1，socket编程小例
创建一个EchoServer和一个EchoClient类，EchoServer用于从监听从客户端输入的字符串，当客户端输入"bye"时停止
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package com.test.socket;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.OutputStream;import java.io.PrintWriter;import java.net.ServerSocket;import java.net.Socket;public class EchoServer {private int port = 8000;private ServerSocket serverSocket;public static void main(String[] args) throws IOException {new EchoServer().service();}public EchoServer() throws IOException {serverSocket = new ServerSocket(port);System.out.println("服务器启用");}public String echo(String msg) {return "echo: " + msg;}private PrintWriter getWriter(Socket socket) throws IOException {OutputStream socketOut = socket.getOutputStream();return new PrintWriter(socketOut, true);}private BufferedReader getReader(Socket socket) throws IOException {InputStream socketIn = socket.getInputStream();return new BufferedReader(new InputStreamReader(socketIn));}public void service(){while(true){Socket socket = null;try{socket = serverSocket.accept();System.out.println("new connection accepted "+ socket.getInetAddress() + ":" + socket.getPort());BufferedReader br = getReader(socket);PrintWriter pw = getWriter(socket);String msg = null;while((msg =br.readLine()) != null){//输入，读取客户端的输入System.out.println(msg);pw.println(echo(msg));//输出，返回到客户端if(msg.endsWith("bye")){break;}}}catch (Exception e) {e.printStackTrace();}finally{try{if(socket != null){socket.close();}}catch (Exception e) {e.printStackTrace();}}}}}?
package com.test.socket;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.OutputStream;import java.io.PrintWriter;import java.net.Socket;import java.net.UnknownHostException;public class EchoClient {private String host = "localhost";private int port = 8000;private Socket socket;public EchoClient() throws UnknownHostException, IOException {socket = new Socket(host,port);}public static void main(String[] args) throws UnknownHostException, IOException{new EchoClient().talk();}private PrintWriter getWriter(Socket socket)throws IOException{OutputStream socketOut = socket.getOutputStream();return new PrintWriter(socketOut,true);}private BufferedReader getReader(Socket socket)throws IOException{InputStream socketIn = socket.getInputStream();return new BufferedReader(new InputStreamReader(socketIn));}public void talk()throws IOException{try{BufferedReader br = getReader(socket);PrintWriter pw = getWriter(socket);BufferedReader localReader = new BufferedReader(new InputStreamReader(System.in));String msg = null;while((msg = localReader.readLine()) !=null ){//读取在管理控制台输入的字符串pw.println(msg);//向服务器端传送字符串System.out.println(br.readLine());//读取服务器端返回的字符串if(msg.equals("bye")){break;}}}catch (Exception e) {e.printStackTrace();}finally{try{socket.close();}catch (Exception e) {e.printStackTrace();}}}}?