概要：看过我之前文章的人都知道，client和server之间的通信必不可少的就是socket。而java已经帮我们做了很多事情。

创建Server端

第一步，创建ServerSocket

这个从名字上就可以看出来，服务器上的socket   0.0

ServerSocket serverSocket = new ServerSocket(8888);

第二步，就是接受客户端传来的socket

 Socket socket = serverSocket.accept();

第三步，便是创建输入流和输出流

 BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
 PrintWriter out = new PrintWriter(socket.getOutputStream(), true);

第四步，便是循环读取或者输出，dosomething

        String message;
        while ((message = in.readLine()) != null) {
            System.out.println("收到客户端消息：" + message);
            out.println("服务器已收到消息：" + message);
        }

最后一定不要忘记了关闭这些

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

创建Client端

第一步，创建Socket

Socket socket = new Socket("localhost", 8888);

第二步，便是建立输入流和输出流

    BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
    PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
    BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in));

第三步，便是循环dosomething

        String message;
        while (true) {
            System.out.print("请输入要发送的消息：");
            message = keyboard.readLine();
            out.println(message);

            String response = in.readLine();
            System.out.println("收到服务器回复：" + response);
        }

第四步，老样子，该关闭的关闭。

由于我这里写了while（true）已经写死了，就不用关闭了，因为也抵达不到那里去。

完整代码

package org.cyl.database.net;

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

public class Client {
    public static void main(String[] args) throws IOException {
        Socket socket = new Socket("localhost", 8888);
        System.out.println("已连接到服务器");

        BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
        BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in));

        String message;
        while (true) {
            System.out.print("请输入要发送的消息：");
            message = keyboard.readLine();
            out.println(message);

            String response = in.readLine();
            System.out.println("收到服务器回复：" + response);
        }
    }
}

package org.cyl.database.net;
import java.io.*;
import java.net.*;

public class Server {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(8888);
        System.out.println("服务器已启动，等待客户端连接...");

        Socket socket = serverSocket.accept();
        System.out.println("客户端已连接，IP地址为：" + socket.getInetAddress().getHostAddress());

        BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        PrintWriter out = new PrintWriter(socket.getOutputStream(), true);

        String message;
        while ((message = in.readLine()) != null) {
            System.out.println("收到客户端消息：" + message);
            out.println("服务器已收到消息：" + message);
        }

        in.close();
        out.close();
        socket.close();
        serverSocket.close();
    }
}

结果图：