java网络编程——基于UDP和TCP协议的小例子

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

public class ReceiveDemo {

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

// 创建socket
DatagramSocket socket = new DatagramSocket(9999);

// 创建接受包
byte[] buf = new byte[1024];
DatagramPacket packet = new DatagramPacket(buf, buf.length);

// 接受数据
socket.receive(packet);// 阻塞式

// 解析数据
String ip = packet.getAddress().getHostAddress();
String content = new String(packet.getData(), 0,
packet.getLength());

System.out.println("From:" + ip + "\n" + "content: " + content);

// 释放资源
socket.close();
}

}

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

public class SendDemo {

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

// 创建socket对象
DatagramSocket socket = new DatagramSocket();

// 创建发送包(ip+port在包上，因为是把包发送出去，让包去寻找目的主机上的目标端口)
byte[] buf = "hello udp !".getBytes();
DatagramPacket packet = new DatagramPacket(buf, buf.length, InetAddress
.getByName("192.168.1.100"), 9999);

// 发送
socket.send(packet);
// 释放资源
socket.close();
}

}

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class ServerDemo {

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

// 创建服务器socket对象
ServerSocket ss = new ServerSocket(8888);

// 监听客户端的连接
Socket socket = ss.accept();// 阻塞

// 获取输入流
InputStream is = socket.getInputStream();
byte[] buf = new byte[1024];

// This method blocks until input data is available, end of file is
// detected, or an exception is thrown.
int len = is.read(buf);
String content=new String(buf, 0, len);
System.out.println("收到内容："+content);

//获取输出流，并向客户端反馈（可选）
OutputStream os=socket.getOutputStream();
os.write("Server Received!".getBytes());

//释放资源
socket.close();

//注意：服务器一般是不关的
//ss.close();
}

}

import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;

public class ClientDemo {

public static void main(String[] args) throws Exception {

// 创建客户端socket对象
Socket s = new Socket("192.168.1.100", 8888);

// 获取输出流，并写入数据
OutputStream os = s.getOutputStream();
os.write("hello ,tcp".getBytes());

// 获取输入流，从中取出服务端的反馈信息
InputStream is = s.getInputStream();
byte[] buf = new byte[1024];
int len = is.read(buf);
String content = new String(buf, 0, len);
System.out.println("反馈内容：" + content);

}

}