基于Socket和ServerSocket实现通信

1. 服务器端：

package socketClient;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/** * 分发数据的服务端 * @author Heying * */
public class Server {
    private ServerSocket serversocket; // 服务端的socket
    private ExecutorService threadPoll; // 线程池
    private List<PrintWriter> allOut; // 广播集合
    private Queue<String> messageQueue; // 放客户端的数据

    /* * 1.初始化端口 * 2.初始化线程池 * 3.初始化客户端的数据流 * 4.初始化消息队列 */
    public Server() {
        try {
            serversocket = new ServerSocket(8086); //1.
            threadPoll = Executors.newCachedThreadPool(); //2. 初始化线程池
            allOut = new ArrayList<PrintWriter>(); //3.初始共享集合
            messageQueue = new LinkedList<String>(); //4. 初始化消息队列
        } catch (IOException e) {
            e.printStackTrace();
            System.err.println("初始化失败！！！");
        }
    }

    /* * 启用客户端的方法 */
    public void start(){
        try {
            Runnable sendHandler = new sendMessageHandler();
            Thread t = new Thread(sendHandler);
            t.setDaemon(true);
            t.start();

        while(true){
            System.out.println("等待客户端连接....");
            Socket socket = serversocket.accept();
            System.out.println("一个客户端连接！");
            /* * 当一个客户端连接后，启动一个线程 * 将该客户端的Socket传入。 * 使用线程来并发处理客户端的交互。 * */
            Runnable handler = new ClientHandler(socket);
            threadPoll.execute(handler); // 将任务交给线程池去处理

// Thread t1 = new Thread(handler);
// t1.start();
        }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /** * 向共享集合中添加新的输出流 */
    public synchronized void addOut(PrintWriter out){
        allOut.add(out);
    }
    /** * 将给定的输出流从共享集合中删除 * @param out */
    public synchronized void removeOut(PrintWriter out){
        allOut.remove(out);
    }
    public synchronized void sendMessageToAllClent(String message){
        for(PrintWriter out:allOut){
            out.println(message);
        }
}

    public static void main(String[] args) {
        new Server().start();
    }

    /** * */
    class ClientHandler implements Runnable{
        private Socket socket;

        public ClientHandler(Socket socket) {
            this.socket = socket;
        }

        @Override
        public void run() {
            PrintWriter pw = null;
            try {
                OutputStream os = socket.getOutputStream();// 创建客户端输出流 得到数据广播
                OutputStreamWriter osp = new OutputStreamWriter(os,"UTF-8");
                pw = new PrintWriter(osp,true);

                // 1.将客户端的输出流放入共享集合
                addOut(pw);
                System.out.println("当前在线人数:"+allOut.size());

                // 2.读取客户端的数据
                InputStream is = socket.getInputStream();
                InputStreamReader isr = new InputStreamReader(is,"UTF-8");
                BufferedReader br = new BufferedReader(isr);

                String message = null;  
                while( (message = br.readLine())!= null){
                    messageQueue.offer(message);
                }

            } catch (IOException e) {
                e.printStackTrace();
            } finally{
                try {
                System.out.println("一个客户端下线！！！");
                // 客户端从队列中删除
                removeOut(pw);
                System.out.println("在线人数>>> "+allOut.size());
                socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

        }

    }

    /** * 接受到客户端的信息，然后转发 * @author Heying * */
    class sendMessageHandler implements Runnable{

        @Override
        public void run() {
            String message = null;
            while(true){
                if(messageQueue.size() > 0){
                    message = messageQueue.poll();
                    sendMessageToAllClent(message);//转发
                }else{
                    try {
                        Thread.sleep(100);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }

    }

}

2.客户端

package socketClient;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.Scanner;

/** * 接受发送的客户端 * @author Heying * */
public class Client {
    private Socket socket;
    /* * 初始化 * 1.服务器的IP地址 * 2.服务器的端口 */
    public Client() {
        try {
          socket = new Socket("localhost",8086); // 主机和端口
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /* * 启用客户端 */
    public void start(){
        try {
            Runnable hadler = new GetServerMessageHandler();
            Thread t = new Thread(hadler);
            t.start();

            OutputStream out = socket.getOutputStream(); //获取服务端发送的数据流（输出流）
            OutputStreamWriter opsw = new OutputStreamWriter(out,"UTF-8"); // 直接流-> 字符流 设置字符集
            PrintWriter pw = new PrintWriter(opsw, true);

            Scanner sc = new Scanner(System.in); // 设置键盘输入
            while(true){
                String message = sc.nextLine(); // 读取一行输入
                pw.println(message); // 
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        new Client().start();
    }
    /** * 获取服务器发送过来的数据 * @author Heying * */
    class GetServerMessageHandler implements Runnable{

        @Override
        public void run() {
            try {
                InputStream in = socket.getInputStream(); // 获取到输入流 获取服务器的数据
                InputStreamReader isr = new InputStreamReader(in,"UTF-8"); // 字符集
                BufferedReader br = new BufferedReader(isr);

                String message = null;
                while((message = br.readLine()) != null ){
                    System.out.println(">>> "+message);
                }

            } catch (Exception e) {
                e.printStackTrace();
            }
        } 

    }
}