座IO理解力

package com.bio.demo.Server;

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;

import com.bio.demo.Server.handler.TimerServerHandler;

/**
 * @author zhouxuejun
 *
 * @date 2014年10月20日 下午7:08:58
 */
public class TimeServer {
	
     public static ServerSocket server=null;
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		try {
			server=new ServerSocket(8080);
			Socket socket=null;
			while(true){
				socket=server.accept();
				new Thread(new TimerServerHandler(socket)).start();
			}
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
       
	}

}

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;

/**
 * @author zhouxuejun
 *
 * @date 2014年10月20日 下午7:17:28
 */
public class TimerServerHandler implements Runnable {

	 private Socket socket;
	 public  TimerServerHandler(Socket socket) {
		// TODO Auto-generated constructor stub
		 this.socket=socket;
	}
	/* (non-Javadoc)
	 * @see java.lang.Runnable#run()
	 */
	@Override
	public void run() {
		// TODO Auto-generated method stub
      BufferedReader in=null;
      PrintWriter out=null;
      try {
		in=new BufferedReader(new InputStreamReader(this.socket.getInputStream()));
		out=new PrintWriter(this.socket.getOutputStream());
		String body=null;
		String tag=null;
		while(true){
		body=in.readLine();
		if(null==body)
			 break;
        out.print(body+"_return"); 
		}
	} catch (IOException e) {
		// TODO Auto-generated catch block
		if(null!=in){
			try {
				in.close();
			} catch (IOException e1) {
				// TODO Auto-generated catch block
				e1.printStackTrace();
			}
		}
		if(null!=out){
			out.close();
			out=null;
		}
		if(null!=this.socket){
			try {
				this.socket.close();
			} catch (IOException e1) {
				// TODO Auto-generated catch block
				e1.printStackTrace();
			}
			this.socket=null;
		}
		e.printStackTrace();
	}
	}

}