Java Socket编程系列（一）开发一次性会话的Server和Client

关于什么是Socket：

A socket is one end-point of a two-way communication link between two programs running on the network.

Socket是网络上运行的2个程序之间通信链接的终点。说白了就是代表一条通信链路的两端。

Socket classes are used to represent the connection between a client program and a server program.

Socket类用来代表客户端程序和服务器端程序的连接。

The java.net package provides two classes--Socket and ServerSocket--that implement the client side of the connection and the server side of the connection, respectively

Java中的java.net包提供了Socket和ServerSocket类分别实现连接的客户端和服务端。

Java中如何编写？

服务器端：

package com.dylan.socket;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;

/**
 * 服务器
 *
 * @author xusucheng
 * @create 2017-12-21
 **/
public class Server {
    public static final int PORT = 8858;//监听的端口号

    public static void main(String[] args) throws Exception {
        System.out.println("Server started! Listening...");
        ServerSocket serverSocket = new ServerSocket(PORT);
        Socket server = serverSocket.accept();

        BufferedReader in = new BufferedReader(new InputStreamReader(server.getInputStream()));
        PrintWriter out = new PrintWriter(server.getOutputStream());

        String readLine = in.readLine();
        if (readLine != null) {
            System.out.println("Receive message from Client: " + readLine);
            out.println("Roger!");
        }

        out.close();
        in.close();
        server.close();
        serverSocket.close();

    }

}

客户端：

package com.dylan.socket;

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

/**
 * 客户端
 *
 * @author xusucheng
 * @create 2017-12-20
 **/
public class Client {
    public static final String HOST = "127.0.0.1";//服务器地址
    public static final int PORT = 8858;//服务器端口号

    public static void main(String[] args) throws Exception{
        Socket client = new Socket(HOST,PORT);
        //创建输入流
        BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream()));
        //创建输出流
        PrintWriter out = new PrintWriter(client.getOutputStream(),true);
        //向服务器程序发送信息
        out.println("Hello Server! This is Client! ");
        //接收来自服务器程序的响应
        String readLine=in.readLine();
        if(readLine!=null){
            System.out.println("Receive message from Server: "+readLine);
        }

        //关闭链接
        out.close();
        in.close();
        client.close();
    }
}

启动

服务器端

Server started! Listening...

Receive message from Client: Hello Server! This is Client!

客户端：

Receive message from Server: Roger!