Quartz 框架快速入门（三）

在前面两篇文章中简单介绍了在java应用程序中如何使用Quartz框架，这一篇中我们将看到如何在web环境下通过配置文件来完成Quartz的后台作业调度，而不必手工去创建Trigger和Scheduler，其步骤如下：
首先创建一个Web项目，将quartz-1.6.0.jar,以及lib目录下面core下所有jar，optional目录下的所有commons-beanutils.jar和commons-digester-1.7.jar，build目录下的jta.jar都放入Web项目的WEB-INF"lib目录下。
创建一个简单的job类HelloWorld，它的功能很简单，就是输出当前的时间，代码如下：
package com.vista.quartz;

import java.util.Date;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import org.quartz.Job;

import org.quartz.JobExecutionContext;

import org.quartz.JobExecutionException;

public class Helloworld implements Job

{

private static Log logger = LogFactory.getLog(Helloworld.class);//日志记录器

public Helloworld()

{

}

public void execute(JobExecutionContext context) throws JobExecutionException

{

logger.info("Hello World! - " + new Date());

}

}

然后按照上一篇文章《Quartz 框架快速入门（二）》中所讲述的内容编写quartz.properties文件。如果启动项目的时候，Quartz没有在工程中找到该文件，就会从自己的jar包下面读取其默认的properties文件，其内容如下
#============================================================================

# 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 = 5

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.fileNames = jobs.xml

org.quartz.plugin.jobInitializer.overWriteExistingJobs = true

org.quartz.plugin.jobInitializer.failOnFileNotFound = true

org.quartz.plugin.jobInitializer.scanInterval = 10

org.quartz.plugin.jobInitializer.wrapInUserTransaction = false

然后编写任务配置文件jobs.xml，内容如下:
<?xml version='1.0' encoding='utf-8'?>

<quartz xmlns="http://www.opensymphony.com/quartz/JobSchedulingData"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://www.opensymphony.com/quartz/JobSchedulingData

http://www.opensymphony.com/quartz/xml/job_scheduling_data_1_5.xsd"
version="1.5">

<job>

<job-detail>

<name>HelloWorld</name>

<group>DEFAULT</group>

<description>

A job that just for test

</description>

<job-class>

com.vista.quartz.Helloworld

</job-class>

<volatility>false</volatility>

<durability>false</durability>

<recover>false</recover>

</job-detail>

<trigger>

<simple>

<name>HelloTrigger1</name>

<group>DEFAULT</group>

<job-name>HelloWorld</job-name>

<job-group>DEFAULT</job-group>

<start-time>2008-09-03T15:56:30</start-time>

<!-- repeat indefinitely every 10 seconds -->

<repeat-count>-1</repeat-count>

<repeat-interval>10000</repeat-interval>

</simple>

</trigger>

</job>

</quartz>

可以看到，在配置文件中把jobdetail和trigger都作了完整的定义，并组合成一个job。下面，我们把上面两个文件都放入/WEB-INF/classes目录下，然后按照api中的说明修改一下web.xml，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">
<servlet>

<servlet-name>QuartzInitializer</servlet-name>

<display-name>Quartz Initializer Servlet</display-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>

<welcome-file-list>

<welcome-file>index.jsp</welcome-file>

</welcome-file-list>

</web-app>

这样，在启动Tomcat的时候，QuartzInitializerServlet这个Servlet就会自动读取quartz.properties这个配置文件，并初始化调度信息，启动Scheduler。
启动tomcat后，就可以看到输出的结果: