JavaSocket UDP Byte类型的收发

最新推荐文章于 2024-11-14 09:25:12 发布

转载最新推荐文章于 2024-11-14 09:25:12 发布 · 129 阅读

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原文链接：http://www.cnblogs.com/super119/archive/2011/01/03/1924563.html

文章标签：

#java #网络

本文介绍了一个使用Java实现的UDP通信示例程序，演示了如何发送和接收UDP数据包，并提供了将两个byte数组相加的方法。该示例展示了如何定义数据包、发送请求及接收响应的过程。

package com.zchome;

import java.net.*;
import java.io.*;

public class testudp {
    public static void main(String[] args) {
        DatagramSocket s = null;
        try {
            s = new DatagramSocket();
            byte[] control_buffer = new byte[4];
            byte[] content_buffer = null;
            byte[] result_buffer = null;
            byte[] receive_buffer = new byte[100];
            for (int nloopindex = 0; nloopindex < 10; nloopindex++) {
                //define first 4 Bytes
                control_buffer[0] = 0x00;
                control_buffer[1] = 0x01;
                control_buffer[2] = 0x01;
                control_buffer[3] = 0x00;

                String IPAddress = "192.168.0.2";
                content_buffer = IPAddress.getBytes();

                result_buffer = Toolkit.getInstance().addByteBuffers(control_buffer, content_buffer);

                InetAddress ia = InetAddress.getByName("192.168.0.9");

                DatagramPacket dgp = new DatagramPacket(result_buffer, result_buffer.length, ia, 10002);
                s.send(dgp);

                dgp = new DatagramPacket(receive_buffer, receive_buffer.length, ia, 10002);
                s.receive(dgp);
                System.out.println(new String(dgp.getData()));
            }
        }
        catch (IOException e) {
            System.out.println(e.toString());
        }
        finally {
            if (s != null)
                s.close();
        }
    }
}

这里还有一个将两个byte数组相加的方法：

/*
* Toolkit.java
*
* Created on 2004年8月18日, 上午10:53
*/

package com.zchome;

/**
*
* @author  张超
*/
public class Toolkit {

    /** Creates a new instance of Toolkit */
    private Toolkit() {
    }

    private static Toolkit _instance = null;

    public static Toolkit getInstance() {
        if (_instance == null)
            _instance = new Toolkit();
        return _instance;
    }

    public byte[] addByteBuffers(byte[] first, byte[] second)
    {
        int nloopindex = 0;
        int first_length = first.length;
        int second_length = second.length;
        byte[] return_bytes = new byte[first_length + second_length];

        for (nloopindex = 0; nloopindex < first_length; nloopindex++)
        {
            return_bytes[nloopindex] = first[nloopindex];
        }
        for (nloopindex = 0; nloopindex < second_length; nloopindex++)
        {
            return_bytes[first_length + nloopindex] = second[nloopindex];
        }

        return return_bytes;
    }

}

一点注意：在s.receive一句之前加上这句：

socket.setSoTimeout(5000); //设置5秒的timeout

这样可以防止，在没有东西receive的时候，程序被block

转载于:https://www.cnblogs.com/super119/archive/2011/01/03/1924563.html