给web 服务器后台加线程

一。新建一个servlet{

package com.ibox.init;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.ibox.util.ServerTimer;

public class InitServlet extends HttpServlet {
 public InitServlet() {
  super();
 }
 public void destroy() {
  super.destroy(); // Just puts "destroy" string in log
  // Put your code here
 }
 public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
  doPost(request, response);
 }
 public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
 }
 public void init() throws ServletException {
  
  ServletContext application = getServletConfig().getServletContext();
  String realpath = this.getServletContext().getRealPath("/");
  new ServerTimer(application,realpath).start();
  
 }
}

}
二。在web.xml配这个servlet{

  <!-- 初始化信息 -->
  <servlet>
    <servlet-name>InitValue</servlet-name>
    <servlet-class>com.ibox.init.InitServlet</servlet-class>
    <load-on-startup>7</load-on-startup>
  </servlet>

}
三。新建serverTimer线程类｛

package com.ibox.util;
import java.util.Date;
import javax.servlet.ServletContext;
public class ServerTimer extends Thread {
 ServletContext application = null;
 String realpath = "";
 int step = 1000;
 public ServerTimer(ServletContext application,String realpath){
  this.application = application;
  this.realpath = realpath;
 }
 public ServerTimer(ServletContext application,String realpath,int step){
  this.application = application;
  this.realpath = realpath;
  this.step = step;
 }
 public void run(){
  while(true){
   ServerTimerInterface st = new GetServetTime();
   st.timerStart(application);
   try{
    Thread.sleep(step);
   }catch (Exception e) {
    e.printStackTrace();
   }
  }
 }
}

｝
四。新建执行接口｛

package com.ibox.util;
import javax.servlet.ServletContext;

public interface ServerTimerInterface {
 public void timerStart();
 public void timerStart(ServletContext application);
}

｝
五。实现执行方法｛

package com.ibox.util;
import java.util.Date;
import javax.servlet.ServletContext;

public class GetServetTime implements ServerTimerInterface {
 public void timerStart() {
 }
 public void timerStart(ServletContext application) {
//  String cpumsg = new GetCPU().getCpu(realpath);
  Date date = new Date();
  int year = date.getYear() + 1900;
  int month = date.getMonth()+1;
  int d = date.getDate();
  int day = date.getDay();
  int hour = date.getHours();
  int min = date.getMinutes();
  int sec = date.getSeconds();
  String timeStr = ""+year+" "+month+" "+" "+addZero(hour)+":"+addZero(min)+":"+addZero(sec);
  application.setAttribute("nowtime", timeStr);
  
 }
 
 private String addZero(int a){
  String s = "";
  if(a < 10){
   s = "0"+a;
  }else{
   s = ""+a;
  }
  return s;
 }
}

｝
本例为获取服务器时间并存入application内
本例只开了一个线程，基本够用，如需更多线程，要改源码
（按提示顺序建类会报错，但都建完就好了，也可倒序建）
参考：无，个人项目用