java filebytebuff

Posted 2022-03-28 程序员超时空

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.RandomAccessFile;

import java.nio.ByteBuffer;

import java.nio.channels.FileChannel;

public class javatest

long getInt(byte[] datas)

// TODO Auto-generated method stub

ByteBuffer temp = ByteBuffer.allocate(datas.length);

temp.put(datas);

temp.flip();

return temp.getLong();

public static void main(String[] args) throws IOException

// byte [] bbuf = new byte[] 0x00,0x00,0x00,0x01;

// javatest jt= new javatest();

// long a = jt.getInt(bbuf);

//

// System.out.println(“a”+ a);

FileChannel fc = new FileOutputStream(“a.txt”).getChannel();

fc.write(ByteBuffer.wrap(“this is test”.getBytes()));

fc.close();

fc = new RandomAccessFile(“a.txt”, “rw”).getChannel();

fc.position(fc.size());//到最后位置然后 后面的byte加到后面

fc.write(ByteBuffer.wrap(“Some more”.getBytes()));

fc.close();

fc = new FileInputStream(“a.txt”).getChannel();

ByteBuffer buff = ByteBuffer.allocate(100);

fc.read(buff);

buff.flip();

while (buff.hasRemaining()) // 是否到达限定的位置

System.out.println((char) buff.get());