Java NIO之Buffer中flip()、rewind()、clear()方法解析

Java NIO之Buffer中flip()、rewind()、clear()方法解析

1、flip()

    public final Buffer flip() {limit = position;//将当前的position位置赋值给limitposition = 0;//将position赋值为0，即归位mark = -1;return this;}

2、rewind()

    public final Buffer rewind() {position = 0;//只是将position归位，limit不变mark = -1;return this;}

3、clear()

    public final Buffer clear() {position = 0;//将position归位limit = capacity;//将capacity赋值给limit，使limit归位mark = -1;return this;}

4、示意图

5、实例

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;public class TestNIO {public static void main(String[] args) {ByteBuffer buf = ByteBuffer.allocate(1024);buf.put("whataya want from me".getBytes());buf.put(", as long as you love me".getBytes());buf.flip();buf.put("1234567".getBytes());wind();while (buf.hasRemaining())System.out.print((char) ());buf.clear();while (buf.hasRemaining())System.out.print(() ());}
}

运行结果：

1234567 want from me, as long as you love me

1234567 want from me, as long as you love me…后面有许多空格填充

Process finished with exit code 0