Socket 编程

Socket概述

UDP

UDP数据传输流程：

以下是代码实现：

因为UDP是无连接的不可靠传输，所以接收方需要在发送方发送数据之前就启动，否则会接收不到数据。也就是说必须先运行UDPSocketReceive再运行UDPSocketSend。控制台打印如下：
发送方：

Sender Start...

接受方：

Receiver Start...
address:/127.0.0.1---port:61177---content:God bless you!

聊天实现：

package Socket;

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

public class SocketFemale {
    public static void main(String[] args) {
        try {
            new Thread(new Runnable() {
                @Override
                public void run(){
                    try {
                        receive();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }).start();
            send();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //接收消息方法
    private static void receive() throws IOException {
        System.out.println("SocketFemale Receiver Start...");

        //1.创建udp的socket服务,并声明端口号
        DatagramSocket dsReceive = new DatagramSocket(6666);
        //无限循环，一直处于接收状态
        while (true) {
            //2.创建接收数据的数据包
            byte bytes[] = new byte[1024];
            DatagramPacket dp = new DatagramPacket(bytes, bytes.length);

            //3.将数据接收到数据包中
            dsReceive.receive(dp);

            //4.解析数据
            String content = new String(dp.getData(), 0, dp.getLength());
            System.out.println("SocketFemale Receive:" + content);
        }
    }

    private static void send() throws IOException {
        //1.创建socket服务
        DatagramSocket dsSend = new DatagramSocket();

        //将键盘输入的信息转换成输入流再放入到缓冲区
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String line = null;
        while ((line=br.readLine())!=null){
            //2.封装数据
            byte[] bytes = line.getBytes();
            //地址
            InetAddress address =InetAddress.getByName("127.0.0.1");
            //参数：数据、长度、地址、端口
            DatagramPacket dp = new DatagramPacket(bytes,bytes.length,address,7777);

            //3.发送数据包
            dsSend.send(dp);
        }
        //4.关闭socket服务
        dsSend.close();
    }
}

package Socket;

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

public class SocketMale {
    public static void main(String[] args){
        try {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        receive();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }).start();
            send();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //接收消息方法
    private static void receive() throws IOException {
        System.out.println("SocketMale Receiver Start...");

        //1.创建udp的socket服务,并声明端口号
        DatagramSocket dsReceive = new DatagramSocket(7777);
        //无限循环，一直处于接收状态
        while (true) {
            //2.创建接收数据的数据包
            byte[] bytes = new byte[1024];
            DatagramPacket dp = new DatagramPacket(bytes, bytes.length);

            //3.将数据接收到数据包中
            dsReceive.receive(dp);

            //4.解析数据
            String content = new String(dp.getData(), 0, dp.getLength());
            System.out.println("SocketMale Receive:" + content);
        }
        //关闭服务
        // ds.close;
    }

    private static void send() throws IOException {
        //1.创建socket服务
        DatagramSocket dsSend = new DatagramSocket();

        //将键盘输入的信息转换成输入流再放入到缓冲区
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String line = null;
        while ((line=br.readLine())!=null){
            //2.封装数据
            byte[] bytes = line.getBytes();
            //地址
            InetAddress address =InetAddress.getByName("127.0.0.1");
            //参数：数据、长度、地址、端口
            DatagramPacket dp = new DatagramPacket(bytes,bytes.length,address,6666);

            //3.发送数据包
            dsSend.send(dp);
        }
        //4.关闭socket服务
        dsSend.close();
    }
}

TCP

TCP聊天实现：
一个服务端可以同时和多个客户端进行通信。如何区分不同客户端？服务端首先通过accept获取到客户端Socket，然后通过客户端的Socket获取的流进行通讯，服务端得以区分每个客户端。