Java实现服务器端对多个客户端请求响应

首先，创建一个服务器端的套接字，并规定套接字监听的端口：

ServerSocket serverSocket = new ServerSocket(8001);

然后，等待客户端通过端口8001的请求：

Socket socket=serverSocket.accept();

接下来创建客户端接收到的套接字的输入输出流，并将输入输出流转化成扫描器和写入器：

InputStream inputStream = incomingSocket.getInputStream();
OutputStream outputStream = incomingSocket.getOutputStream();
//将输入流转化为扫描器，输出流转化为写入器
Scanner inScanner=new Scanner(inputStream);
PrintWriter outPrintWriter= new PrintWriter(outputStream, true);

接下来就可以运用扫描器获得客户端传来的数据，并运用写入器将传来的数据发送给客户端：

String backString=inScanner.next();
outPrintWriter.println("you give me:"+backString);

然后，将每一个连接创建一个新的线程，独立运行。

运用命令行的telnet命令就可以连接上客户端：

可以多次创建连接：

一下为完整代码：

<span style="font-size: 14px; font-family: Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);"></span><pre name="code" class="java">package server;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;

public class ThreadEchoServer {

	public static void main(String[] args) {
		// TODO Auto-generated method stub

		try {
			int i=1;
			ServerSocket serverSocket = new ServerSocket(8001);
			while(true){
				//等待客户端通过端口8001请求的连接
				Socket socket=serverSocket.accept();
				
				System.out.println("spawning"+i);
				Runnable runnable= new ThreadEchoHandler(socket);
				Thread thread = new Thread(runnable);
				thread.start();
				i++;
				
			}
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}

}

class ThreadEchoHandler implements Runnable
{
	private Socket incomingSocket;
	
	public ThreadEchoHandler(Socket in){
		incomingSocket=in;
	}
	
	public void run(){
		try {
			try {
				//建立套接字的输入输出流
				InputStream inputStream = incomingSocket.getInputStream();
				OutputStream outputStream = incomingSocket.getOutputStream();
				//将输入流转化为扫描器，输出流转化为写入器
				Scanner inScanner=new Scanner(inputStream);
				PrintWriter outPrintWriter= new PrintWriter(outputStream, true);
				
				//运用写入器的println函数向客户端输出字符串
				outPrintWriter.println("welcome!");
				
				//将客户端传输的数据发送回去，如果客户端输入的数据为bye，则断开连接
				boolean flag=false;
				while(!flag&&inScanner.hasNext()){
					String backString=inScanner.next();
					outPrintWriter.println("you give me:"+backString);
					if(backString.trim().equals("bye")){
						flag=true;
					}
				}
			} finally {
				// TODO: handle exception
				//关闭套接字（很重要，防止造成资源浪费）
				incomingSocket.close();
			}
		} catch (IOException e) {
			// TODO: handle exception
		}
	}
}

<span style="font-size: 14px; font-family: Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);">本文参考《Java核心技术卷II》</span>