企业定时任务调度器Quartz，定时查询数据库

    看到楼下各位兄弟的批评指正后，确实对我很有启发，任务如果都以配置的形式出现，在项目中是很利于维护的，所以，稍作修改，呵呵。

首先要做QuartzJob定时任务类了，这个类要实现的是Job接口，然后重写execute方法，方法中就是执行你具体要做的事情了。不过首先需要一个配置文件，里面定义了一些参数，是Quartz的一些配置。配置文件如下

#============================================================================
# Configure Main Scheduler Properties  
#============================================================================
org.quartz.scheduler.instanceName = QuartzScheduler
org.quartz.scheduler.instanceId = AUTO

#============================================================================
# Configure ThreadPool  
#============================================================================
org.quartz.threadPool.class = org.quartz.simpl.SimpleThreadPool
org.quartz.threadPool.threadCount = 3
org.quartz.threadPool.threadPriority = 5

#===============================================================
#Configure JobStore
#===============================================================
org.quartz.jobStore.misfireThreshold = 60000
org.quartz.jobStore.class = org.quartz.simpl.RAMJobStore

#============================================================================
# Configure Plugins 
#============================================================================
#org.quartz.plugin.triggHistory.class = org.quartz.plugins.history.LoggingJobHistoryPlugin
org.quartz.plugin.jobInitializer.class = org.quartz.plugins.xml.JobInitializationPlugin
org.quartz.plugin.jobInitializer.fileName = conf/quartz_jobs.xml
org.quartz.plugin.jobInitializer.overWriteExistingJobs = true
org.quartz.plugin.jobInitializer.failOnFileNotFound = true
org.quartz.plugin.jobInitializer.scanInterval = 60

即使做成配置，这个类也必须要有，一定会有个Job类，专门做数据分析，有的朋友说配置文件搞定所有，不现实，
好了，这就是配置文件，接下来我们就要做这个计划类了，这个类执行的是去源数据库中查询数据，并插入目标数据库中，并且不允许有重复。代码如下

package com.bj58.job.servlet;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.quartz.Job;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;

import com.bj58.job.utils.ConnectionFactory_DB_dest;
import com.bj58.job.utils.ConnectionFactory_DB_src;

/**
 * 定时任务类
 * @author [email protected]
 * Jun 8, 2010
 *
 */
public class QuartzJob implements Job {
	private static final Log log = LogFactory.getLog(Job.class);
	private static final String findSql_src = "select PortalId from t_portalinfo";
	private static final String findSql_dest = "select userId from t_user";
	private static final String insertSql_dest = "insert into t_user(userId) values (?)";
	
	/**
	 * 执行任务方法
	 */
	@Override
	public void execute(JobExecutionContext context) throws JobExecutionException {
		Connection conn_db_src = ConnectionFactory_DB_src.getConnection();
		Connection conn_db_dest = ConnectionFactory_DB_dest.getConnection();
		PreparedStatement pstmt_src = null;
		PreparedStatement pstmt_dest = null;
		ResultSet rs_src = null;
		ResultSet rs_dest = null;
		try {
			pstmt_src = conn_db_src.prepareStatement(findSql_src);
			rs_src = pstmt_src.executeQuery();

			pstmt_dest = conn_db_dest.prepareStatement(findSql_dest);
			rs_dest = pstmt_dest.executeQuery();
			pstmt_dest = conn_db_dest.prepareStatement(insertSql_dest);
			
			while(rs_dest.next()) { //第二次或第n次入库，第一次入库的话rs_dest没有结果，所以此段操作都不执行
				String userId = rs_dest.getString(1);
				while (rs_src.next()) {
					String protalId = rs_src.getString(1);
					if(userId.equals(protalId)) { //如果两个结果相同，则不进行入库
						break;
					} else {
						pstmt_dest.setString(1, protalId);
						pstmt_dest.execute();
					}
				}
			}
			
			while (rs_src.next()) { //如果是第一次入库
				String protalId = rs_src.getString(1);
				pstmt_dest.setString(1, protalId);
				pstmt_dest.execute();
				
			}
			log.info("存储数据...");
		} catch (SQLException e) {
			log.info("存储数据出现异常...");
			e.printStackTrace();
		} finally {
			ConnectionFactory_DB_dest.free(rs_dest, pstmt_dest, conn_db_dest);
			ConnectionFactory_DB_src.free(rs_src, pstmt_src, conn_db_src);
			log.info("数据库连接已经关闭...");
		}

	}
}

这里一次性查出了源数据库中所有字段，因为源数据库表中的数据最多不会超过10000条，我在做测试的时候，在本机上发现一次查询10W条也不会出现结果集溢出情况，所以这里就忽略这个问题了。

然后需要这么个配置文件quartz_jobs.xml，内容如下

<?xml version="1.0" encoding="UTF-8"?>
<quartz>
	<job>
		<job-detail>
			<name>PortalInfoJob</name>
			<group>PortalInfo</group>
			<job-class>com.bj58.portalcrm.web.job.PortalInfoJob</job-class>
		</job-detail>
		<trigger>
			<cron>
				<name>PORTALINFO</name>
				<job-name>PortalInfoJob</job-name>
				<job-group>PortalInfo</job-group>
				<cron-expression>0 0 1 * * ?</cron-expression>
			</cron>
		</trigger>
	</job>
</quartz>

ok，最后就是web.xml文件配置一下，Quartz提供了个初始化的Servlet，呵呵，内容如下

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" 
	xmlns="http://java.sun.com/xml/ns/j2ee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
	http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
	
    <welcome-file-list>
      	<welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
  
    <!-- Quartz配置计划 -->
    <servlet>   
         <servlet-name>QuartzInitializer</servlet-name>   
         <servlet-class>org.quartz.ee.servlet.QuartzInitializerServlet</servlet-class>   
         <load-on-startup>1</load-on-startup>   
         <init-param>   
             <param-name>config-file</param-name>   
             <param-value>/quartz.properties</param-value>   
         </init-param>   
         <init-param>   
             <param-name>shutdown-on-unload</param-name>   
             <param-value>true</param-value>   
         </init-param>   
	</servlet>
</web-app>

这样就搞定了，