使用Channel进行本地文件读写的简单实例2

使用一个缓冲区进行读写操作：

 public static void main(String[] args) throws IOException {
        FileInputStream fileInputStream = new FileInputStream("1.txt");
        FileChannel channel01 = fileInputStream.getChannel();

        FileOutputStream fileOutputStream=new FileOutputStream("2.txt");
        FileChannel channel02 = fileOutputStream.getChannel();

        ByteBuffer byteBuffer = ByteBuffer.allocate(1024);

        //循环读取
        while(true){
            //清理缓冲区 非常重要
            byteBuffer.clear();
        int read=   channel01.read(byteBuffer);
        if(read==-1){
            break;
        }
        byteBuffer.flip();
        channel02.write(byteBuffer);
        }
fileInputStream.close();
        fileOutputStream.close();
    }
直接通过channel进行读写

public static void main(String[] args) throws IOException {
    FileInputStream fileInputStream = new FileInputStream("d:\\eva.jpg");
    FileOutputStream fileOutputStream = new FileOutputStream("d:\\eva2.jpg");
    FileChannel channel01 = fileInputStream.getChannel();
    FileChannel channel02 = fileOutputStream.getChannel();
    channel02.transferFrom(channel01,0,channel01.size());
 channel01.close();
 channel02.close();
 fileInputStream.close();
 fileOutputStream.close();

}
通过buffer数组进行读写

public static void main(String[] args) throws IOException {
         //使用ServerSocket和socketChannel
    ServerSocketChannel serverSocketChannel=ServerSocketChannel.open();
    InetSocketAddress inetAddress=new InetSocketAddress(7000);
    //绑定端口到socket并启动
    serverSocketChannel.socket().bind(inetAddress);
    //创建buffer[]数组
    ByteBuffer[] byteBuffers = new ByteBuffer[2];
    byteBuffers[0]=ByteBuffer.allocate(5);
    byteBuffers[1]=ByteBuffer.allocate(3);
    //等待客户端连接
    SocketChannel socketChannel=serverSocketChannel.accept();
    int messageLength=8; //假定从客户端接收8个字节
    //循环读取
    while (true){
        int byteRead=0;
      while(byteRead<messageLength){
          long read=socketChannel.read(byteBuffers);
          byteRead+=read;
          System.out.println(byteRead);
      }
       //将所有的buffer进行flip
        Arrays.asList(byteBuffers).forEach(byteBuffer -> byteBuffer.flip());
      //数据读出显示到客户端
        long writeByte=0;
        while(writeByte<messageLength){
            long write=socketChannel.write(byteBuffers);
            writeByte+=write;
        }
        //复位操作
        Arrays.asList(byteBuffers).forEach(byteBuffer -> byteBuffer.clear());
    }
}