java socket通信：聊天器

Posted 2020-11-30 然年酉鱼

目的：实现多个客户之间的通信

首先，这个聊天器的框架是这样的：

 

 对于服务器端：建立socket，连接到服务器，并且开始监听。

import java.io.*;
import java.util.ArrayList;
import java.util.List;
import java.net.*;
public class MultiTalkServer{
    static int clientnum = 0;
    //创建一个arraylist数组来保存socket,
    public static List <Socket> socketList = new ArrayList <Socket>();
    public static void main(String args[])throws IOException{
        ServerSocket serverSocket = null;
        boolean listening = true;
        try {
            serverSocket= new ServerSocket(4700);
            System.out.println("欢迎来到聊天室。");
        }catch(IOException e) {
            System.out.println("Could not listen on port:4700.");
            System.exit(-1);
        }
        while (listening) {
            clientnum++;
            Socket st = serverSocket.accept();//先创建一个socket
            //此处会阻塞，等待接收
            socketList.add(st);//将这个线程添加到list里
            System.out.println("上线通知： 用户" + clientnum+"上线啦！"); 
            new ServerThread(st,clientnum).start();//再创建一个服务端线程
        }
        serverSocket.close();
    }
}

服务器线程：

import java.io.*;
import java.net.*;
public class ServerThread extends Thread{
    Socket socket = null;//服务器的套接字
    int clientnum;
    String line;
    //将line定义在外面
    public ServerThread(Socket socket,int num){
        this.socket=socket;
        clientnum=num+1;
    }
    public void run() {
        try {
            BufferedReader is = new BufferedReader(new
            InputStreamReader(socket.getInputStream()));//is：从缓存区读入
            
            PrintWriter os = new PrintWriter(socket.getOutputStream());//os：从缓存区输出
            
            BufferedReader sin = new BufferedReader(
                    new InputStreamReader(System.in));//系统标准输入
            
            System.out.println("Client:"+clientnum+is.readLine());//显示从客户端读入的对象，在这里等待客户端输入
            
            line=sin.readLine();
            //前面是初始化
            while(!line.equals("bye")) {
                os.println(line);//向客户端输出该字符串
                os.flush();//刷新，让客户端接收到
                System.out.println("Server:"+line);//显示服务端读入的字符
                System.out.println("Client:"+clientnum+is.readLine());//再次从客户端读入字符串
                line=sin.readLine();//从服务端读入字符
            }
            os.close();
            is.close();
            socket.close();
                    
        }catch(Exception e) {
            System.out.println("Error:"+e);
        }
    }
}

客户端：

import java.net.*;
import java.io.*;
public class TalkClient{

    public static void main(String args[]){
        try {
            Socket socket = new Socket("127.0.0.1",4700);
            System.out.print("已连接成功,");
            new Thread(new ClientThread(socket)).start();
            new Thread(new ClientThread2(socket)).start();
        }catch(Exception e) {
            System.out.println("Error"+e);
        }
        
}
}

客户端线程1：

import java.io.*;
import java.net.*;
public class ClientThread extends Thread{
    Socket socket;
    String line;
    public ClientThread(Socket socket) {
        this.socket = socket;

    }
    public void run(){
        try {
            BufferedReader is = new BufferedReader(new InputStreamReader(System.in));
            PrintWriter out = new PrintWriter(socket.getOutputStream());
            while(true) {
                line = is.readLine();
                out.println(line); //向服务器输入；
                out.flush();
            }
        }catch(Exception e){
            System.out.println("Error:"+e);
        }
    }
}

客户端线程2：

import java.io.*;
import java.net.*;
public class ClientThread2 extends Thread{
    Socket socket;

    public ClientThread2(Socket socket) {
        this.socket = socket;
    }
    public void run(){
        try {
            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            while(true) {
                String line = in.readLine();
                System.out.println(line); 
            }
        }catch(Exception e){
            System.out.println("Error:"+e);
        }
    }
}

展示结果：