Java Socket使用小技巧

     这几天一直在写一个GPS+SMS模式的定位程序，流程大致是这样，首先接收用户的定位请求，然后把这个请求按照制定的协议用xml包装，用Socket发给短信服务器，短信服务器发送指令至终端，终端反回经续度，然后再把这个经纬度送到GIS系统，获取地理信息位置描述，最后把这个结果返回给客户端。

   但是因为网络或其它的原因，短信服务器经常没有响应，因此必须不停的建接，直到这个连接被建立。

client code

package com.tdt.client;

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;
import java.util.Timer;
import java.util.TimerTask;

import javax.net.SocketFactory;

public class Client {
	private static Client client;
	private static Timer timer = new Timer();
	private static String host="localhost";
	private int port =5555;
	private static Socket socket;
	
	private Client() throws UnknownHostException, IOException {
		socket = SocketFactory.getDefault().createSocket(host, port);
		System.out.println("connection "+host+":"+port+" success!");
		
	}
	//获得输出对象
	private PrintWriter getWriter(Socket socket) throws IOException {
		OutputStream socketOut = socket.getOutputStream();
		return new PrintWriter(socketOut,true);
	}
	//获得读取对象
	private BufferedReader getReader(Socket socket) throws IOException {
		InputStream socketIn = socket.getInputStream();
		return new BufferedReader(new InputStreamReader(socketIn));
	}
	//会话
	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)  {
				if(msg.equalsIgnoreCase("bye")) {
					System.out.println("会话结束");
					break;
				}
				pw.println(msg);
				System.out.println("server:"+br.readLine());
				
			}
		}catch(IOException e) {
			e.printStackTrace();
		}finally {
			try {if (socket !=null)socket.close();} catch(IOException e) {
				e.printStackTrace();
			}
		}
	}
	
	//实例化client
	public static void instance() {
		if(client ==null) {
			try {
				client = new Client();
			} catch (Exception e) {
				System.err.println(e.getMessage() +":"+host);
			}
		}
	}
	
	public static void main(String[] args) throws Exception{
		if(args.length !=0) {
			host = args[0].toString();
		}
		//用阻塞方法或计时器不断与服务连接，直到连接被建立
	/*	while(true) {
			System.out.println("开始实例化");
			instance();
			if(client !=null)
				break;
			Thread.sleep(1000 *5);
		} 
		client.talk(); */
		timer.schedule(new TimerTask() {
			public void run() {
				if(client ==null) {
					instance();
				} else {
					timer.cancel();
					try {
						client.talk();
					} catch (IOException e) {System.err.println("IO流异常"); }
				}
			}
		}, 0, 1000 * 5);
	}
}

 

 

server code

package com.tdt.server;

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 Server {
	private ServerSocket serverSocket = null;
	private Socket socket = null;
	private int port =5555;
	public Server() {
		try {
			serverSocket = new ServerSocket(port);
			System.out.println("服务器端监听"+port+"端口");
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	//获取输入流读取对象
	public BufferedReader getReader(Socket st) throws IOException {
		InputStream socketIn = st.getInputStream();
		return new BufferedReader(new InputStreamReader(socketIn));
	}
	//获取输出对象
	public PrintWriter getWriter(Socket st) throws IOException{
		OutputStream out = st.getOutputStream();
		return new PrintWriter(out,true);
	}
	public String echo(String msg) {
		return "通讯测试，由服务器端发出";
	}
	
	public void service() {
		try {
			socket=serverSocket.accept();
			System.out.println("有客户端连接");
			System.out.println("IP="+socket.getInetAddress()+":"+socket.getPort());
		} catch (IOException e1) {
			e1.printStackTrace();
		}
		while(true) {
			try {
				BufferedReader br = getReader(socket);
				PrintWriter pw = getWriter(socket);
				
				String msg = null;
				while((msg =br.readLine()) !=null) {
					System.out.println("client:"+msg);
					String echoMsg = echo(msg);
					pw.println(echoMsg);
					System.out.println("服务器回应:"+echoMsg);
					
					if(msg.equalsIgnoreCase("bye")) {
						break;
					}
				}
			}catch(IOException e) {
				e.printStackTrace();
				System.out.println("IO流异常");
			} finally {
				try {
					if(serverSocket!=null) serverSocket.close();
					if(socket !=null) socket.close();
					System.out.println("通讯测试结束，服务器端关闭");
					System.exit(0);
				} catch(IOException e) {e.printStackTrace();}
			}
		}
	}
	
	public static void main(String[] args) {
		//启动服务器
		new Server().service();
	}
}

 

 

    先启动client，让它不停的去连服务端，当然了，服务器端没有启动肯定没法与服务器建立连接

启动服务器端