \n Spring Boot Email");

        javaMailSender.send(msg);
    }

    void sendEmailWithAttachment() throws MessagingException, IOException {

        MimeMessage msg = javaMailSender.createMimeMessage();

        // true = multipart message
        MimeMessageHelper helper = new MimeMessageHelper(msg, true);
        helper.setTo("[email protected]");
        helper.setSubject("Testing from Spring Boot");
        helper.setText("<h1>Check attachment for image!</h1>", true);
        helper.addAttachment("my_photo.png", new ClassPathResource("android.png"));

        javaMailSender.send(msg);
    }
}

@Component
// This statement is redundant - singleton is default scope
@Scope("singleton")  // This statement is redundant
public class BeanClass {
 
}

@Component
@Scope("prototype")
public class BeanClass {
}

@Component
@Scope("request")
public class BeanClass {
}
 
// or
 
@Component
@RequestScope
public class BeanClass {
}

@Component
@Scope("session")
public class BeanClass {
}
 
// or
 
@Component
@SessionScope
public class BeanClass {
}

@Component
@Scope("application")
public class BeanClass {
}
 
// or
 
@Component
@ApplicationScope
public class BeanClass {
}

@Component
@Scope("websocket")
public class BeanClass {
}

/**
* AOP program to illustrate types of Advices
*
*// 
@Aspect
class Logging { 
    
    // **Before** 
    @Before("execution(public void com.aspect.ImplementAspect.aspectCall())") 
    public void loggingAdvice1() { 
        System.out.println("Before advice is executed"); 
    } 
  
    // **After** 
    @After("execution(public void com.aspect.ImplementAspect.aspectCall())") 
    public void loggingAdvice2() { 
        System.out.println("Running After Advice."); 
    } 
  
    // **Around** 
    @Around("execution(public void com.aspect.ImplementAspect.myMethod())") 
    public void loggingAdvice3() { 
        System.out.println("Before and After invoking method myMethod"); 
    } 
  
    // **AfterThrowing** 
    @AfterThrowing("execution(" public void com.aspect.ImplementAspect.aspectCall())") 
    public void loggingAdvice4() { 
        System.out.println("Exception thrown in method"); 
    } 
  
    // **AfterRunning** 
    @AfterReturning("execution(public void com.aspect.ImplementAspect.myMethod())") 
    public void loggingAdvice5() { 
        System.out.println("AfterReturning advice is run"); 
    } 
}

/**
* AOP program to illustrate JoinPoints
*
**/
  
@Aspect
class Logging { 
  
    // Passing a JoinPoint Object into parameters of the method 
    // with the annotated advice enables to print the information 
  
    @Before("execution(public void com.aspect.ImplementAspect.aspectCall())") 
    public void loggingAdvice1(JoinPoint joinpoint) { 
        System.out.println("Before advice is executed"); 
        System.out.println(joinpoint.toString()); 
    } 
} 

/**
* AOP program to illustrate PointCuts 
*
**/
@Aspect
class Logging { 

    @Pointcut("execution(public void com.aspect.ImplementAspect.aspectCall())") 
    public void pointCut() { 
    } 
  
    // pointcut() is used to avoid repeatition of code 
    @Before("pointcut()") 
    public void loggingAdvice1() { 
        System.out.println("Before advice is executed"); 
    } 
} 

@Component
public @interface Service {
    ….
}

@Configuration
@EnableOAuth2Sso
public class UiSecurityConfig extends WebSecurityConfigurerAdapter {
     
    @Override
    public void configure(HttpSecurity http) throws Exception {
        http.antMatcher("/**")
          .authorizeRequests()
          .antMatchers("/", "/login**")
          .permitAll()
          .anyRequest()
          .authenticated();
    }
}

@SpringBootApplication
@EnableResourceServer
public class AuthorizationServerApplication extends SpringBootServletInitializer {
    public static void main(String[] args) {
        SpringApplication.run(AuthorizationServerApplication.class, args);
    }
}

@Configuration
@Order(1)
public class SecurityConfig extends WebSecurityConfigurerAdapter {
 
    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.requestMatchers()
          .antMatchers("/login", "/oauth/authorize")
          .and()
          .authorizeRequests()
          .anyRequest().authenticated()
          .and()
          .formLogin().permitAll();
    }
 
    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        auth.inMemoryAuthentication()
            .withUser("john")
            .password(passwordEncoder().encode("123"))
            .roles("USER");
    }
     
    @Bean
    public BCryptPasswordEncoder passwordEncoder(){ 
        return new BCryptPasswordEncoder(); 
    }
}

@RestController
public class UserController {
    @GetMapping("/user/me")
    public Principal user(Principal principal) {
        return principal;
    }
}

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.RestController;

@RestController
@EnableAutoConfiguration
@SpringBootApplication
public class SpringBootHelloWorldApplication {

	public static void main(String[] args) {
		SpringApplication.run(SpringBootHelloWorldApplication.class, args);
	}
}

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class Employee {
	@GeneratedValue(strategy = GenerationType.AUTO)
	@Id
	private long id;

	private String name;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getDept() {
		return dept;
	}

	public void setDept(String dept) {
		this.dept = dept;
	}

	private String dept;

	@Override
	public String toString() {
		return "Employee [id=" + id + ", name=" + name + ", dept=" + dept + "]";
	}
}

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;

import com.springexample.data.EmployeeRepository;
import com.springexample.model.Employee;

@Controller
public class EmployeeController {

	@Autowired
	private EmployeeRepository employeeData;

	@RequestMapping(value = "/addNewEmployee.html", method = RequestMethod.POST)
	public String newEmployee(Employee employee) {
		employeeData.save(employee);
		return ("redirect:/list.html");
	}

	@RequestMapping(value = "/addNewEmployee.html", method = RequestMethod.GET)
	public ModelAndView addNewEmployee() {
		Employee emp = new Employee();
		return new ModelAndView("newEmployee", "form", emp);
	}

	@RequestMapping(value = "/listEmployees.html", method = RequestMethod.GET)
	public ModelAndView employees() {
		List<Employee> allEmployees = employeeData.findAll();
		return new ModelAndView("allEmployees", "employees", allEmployees);
	}
}

spring.mvc.view.prefix:/WEB-INF/jsp/
spring.mvc.view.suffix:.jsp

spring.datasource.url=jdbc:h2:file:./DB
spring.jpa.properties.hibernate.hbm2ddl.auto=update

import org.springframework.web.bind.annotation.RestController;  
@RestController  // using @RestController annotation  
public class HomeController {  
    // controller body  
}  

import org.springframework.web.bind.annotation.RequestMapping;  
import org.springframework.web.bind.annotation.RestController;  
@RestController  
public class HomeController {  
    @RequestMapping(value = "/index", method = "GET")  
    public String index() {  
        return "Dashboard Page!";  
    }  
}  

@GetMapping("/api/foos")
@ResponseBody
public String getFoos(@RequestParam String id) {
    return "ID: " + id;
}

http://localhost:8080/api/foos?id=abc
----
ID: abc

@PostMapping("/api/foos")
@ResponseBody
public String addFoo(@RequestParam(name = "id") String fooId, @RequestParam String name) { 
    return "ID: " + fooId + " Name: " + name;
}

@GetMapping("/api/foos")
@ResponseBody
public String getFoos(@RequestParam(required = false) String id) { 
    return "ID: " + id;
}

http://localhost:8080/api/foos?id=abc
----
ID: abc


http://localhost:8080/api/foos
----
ID: null

@GetMapping("/api/foos")
@ResponseBody
public String getFoos(@RequestParam(defaultValue = "test") String id) {
    return "ID: " + id;
}

http://localhost:8080/api/foos
----
ID: test


http://localhost:8080/api/foos?id=abc
----
ID: abc

@PostMapping("/api/foos")
@ResponseBody
public String updateFoos(@RequestParam Map<String,String> allParams) {
    return "Parameters are " + allParams.entrySet();
}

curl -X POST -F 'name=abc' -F 'id=123' http://localhost:8080/api/foos
-----
Parameters are {[name=abc], [id=123]}

@GetMapping("/api/foos")
@ResponseBody
public String getFoos(@RequestParam List<String> id) {
    return "IDs are " + id;
}

http://localhost:8080/api/foos?id=1,2,3
----
IDs are [1,2,3]

http://localhost:8080/api/foos?id=1&id=2
----
IDs are [1,2]

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes=PaymentConfiguration.class)
public class PaymentServiceTests {

  @Autowired
  private PaymentService paymentService;

  @Test
  public void testPaymentService() {
      // code to test PaymentService class
  }
}

@Controller
@RequestMapping("/post")
public class ExamplePostController {
 
    @Autowired
    ExampleService exampleService;
 
    @PostMapping("/response")
    @ResponseBody
    public ResponseTransfer postResponseController(
      @RequestBody LoginForm loginForm) {
        return new ResponseTransfer("Thanks For Posting!!!");
     }
}

{"text":"Thanks For Posting!!!"}

import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class MyController {

    @RequestMapping(path="/{name}/{age}")
    public String getMessage(@PathVariable("name") String name, 
            @PathVariable("age") String age) {
        
        var msg = String.format("%s is %s years old", name, age);
        return msg;
    }
}

@GetMapping("/customHeader")
ResponseEntity<String> customHeader() {
    HttpHeaders headers = new HttpHeaders();
    headers.add("Custom-Header", "foo");
         
    return new ResponseEntity<>(
      "Custom header set", headers, HttpStatus.OK);
}

import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Component;

@Component
@Qualifier("manager")
public class Manager implements Person {

    @Override
    public String info() {
        return "Manager";
    }
}

@SpringBootApplication
public class SpringBootDemo {
   public static void main(String args[]) {
      SpringApplication.run(SpringBootDemo.class, args);
   }
}

@Configuration
@EnableAutoConfiguration(exclude={DataSourceAutoConfiguration.class})
public class SpringBootDemo {
  //.. Java code
}

@Configuration
@Profile("dev")
public class DevConfigurations {
    // DEV Configurations
}
@Configuration
@Profile("prod")
public class ProdConfigurations {
    // Production Configurations
}

http://localhost:8080/actuator

----
{
  "_links": {
    "self": {
      "href": "http://localhost:8080/actuator",
      "templated": false
    },
    "health": {
      "href": "http://localhost:8080/actuator/health",
      "templated": false
    },
    "info": {
      "href": "http://localhost:8080/actuator/info",
      "templated": false
    }
  }
}

# Disable an endpoint
management.endpoint.[endpoint-name].enabled=false

# Specific example for 'health' endpoint
management.endpoint.health.enabled=false

# Instead of enabled by default, you can change to mode
# where endpoints need to be explicitly enabled
management.endpoints.enabled-by-default=false

@Component
public class CommandLineAppStartupRunner implements CommandLineRunner {
    private static final Logger logger = LoggerFactory.getLogger(CommandLineAppStartupRunner.class);
    @Override
    public void run(String...args) throws Exception {
        logger.info("Application started with command-line arguments: {} . 
        \n To kill this application, press Ctrl + C.", Arrays.toString(args));
    }
}

@Component
public class AppStartupRunner implements ApplicationRunner {
    private static final Logger logger = LoggerFactory.getLogger(AppStartupRunner.class);
    @Override
    public void run(ApplicationArguments args) throws Exception {
        logger.info("Your application started with option names : {}", args.getOptionNames());
    }
}

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@RestController
public class Application {

    @RequestMapping("/")
    public String home() {
        return "Hello Docker World";
    }

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

@RestController
public class WelcomeController {

    @GetMapping("/greeting")
    String greeting() throws Exception {
      //
    }

    @ExceptionHandler({Exception.class})
    public  handleException(){
       //
    }
}

@ControllerAdvice
public class GlobalRestExceptionHandler extends ResponseEntityExceptionHandler {

    @ResponseStatus(HttpStatus.BAD_REQUEST)
    @ExceptionHandler(Exception.class)
    public void defaultExceptionHandler() {
        // Nothing to do
    }
}

@RestControllerAdvice
public class RestExceptionHandler {

@ExceptionHandler(CustomNotFoundException.class)
public ApiErrorResponse handleNotFoundException(CustomNotFoundException ex) {

ApiErrorResponse response = new ApiErrorResponse.ApiErrorResponseBuilder()
      .withStatus(HttpStatus.NOT_FOUND)
      .withError_code("NOT_FOUND")
      .withMessage(ex.getLocalizedMessage()).build();

    return responseMsg;
    }
}

@Cacheable(value="books", key="#isbn")
public Book findStoryBook(ISBN isbn, boolean checkWarehouse, boolean includeUsed)

public class Student {
 
    String id;
    String name;
    String clz;
 
    public Student(String id, String name, String clz) {
        super();
        this.id = id;
        this.name = name;
        this.clz = clz;
    } 
    //Setters and getters
}

import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Service;
import com.example.springcache.domain.Student;
 
@Service
public class StudentService {

    @Cacheable("student")
    public Student getStudentByID(String id) {

        try {
            System.out.println("Going to sleep for 5 Secs.. to simulate backend call.");
            Thread.sleep(1000*5);
        }
        catch (InterruptedException e) {
            e.printStackTrace();
        }
        return new Student(id, "Pradeep", "V");
    }
}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import com.example.springcache.domain.Student;
import com.example.springcache.service.StudentService;
 
@RestController
public class StudentController {
 
    @Autowired
    StudentService studentService;
 
    @GetMapping("/student/{id}")
    public Student findStudentById(@PathVariable String id) {

        System.out.println("Searching by ID  : " + id);
        return studentService.getStudentByID(id);
    }
}

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;
 
@SpringBootApplication
@EnableCaching
public class SpringCacheApplication {
 
    public static void main(String[] args) {
        SpringApplication.run(SpringCacheApplication.class, args);
    }
}

import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.example.springbootswagger2.model.Student;
 
@RestController
public class Swagger2DemoRestController {
 
    List<Student> students = new ArrayList<Student>();
    {
        students.add(new Student("Sajal", "IV", "India"));
        students.add(new Student("Lokesh", "V", "India"));
        students.add(new Student("Kajal", "III", "USA"));
        students.add(new Student("Sukesh", "VI", "USA"));
    }
 
    @RequestMapping(value = "/getStudents")
    public List<Student> getStudents() {
        return students;
    }
 
    @RequestMapping(value = "/getStudent/{name}")
    public Student getStudent(@PathVariable(value = "name") String name) {
        return students.stream().filter(x -> x.getName().equalsIgnoreCase(name)).collect(Collectors.toList()).get(0);
    }
 
    @RequestMapping(value = "/getStudentByCountry/{country}")
    public List<Student> getStudentByCountry(@PathVariable(value = "country") String country) {
        System.out.println("Searching Student in country : " + country);
        List<Student> studentsByCountry = students.stream().filter(x -> x.getCountry().equalsIgnoreCase(country))
                .collect(Collectors.toList());
        System.out.println(studentsByCountry);
        return studentsByCountry;
    }
 
    @RequestMapping(value = "/getStudentByClass/{cls}")
    public List<Student> getStudentByClass(@PathVariable(value = "cls") String cls) {
        return students.stream().filter(x -> x.getCls().equalsIgnoreCase(cls)).collect(Collectors.toList());
    }
}

public class Student {
     
    private String name;
    private String cls;
    private String country;
 
    public Student(String name, String cls, String country) {
        super();
        this.name = name;
        this.cls = cls;
        this.country = country;
    }
 
    public String getName() {
        return name;
    }
 
    public String getCls() {
        return cls;
    }
 
    public String getCountry() {
        return country;
    }
 
    @Override
    public String toString() {
        return "Student [name=" + name + ", cls=" + cls + ", country=" + country + "]";
    }
}

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import com.google.common.base.Predicates;
import springfox.documentation.builders.RequestHandlerSelectors;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;
import springfox.documentation.swagger2.annotations.EnableSwagger2;
 
@Configuration
@EnableSwagger2
public class Swagger2UiConfiguration extends WebMvcConfigurerAdapter
{
    @Bean
    public Docket api() {
        // @formatter:off
        //Register the controllers to swagger
        //Also it is configuring the Swagger Docket
        return new Docket(DocumentationType.SWAGGER_2).select()
                // .apis(RequestHandlerSelectors.any())
                .apis(Predicates.not(RequestHandlerSelectors.basePackage("org.springframework.boot")))
                // .paths(PathSelectors.any())
                // .paths(PathSelectors.ant("/swagger2-demo"))
                .build();
        // @formatter:on
    }
 
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry)
    {
        //enabling swagger-ui part for visual documentation
        registry.addResourceHandler("swagger-ui.html").addResourceLocations("classpath:/META-INF/resources/");
        registry.addResourceHandler("/webjars/**").addResourceLocations("classpath:/META-INF/resources/webjars/");
    }
}

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
 
@Entity
@Table(name="TBL_EMPLOYEES")
public class EmployeeEntity {
 
    @Id
    @GeneratedValue
    private Long id;
     
    @Column(name="first_name")
    private String firstName;
     
    @Column(name="last_name")
    private String lastName;
     
    @Column(name="email", nullable=false, length=200)
    private String email;
     
    //Setters and getters
 
    @Override
    public String toString() {
        return "EmployeeEntity [id=" + id + ", firstName=" + firstName +
                ", lastName=" + lastName + ", email=" + email   + "]";
    }
}

import org.springframework.data.repository.PagingAndSortingRepository;
import org.springframework.stereotype.Repository;
import com.springbatchexample.demo.entity.EmployeeEntity;
 
@Repository
public interface EmployeeRepository
        extends PagingAndSortingRepository<EmployeeEntity, Long> {
 
}

@RestController
@RequestMapping("/employees")
public class EmployeeController
{
    @Autowired
    EmployeeService service;
 
    @GetMapping
    public ResponseEntity<List<EmployeeEntity>> getAllEmployees(
                        @RequestParam(defaultValue = "0") Integer pageNo,
                        @RequestParam(defaultValue = "10") Integer pageSize,
                        @RequestParam(defaultValue = "id") String sortBy)
    {
        List<EmployeeEntity> list = service.getAllEmployees(pageNo, pageSize, sortBy);
 
        return new ResponseEntity<List<EmployeeEntity>>(list, new HttpHeaders(), HttpStatus.OK);
    }
}

@Service
public class EmployeeService
{
    @Autowired
    EmployeeRepository repository;
     
    public List<EmployeeEntity> getAllEmployees(Integer pageNo, Integer pageSize, String sortBy)
    {
        Pageable paging = PageRequest.of(pageNo, pageSize, Sort.by(sortBy));
 
        Page<EmployeeEntity> pagedResult = repository.findAll(paging);
         
        if(pagedResult.hasContent()) {
            return pagedResult.getContent();
        } else {
            return new ArrayList<EmployeeEntity>();
        }
    }
}

Pageable paging = PageRequest.of(pageNo, pageSize);
Page<EmployeeEntity> pagedResult = repository.findAll(paging);

Pageable paging = PageRequest.of(pageNo, pageSize, Sort.by("email"));
Page<EmployeeEntity> pagedResult = repository.findAll(paging);

Sort sortOrder = Sort.by("email");
List<EmployeeEntity> list = repository.findAll(sortOrder);

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableScheduling;

@SpringBootApplication
@EnableScheduling
public class SchedulerDemoApplication {

	public static void main(String[] args) {
		SpringApplication.run(SchedulerDemoApplication.class, args);
	}
}

@Scheduled(fixedRate = 2000)
public void scheduleTaskWithFixedRate() {
    logger.info("Fixed Rate Task :: Execution Time - {}", dateTimeFormatter.format(LocalDateTime.now()) );
}

@Scheduled(cron = "0 * * * * ?")
public void scheduleTaskWithCronExpression() {
    logger.info("Cron Task :: Execution Time - {}", dateTimeFormatter.format(LocalDateTime.now()));
}

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@Configuration
public class MvcConfig extends WebMvcConfigurerAdapter {
   @Override
   public void addViewControllers(ViewControllerRegistry registry) {
      registry.addViewController("/home").setViewName("home");
      registry.addViewController("/").setViewName("home");
      registry.addViewController("/hello").setViewName("hello");
      registry.addViewController("/login").setViewName("login");
   }
}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;

@Configuration
@EnableWebSecurity
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {
   @Override
   protected void configure(HttpSecurity http) throws Exception {
      http
         .authorizeRequests()
            .antMatchers("/", "/home").permitAll()
            .anyRequest().authenticated()
            .and()
         .formLogin()
            .loginPage("/login")
            .permitAll()
            .and()
            .logout()
            .permitAll();
   }
   @Autowired
   public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
      auth
         .inMemoryAuthentication()
         .withUser("user").password("password").roles("USER");
   }
}

@RequestMapping(value = "/products")
@CrossOrigin(origins = "http://localhost:8080")
public ResponseEntity<Object> getProduct() {
   return null;
}

@Bean
public WebMvcConfigurer corsConfigurer() {
   return new WebMvcConfigurerAdapter() {
      @Override
      public void addCorsMappings(CorsRegistry registry) {
         registry.addMapping("/products").allowedOrigins("http://localhost:9000");
      }    
   };
}

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@SpringBootApplication
public class DemoApplication {
   public static void main(String[] args) {
      SpringApplication.run(DemoApplication.class, args);
   }
   @Bean
   public WebMvcConfigurer corsConfigurer() {
      return new WebMvcConfigurerAdapter() {
         @Override
         public void addCorsMappings(CorsRegistry registry) {
            registry.addMapping("/products").allowedOrigins("http://localhost:8080");
         }
      };
   }
}

@Override
protected void configure(HttpSecurity http) throws Exception {
    http
      .csrf().disable();
}

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import java.util.Arrays;
import java.util.List;

@Controller
public class HelloController {

    private static final Logger logger = LoggerFactory.getLogger(HelloController.class);

    @GetMapping("/")
    public String hello(Model model) {

        List<Integer> data = Arrays.asList(1, 2, 3, 4, 5);

        logger.debug("Hello from Logback {}", data);
        model.addAttribute("num", data);

        return "index"; // index.html
    }
}

import org.springframework.batch.core.StepContribution;
import org.springframework.batch.core.scope.context.ChunkContext;
import org.springframework.batch.core.step.tasklet.Tasklet;
import org.springframework.batch.repeat.RepeatStatus;
 
public class TaskOne implements Tasklet {
 
    public RepeatStatus execute(StepContribution contribution, ChunkContext chunkContext) throws Exception
    {
        System.out.println("TaskOne start..");
        // ... some code
        System.out.println("TaskOne done..");
        return RepeatStatus.FINISHED;
    }   
}

import org.springframework.batch.core.StepContribution;
import org.springframework.batch.core.scope.context.ChunkContext;
import org.springframework.batch.core.step.tasklet.Tasklet;
import org.springframework.batch.repeat.RepeatStatus;
 
public class TaskTwo implements Tasklet {
 
    public RepeatStatus execute(StepContribution contribution, ChunkContext chunkContext) throws Exception 
    {
        System.out.println("TaskTwo start..");
        // ... some code
        System.out.println("TaskTwo done..");
        return RepeatStatus.FINISHED;
    }   
}

import org.springframework.batch.core.Job;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.configuration.annotation.EnableBatchProcessing;
import org.springframework.batch.core.configuration.annotation.JobBuilderFactory;
import org.springframework.batch.core.configuration.annotation.StepBuilderFactory;
import org.springframework.batch.core.launch.support.RunIdIncrementer;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
 
import com.springbatchexample.demo.tasks.TaskOne;
import com.springbatchexample.demo.tasks.TaskTwo;
 
@Configuration
@EnableBatchProcessing
public class BatchConfig {
     
    @Autowired
    private JobBuilderFactory jobs;
 
    @Autowired
    private StepBuilderFactory steps;
     
    @Bean
    public Step stepOne(){
        return steps.get("stepOne")
                .tasklet(new TaskOne())
                .build();
    }
     
    @Bean
    public Step stepTwo() {
        return steps.get("stepTwo")
                .tasklet(new TaskTwo())
                .build();
    }  
     
    @Bean
    public Job demoJob() {
        return jobs.get("demoJob")
                .incrementer(new RunIdIncrementer())
                .start(stepOne())
                .next(stepTwo())
                .build();
    }
}

import org.springframework.batch.core.Job;
import org.springframework.batch.core.JobParameters;
import org.springframework.batch.core.JobParametersBuilder;
import org.springframework.batch.core.launch.JobLauncher;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
 
@SpringBootApplication
public class App implements CommandLineRunner {
    @Autowired
    JobLauncher jobLauncher;
     
    @Autowired
    Job job;
     
    public static void main(String[] args) {
        SpringApplication.run(App.class, args);
    }
 
    @Override
    public void run(String... args) throws Exception {
        JobParameters params = new JobParametersBuilder()
                    .addString("JobID", String.valueOf(System.currentTimeMillis()))
                    .toJobParameters();
        jobLauncher.run(job, params);
    }
}

@Component
public class ProductServiceInterceptor implements HandlerInterceptor {
   @Override
   public boolean preHandle(
      HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
      
       log.info("[preHandle][" + request + "]" + "[" + request.getMethod()
      + "]" + request.getRequestURI() + getParameters(request));
      return true;
   }
   @Override
   public void postHandle(
      HttpServletRequest request, HttpServletResponse response, Object handler, 
      ModelAndView modelAndView) throws Exception {
          log.info("[postHandle][" + request + "]");
      }
   
   @Override
   public void afterCompletion(HttpServletRequest request, HttpServletResponse response, 
      Object handler, Exception ex) throws Exception {
           if (ex != null) {
              ex.printStackTrace();
           }
           log.info("[afterCompletion][" + request + "][exception: " + ex + "]");
      }
}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.security.crypto.password.PasswordEncoder;
 
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {
 
    @Autowired
    PasswordEncoder passwordEncoder;
 
    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        auth.inMemoryAuthentication()
        .passwordEncoder(passwordEncoder)
        .withUser("user").password(passwordEncoder.encode("123456")).roles("USER")
        .and()
        .withUser("admin").password(passwordEncoder.encode("123456")).roles("USER", "ADMIN");
    }
 
    @Bean
    public PasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }
 
    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.authorizeRequests()
        .antMatchers("/login")
            .permitAll()
        .antMatchers("/**")
            .hasAnyRole("ADMIN", "USER")
        .and()
            .formLogin()
            .loginPage("/login")
            .defaultSuccessUrl("/home")
            .failureUrl("/login?error=true")
            .permitAll()
        .and()
            .logout()
            .logoutSuccessUrl("/login?logout=true")
            .invalidateHttpSession(true)
            .permitAll()
        .and()
            .csrf()
            .disable();
    }
}

import org.springframework.security.web.context.AbstractSecurityWebApplicationInitializer;
public class SpringSecurityInitializer extends AbstractSecurityWebApplicationInitializer {
    //no code needed
}

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
 
public class AppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
 
   @Override
   protected Class<?>[] getRootConfigClasses() {
      return new Class[] { HibernateConfig.class, SecurityConfig.class };
   }
 
   @Override
   protected Class<?>[] getServletConfigClasses() {
      return new Class[] { WebMvcConfig.class };
   }
 
   @Override
   protected String[] getServletMappings() {
      return new String[] { "/" };
   }
}

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import org.springframework.security.core.Authentication;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.web.authentication.logout.SecurityContextLogoutHandler;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
 
@Controller
public class LoginController
{
    @RequestMapping(value = "/login", method = RequestMethod.GET)
    public String loginPage(@RequestParam(value = "error", required = false) String error,
                            @RequestParam(value = "logout", required = false) String logout,
                            Model model) {
        String errorMessge = null;
        if(error != null) {
            errorMessge = "Username or Password is incorrect !!";
        }
        if(logout != null) {
            errorMessge = "You have been successfully logged out !!";
        }
        model.addAttribute("errorMessge", errorMessge);
        return "login";
    }
  
    @RequestMapping(value="/logout", method = RequestMethod.GET)
    public String logoutPage (HttpServletRequest request, HttpServletResponse response) {
        Authentication auth = SecurityContextHolder.getContext().getAuthentication();
        if (auth != null){   
            new SecurityContextLogoutHandler().logout(request, response, auth);
        }
        return "redirect:/login?logout=true";
    }
}

package com.javaexample.websocket.config;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {

	public static void main(String[] args) {
		SpringApplication.run(Application.class, args);
	}
}

package com.javaexample.websocket.config;
import java.io.IOException;
import org.json.JSONObject;
import org.springframework.stereotype.Component;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.TextWebSocketHandler;

@Component
public class SocketTextHandler extends TextWebSocketHandler {

	@Override
	public void handleTextMessage(WebSocketSession session, TextMessage message)
			throws InterruptedException, IOException {

		String payload = message.getPayload();
		JSONObject jsonObject = new JSONObject(payload);
		session.sendMessage(new TextMessage("Hi " + jsonObject.get("user") + " how may we help you?"));
	}

}

package com.javaexample.websocket.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.config.annotation.EnableWebSocket;
import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;

@Configuration
@EnableWebSocket
public class WebSocketConfig implements WebSocketConfigurer {

	public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
		registry.addHandler(new SocketTextHandler(), "/user");
	}

}