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
>
