UDP案例代码

• UDP网络编程的案例代码
• • 普通接收方/发送方代码
  • 多线程方式代码

用于描述发送发与接收方之间的通信

• 接收方

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.Socket;


public class ReveiverTest {

    public static void main(String[] args) {
        DatagramSocket ds = null;
        try {
            // 1.创建DatagramSocket类型的对象并提供端口号
            ds = new DatagramSocket(8888);

            byte[] bArr = new byte[50];
            // 2.创建DatagramPacket类型的对象并提供缓冲区
            DatagramPacket dp = new DatagramPacket(bArr, bArr.length);

            // 3.通过Socket接收数据内容存放到Packet中，调用receive方法
            ds.receive(dp);
            System.out.println("接收到的数据内容为" + new String(bArr, 0, dp.getLength()));

            String ss = "我收到了";
            byte[] bytes = ss.getBytes();
            DatagramPacket dp2 = new DatagramPacket(bytes, bytes.length, dp.getAddress(), dp.getPort());
            ds.send(dp2);
            System.out.println("回复消息成功");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            // 4.关闭Socket
            if (null != ds) {
                ds.close();
            }

        }
    }
}

• 发送方

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;


public class SendTest {

    public static void main(String[] args) {
        DatagramSocket ds = null;
        try {
            // 1. 创建DatagramSocket类型的对象
            ds = new DatagramSocket();

            String s = "你好世界";
            byte[] bytes = s.getBytes();
            // 2.创建DatagramPacket类型的对象并提供接收方的通信地址
            DatagramPacket dp = new DatagramPacket(bytes, bytes.length, InetAddress.getLocalHost(), 8888);
            // 3.通过Socket将Packet中的数据内容发送出去，调用send方法
            ds.send(dp);

            byte[] bArr2 = new byte[50];
            System.out.println("发送数据成功");

            DatagramPacket dp2 = new DatagramPacket(bArr2, bArr2.length);
            ds.receive(dp2);
            System.out.println("回复消息接收成功，内容为：" + new String(bArr2, 0, dp2.getLength()));


        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            // 4.关闭Socket
            ds.close();
        }
    }
}

• 多线程

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;

public class ThreadsTest implements Runnable{
    @Override
    public void run() {
        DatagramSocket ds = null;
        try {
            ds = new DatagramSocket(8888);
            byte[] bArr = new byte[50];
            DatagramPacket dp = new DatagramPacket(bArr, bArr.length);
            while (true) {
                // 3.通过Socket接收数据内容存放到Packet中，调用receive方法
                ds.receive(dp);
                System.out.println("接收到的数据内容为" + new String(bArr, 0, dp.getLength()));
                String ss = "我收到了";
                byte[] bytes = ss.getBytes();
                DatagramPacket dp2 = new DatagramPacket(bytes, bytes.length, dp.getAddress(), dp.getPort());
                ds.send(dp2);
                System.out.println("回复消息成功");
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (null != ds) {
                ds.close();
            }
        }
    }
}

• 接收方

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;


public class ReveiverTest2 {

    public static void main(String[] args) {
        ThreadsTest threadsTest = new ThreadsTest();
        Thread thread = new Thread(threadsTest);
        thread.start();
    }
}

• 发送方（发送方代码复制多份即可表示多个发送方）

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;


public class SendTest1 {

    public static void main(String[] args) {
        DatagramSocket ds = null;
        try {
            // 1. 创建DatagramSocket类型的对象
            ds = new DatagramSocket();

            String s = "你好世界";
            byte[] bytes = s.getBytes();
            // 2.创建DatagramPacket类型的对象并提供接收方的通信地址
            DatagramPacket dp = new DatagramPacket(bytes, bytes.length, InetAddress.getLocalHost(), 8888);
            // 3.通过Socket将Packet中的数据内容发送出去，调用send方法
            ds.send(dp);

            byte[] bArr2 = new byte[50];
            System.out.println("发送数据成功");

            DatagramPacket dp2 = new DatagramPacket(bArr2, bArr2.length);
            ds.receive(dp2);
            System.out.println("回复消息接收成功，内容为：" + new String(bArr2, 0, dp2.getLength()));


        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            // 4.关闭Socket
            ds.close();
        }
    }
}