Java学习-UDP编程

【简介】

UDP:以数据为中心 非面向连接 不安全 数据可能丢失 效率高

类 DatagramSocket和DatagramPacket

1.客户端

1）创建客户端 DatagramSocket类 + 指定发送端口

2）准备数据 字节数组

3）打包DatagramPacket + 服务器地址 及 端口

4）发送

5）释放资源

2.服务器端

1）创建服务器 DatagramSocket类 + 指定接收端口

2）准备接收容器 字节数组 封装DatagramPacket

3）封装成包

4）接收数据

5）分析

6）释放资源

【传入字符串】

客户端

package com.anqi.UDP;

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

public class MyClient {
public static void main(String[] args) throws IOException {
//1.创建客户端 + 端口
DatagramSocket client = new DatagramSocket(6666);
//2.准备数据
String msg = "编程";
byte[] data = msg.getBytes();
//3.打包 发送的地点以及端口
DatagramPacket packet = new DatagramPacket(data,data.length,new InetSocketAddress("localhost",8888));
//4.发送
client.send(packet);
//5.释放
client.close();
}
}

服务器端

package com.anqi.UDP;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
public class MyServer {
public static void main(String[] args) throws IOException {
//1.创建服务器端 + 端口
DatagramSocket server = new DatagramSocket(8888);
//2.准备接收容器
byte[] container = new byte[1024];
//3.封装成包
//DatagramPacket(byte[] buf, int length)
DatagramPacket packet = new DatagramPacket(container,container.length);
//4.接收数据
server.receive(packet);
//5.分析数据
byte[] data = packet.getData();
int len = packet.getLength();
System.out.println(new String(data,0,len));
//5.释放
server.close();
}
}

【传入double】

客户端

package com.anqi.UDP;

import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;

public class Client {
public static void main(String[] args) throws IOException {
//1.创建客户端 + 端口
DatagramSocket client = new DatagramSocket(6666);
//2.准备数据
double num = 89.12;
byte[] data = convert(num);
//3.打包 发送的地点以及端口
DatagramPacket packet = new DatagramPacket(data,data.length,new InetSocketAddress("localhost",9888));
//4.发送
client.send(packet);
//5.释放
client.close();
}
public static byte[] convert(double num) throws IOException{
byte[] data = null;
ByteArrayOutputStream bos = new ByteArrayOutputStream();
DataOutputStream dos = new DataOutputStream(bos);
dos.writeDouble(num);
dos.flush();
//获取数据
data = bos.toByteArray();
dos.close();
return data;
}
}

服务器端

package com.anqi.UDP;

import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
public class Server {
public static void main(String[] args) throws IOException {
//1.创建服务器端 + 端口
DatagramSocket server = new DatagramSocket(9888);
//2.准备接收容器
byte[] container = new byte[1024];
//3.封装成包
//DatagramPacket(byte[] buf, int length)
DatagramPacket packet = new DatagramPac
4000
ket(container,container.length);
//4.接收数据
server.receive(packet);
//5.分析数据
double data  = convert(packet.getData());
System.out.println(data);
//5.释放
server.close();
}
public static double convert(byte[] data) throws IOException{
DataInputStream dis = new DataInputStream(new ByteArrayInputStream(data));
double num = dis.readDouble();
dis.close();
return num;
}
}