Project
A Java Direct IO framework which is very simple to use.
Add to your project
<dependency>
<groupId>moe.cnkirito.kdio</groupId>
<artifactId>kdio-core</artifactId>
<version>1.0.0</version>
</dependency>Sample
Notice
// file path should be specific since the different file path determine whether your system support direct io
public static DirectIOLib directIOLib = DirectIOLib.getLibForPath("/");
// you should always write into your disk the Integer-Multiple of block size through direct io.
// in most system, the block size is 4kb
private static final int BLOCK_SIZE = 4 * 1024;
Usually, only specific linux system support direct io. You should own a linux server.
Write
private static void write() throws IOException {
if (DirectIOLib.binit) {
ByteBuffer byteBuffer = DirectIOUtils.allocateForDirectIO(directIOLib, 4 * BLOCK_SIZE);
for (int i = 0; i < BLOCK_SIZE; i++) {
byteBuffer.putInt(i);
}
byteBuffer.flip();
DirectRandomAccessFile directRandomAccessFile = new DirectRandomAccessFile(new File("./database.data"), "rw");
directRandomAccessFile.write(byteBuffer, 0);
} else {
throw new RuntimeException("your system do not support direct io");
}
}Read
public static void read() throws IOException {
if (DirectIOLib.binit) {
ByteBuffer byteBuffer = DirectIOUtils.allocateForDirectIO(directIOLib, 4 * BLOCK_SIZE);
DirectRandomAccessFile directRandomAccessFile = new DirectRandomAccessFile(new File("./database.data"), "rw");
directRandomAccessFile.read(byteBuffer, 0);
byteBuffer.flip();
for (int i = 0; i < BLOCK_SIZE; i++) {
System.out.print(byteBuffer.getInt() + " ");
}
} else {
throw new RuntimeException("your system do not support direct io");
}
}Install & Run
mvn clean install -DskipTests
you will get the sample of direct io test: DirectIOTest.jar
deploy it to a linux server and use
java -jar DirectIOTest.jaryou can try it.
License
kdio is under the Apache 2.0 license.