建立简单的服务器端程序

  参考自core java

 

package com.lujinhong.corejava;



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 EchoServer {



	public static void main(String[] args) {

		

		try {

			ServerSocket serverSocket = new ServerSocket(8019);

			Socket socket = serverSocket.accept();

			

			InputStream is = socket.getInputStream();

			OutputStream os = socket.getOutputStream();

			

			PrintWriter pw = new PrintWriter(os);

			Scanner sc = new Scanner(is);

			

			Boolean flag = false;

			String line = null;

			String exitString = "bye";

			

			while(!flag && sc.hasNextLine()){

				pw.println("Hello, type " + exitString + " to exit!");

				line = sc.nextLine();

				if(line.trim().equals(exitString)){

					flag = true;

				}else{

					pw.println("Hello, "+line);

				}

			}

			pw.close();

			sc.close();

			serverSocket.close();

		} catch (IOException e) {

			e.printStackTrace();

		}

	}

}

 

使用线程实现多个客户端同时访问：

 

package com.lujinhong.corejava;



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 MultiEchoServer {



	public static void main(String[] args) {

		try {

			ServerSocket serverSocket = new ServerSocket(8189);

			while (true) {

				Socket socket = serverSocket.accept();



				Runnable r = new ThreadedEchoHandler(socket);

				Thread thread = new Thread(r);

				thread.start();

			}



		} catch (IOException e) {

			e.printStackTrace();

		}



	}



}



class ThreadedEchoHandler implements Runnable {



	private Socket s = null;



	public ThreadedEchoHandler(Socket socket) {

		s = socket;

	}



	@Override

	public void run() {

		try {

			InputStream is = s.getInputStream();

			OutputStream os = s.getOutputStream();



			PrintWriter pw = new PrintWriter(os);

			Scanner sc = new Scanner(is);



			Boolean flag = false;

			String line = null;

			String exitString = "bye";



			while (!flag && sc.hasNextLine()) {

				pw.println("Hello, type " + exitString + " to exit!");

				line = sc.nextLine();

				if (line.trim().equals(exitString)) {

					flag = true;

				} else {

					pw.println("Hello, " + line);

				}

			}

			sc.close();

			pw.close();

		} catch (IOException e) {

			e.printStackTrace();

		}

	}

}

In this program, we spawn a separate thread for each connection. This approach is not satisfactory for highperformance servers. You can achieve greater server throughput by using features of the java.nio package. See www.ibm.com/developerworks/java/library/j-javaio for more information.