Client.java:

package TCP.multiThread;

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

/**
 *客户端程序
 *在客户端中，发送数据和接收数据应该是同步的，不应该存在先后顺序，所以要用线程来实现同步。
 */
public class Client {
    public static void main(String[] args) throws IOException {
        Socket client = new Socket("127.0.0.1",8888);
        //输出数据
        new Thread(new Send(client)).start();//一条发送线程
        new Thread(new Receive(client)).start();
    }
}

CloseUtil.java:

package TCP.multiThread;
import java.io.Closeable;
import java.io.IOException;

/**
 * 关闭流的方法
 */
public class CloseUtil {
    public  static void closeAll(Closeable... io){
        for(Closeable temp:io){
            if(null != temp){
                try {
                    temp.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

Receive.java:

package TCP.multiThread;

import java.io.DataInputStream;
import java.io.IOException;
import java.net.Socket;

/**
 * 接收线程
 */
public class Receive implements Runnable{
    private DataInputStream dis;
    private boolean isRunning = true;
    public Receive(){

    }
    public Receive(Socket client){
        this();
        try {
            dis = new DataInputStream(client.getInputStream());
        } catch (IOException e) {
            e.printStackTrace();
            isRunning = false;
            CloseUtil.closeAll(dis);
        }
    }
    public String receive(){
        String msg = "";
        try {
            msg = dis.readUTF();
        } catch (IOException e) {
            e.printStackTrace();
            isRunning = false;
            CloseUtil.closeAll(dis);
        }
        return msg;
    }
    @Override
    public void run() {
        while (isRunning){
            System.out.println(receive());
        }

    }
}

Send.java:

package TCP.multiThread;

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.Socket;

/**
 * 发送线程
 */
public class Send implements Runnable{
    private BufferedReader console;
    private DataOutputStream dos;
    private boolean isRunning=true;
    Send(){
        console = new BufferedReader(new InputStreamReader(System.in));
    }
    Send(Socket client){
        this();
        try{
            dos = new DataOutputStream(client.getOutputStream());
        } catch (IOException e) {
            e.printStackTrace();
            isRunning = false;
            CloseUtil.closeAll(dos,console);
        }
    }

    /**
     * 从控制台接收数据
     * 发送数据
     */
    private String getMsgFromConsole(){
        try {
            return console.readLine();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return "";
    }
    public void send(){
        String msg = getMsgFromConsole();
        if(null != msg && !msg.equals("")){
            try {
                dos.writeUTF(msg);
                dos.flush();
            } catch (IOException e) {
                e.printStackTrace();
                isRunning = false;
                CloseUtil.closeAll(dos,console);
            }

        }
    }

    @Override
    public void run() {
        while (isRunning){
            send();
        }
    }

}

Server.java:

package TCP.multiThread;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;

/*
 *创建服务器
 */
public class Server {

    List<MyChannel> all = new ArrayList<MyChannel>();
    public static void main(String[] args) throws IOException {
        new Server().start();
    }
    public void start() throws IOException {
        ServerSocket server = new ServerSocket(8888);
        Socket client;
        while (true){
            //一个客户端对应一个线程，同时需要把其他用户发送的信息搬运给其他的用户，所以需要维护一个线程数组，接收到一个用户发送的信息之后，把该信息发送给数组内其他用户:"other.send(msg);"
            client = server.accept();
            MyChannel channel = new MyChannel(client);
            all.add(channel);
            new Thread(channel).start();
        }
    }
    private class MyChannel implements Runnable{
        /**
         * 一个客户端一条道路
         */

        private DataInputStream dis;
        private DataOutputStream dos;
        private boolean isRunning = true;
        MyChannel(Socket client){
            try {
                dis = new DataInputStream(client.getInputStream());
                dos = new DataOutputStream(client.getOutputStream());
            } catch (IOException e) {
                e.printStackTrace();
                isRunning = false;
                CloseUtil.closeAll(dis,dos);
            }
        }
        private String receive(){
            String msg = "";
            try {
                msg = dis.readUTF();
            } catch (IOException e) {
                e.printStackTrace();
                isRunning = false;
                CloseUtil.closeAll(dis,dos);
                all.remove(this);
            }
            return msg;
        }
        private String send(String msg){
            if(null != msg && !msg.equals("")){
                try {
                    dos.writeUTF(msg);
                    dos.flush();
                } catch (IOException e) {
                    e.printStackTrace();
                    isRunning = false;
                    CloseUtil.closeAll(dos,dis);
                    all.remove(this);
                }
            }
            return "";
        }

        private void sendOthers(){
            String msg = receive();
            for(MyChannel other:all){
                if(other == this){
                    continue;
                }
                other.send(msg);
            }
        }
        @Override
        public void run() {
            while (isRunning){
                sendOthers();
            }

        }
    }
}