java中timer在web.xml中的一个例子2021-11-26 23:54:41分三步 一、定时执行的任务类Daemon 二、扩展HttpServlet的servlet 三、配置web.xml文件 细节如下： 一、定时执行的任务类Daemon package com.resoft.recis.common.timer;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;import java.util.Timer;import java.util.TimerTask;import javax.servlet.ServletException;/** *//** * Function: * User : zxs_9999 * Date : */public class Daemon ...{ private static final Timer timer = new Timer(); // private static String sDBDriver = "com.ibm.db2.jcc.DB2Driver";// private static String url="jdbc:db2://127.0.0.1:50000/test"; // private static String user="db2"; // private static String password="db2"; private static String sDBDriver = "com.microsoft.jdbc.sqlserver.SQLServerDriver"; private static String url="jdbc:microsoft:sqlserver://127.0.0.1:1433;DatabaseName=test"; private static String user="sql"; private static String password="sql"; private static Connection conn = null; private static ResultSet rs = null; static...{ try ...{ Class.forName(sDBDriver); }catch(java.lang.ClassNotFoundException e)...{ System.out.println("in Jdbc() , ClassNotFoundException"); e.printStackTrace(); }catch(Exception e)...{ System.out.println("in Jdbc() , after ClassNotFoundException's Exception"); e.printStackTrace(); } } public static void start()...{ timer.scheduleAtFixedRate(new TimerTask()...{ public void run()...{ Calendar calendar = Calendar.getInstance(); int hour = calendar.get(Calendar.HOUR_OF_DAY); System.out.println("run hour: "+hour); //20点以后再执行 if(hour>=20 && hour<=22)...{ ResultSet RS = executeQuery("SELECT * FROM OrgMng"); Date workdate=null; try ...{ rs.next(); workdate=rs.getDate("workdate"); RS.close(); executeUpdate("update OrgMng set workdate ='"+changeDate(workdate)+"'"); } catch (Exception e) ...{ // TODO: handle exception System.out.println("in start() , Exception"); e.printStackTrace(); } } } } ,0,1000*60*60*2);//两个小时1000*60*60*2 自动执行一次 System.out.println("timer 自动更新日期程序启动..."); } public static ResultSet executeQuery(String sql) ...{ rs = null; try ...{ conn= DriverManager.getConnection(url,user,password); Statement stmt = conn.createStatement(); rs = stmt.executeQuery(sql); }catch(SQLException ex) ...{ System.out.println("in executeQuery , SQLException"); ex.printStackTrace(); }catch(Exception e)...{ System.out.println("in executeQuery , after SQLException's Exception"); e.printStackTrace(); } return rs; } public static void executeUpdate(String sql) ...{ try ...{ //conn = DriverManager.getConnection(url); conn= DriverManager.getConnection(url,user,password); Statement stmt = conn.createStatement(); stmt.executeUpdate(sql); }catch(SQLException ex) ...{ System.out.println("in executeUpdate , SQLException"); ex.printStackTrace(); }catch(Exception e)...{ System.out.println("in executeUpdate , after SQLException's Exception"); e.printStackTrace(); } } public static String changeDate(Date workdate)...{ String temp=null; try...{ SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); Calendar calendar=Calendar.getInstance(); calendar.setTime(workdate); calendar.add(Calendar.DATE, 1); temp=sdf.format(calendar.getTime()); System.out.println("workdate is "+temp); }catch(Exception e)...{ System.out.println("in changeDate ,Exception"); e.printStackTrace(); } return temp; } public static void main(String[] args) throws ServletException ...{ Daemon.start(); }} 二、扩展HttpServlet的servlet package com.resoft.recis.common.timer;import javax.servlet.http.HttpServlet;import javax.servlet.ServletException;/** *//** * User: zxs_9999 * Date: * Time: */public class HttpImportDaemon extends HttpServlet...{ public void init() throws ServletException ...{ Daemon.start(); }} 三、配置web.xml文件 <servlet> <servlet-name>workdate</servlet-name> <display-name>chage workdate</display-name> <servlet-class> com.resoft.recis.common.timer.HttpImportDaemon </servlet-class> <load-on-startup /> </servlet> <servlet-mapping> <servlet-name>workdate</servlet-name> <url-pattern>/*</url-pattern> </servlet-mapping> 上一篇：使用CentOS/RHEL防火墙下一篇：批处理文件