1、客户端MyClient.java
1 import java.io.*;
2 import java.net.*;
3
4 public class MyClient
5 {
6 public static void main(String[] args)throws Exception
7 {
8 Socket s = new Socket("192.168.1.1" , 30000);
9 // 客户端启动ClientThread线程不断读取来自服务器的数据
10 new Thread(new ClientThread(s)).start();11 // 获取该Socket对应的输出流
12 PrintStream ps = new PrintStream(s.getOutputStream());
13 String line = null;
14 // 不断读取键盘输入
15 BufferedReader br = new BufferedReader(
16 new InputStreamReader(System.in));
17 while ((line = br.readLine()) != null)
18 {
19 // 将用户的键盘输入内容写入Socket对应的输出流
20 ps.println(line);
21 }
22 }
23 }
2、加入多线程，ClientThread.java
1 import java.io.*;
2 import java.net.*;
3
4 public class ClientThread implements Runnable
5 {
6 // 该线程负责处理的Socket
7 private Socket s;
8 // 该线程所处理的Socket所对应的输入流
9 BufferedReader br = null;
10 public ClientThread(Socket s)
11 throws IOException
12 {
13 this.s = s;
14 br = new BufferedReader(
15 new InputStreamReader(s.getInputStream()));
16 }
17 public void run()
18 {
19 try
20 {
21 String content = null;
22 // 不断读取Socket输入流中的内容，并将这些内容打印输出
23 while ((content = br.readLine()) != null)
24 {
25 System.out.println(content);
26 }
27 }
28 catch (Exception e)
29 {
30 e.printStackTrace();
31 }
32 }
33 }
3、服务器端MyServer.java
1 import java.net.*;
2 import java.io.*;
3 import java.util.*;
4
5 public class MyServer
6 {
7 // 定义保存所有Socket的ArrayList
8 public static ArrayList<Socket> socketList
9 = new ArrayList<Socket>();
10 public static void main(String[] args)
11 throws IOException
12 {
13 System.out.println("222222……");
14 ServerSocket ss = new ServerSocket
15
16 (30000);
17 while(true)
18 {
19 System.out.println("服务器等待链接……");
20 // 此行代码会阻塞，将一直等待别人的连接
21 Socket s = ss.accept();
22 socketList.add(s);
23 // 每当客户端连接后启动一条ServerThread线程为该客户端服务
24 new Thread(new ServerThread
25
26 (s)).start();
27 }
28 }
29 }
4、为服务器端通信加入多线程
1 import java.io.*;
2 import java.net.*;
3 import java.util.*;
4
5 // 负责处理每个线程通信的线程类
6 public class ServerThread implements Runnable {
7 // 定义当前线程所处理的Socket
8 Socket s = null;
9 // 该线程所处理的Socket所对应的输入流
10 BufferedReader br = null;
11
12 public ServerThread(Socket s) throws IOException {
13 System.out.println("4444444……");
14 this.s = s;
15 // 初始化该Socket对应的输入流
16 String ip=s.getInetAddress().getHostAddress();
17 System.out.println("ip地址为"+ip+"........connected!!!");
18 br = new BufferedReader(new InputStreamReader(s.getInputStream(),
19 "utf-8")); //
20 }
21
22 public void run() {
23 System.out.println("555555……");
24 try {
25 System.out.println("4444444……");
26 String content = null;
27 // 采用循环不断从Socket中读取客户端发送过来的数据
28 while ((content = readFromClient()) != null) {
29 /*System.out.println("---"
30 + Arrays.toString(content.getBytes("utf-8")));*/
31 System.out.println("---" +"客户端发来的数据为"+content);
32 System.out.println("===============");
33 // 遍历socketList中的每个Socket，
34 // 将读到的内容向每个Socket发送一次
35 for (Iterator<Socket> it = MyServer.socketList.iterator(); it
36 .hasNext();) {
37 Socket s = it.next();
38 try {
39 System.out.println("666666");
40 OutputStream os = s.getOutputStream();
41 os.write((content+"服务器反馈给客户端ok" + "\n").getBytes("utf-8"));
42 System.out.println("777777");
43 } catch (SocketException e) {
44 e.printStackTrace();
45 // 删除该Socket。
46 it.remove();
47 System.out.println(MyServer.socketList);
48 }
49 }
50 }
51 } catch (IOException e) {
52 e.printStackTrace();
53 }
54 }
55
56 // 定义读取客户端数据的方法
57 private String readFromClient() {
58 try {
59 return br.readLine();
60 }
61 // 如果捕捉到异常，表明该Socket对应的客户端已经关闭
62 catch (IOException e) {
63 e.printStackTrace();
64 System.out.println("客户端已经关闭！！！");
65 // 删除该Socket。
66 MyServer.socketList.remove(s);
67 }
68 return null;
69 }
70 }
来源：https://www.cnblogs.com/Javacxf/p/7173058.html