Quartz之QuartzInitializerListener

问题:我想在WEB容器启动时就执行任务怎么办呢 
Quartz:使用QuartzInitializerListener就可办到了 
请注意它的优先级别比QuartzInitializerServlet要高 
在web.xml中可配置的参数如下: 
如： 

Java代码   

1. <context-param>  
2.          <param-name>quartz:config-file</param-name>  
3.          <param-value>/quartz.properties</param-value>  
4. </context-param>  

以下二者参数可代表都是同一个意思 
quartz:config-file                                                       或者 config-file 
quartz:shutdown-on-unload                                       或者  shutdown-on-unload 
quartz:wait-on-shutdown 
quartz:start-on-load                                                  或者   start-scheduler-on-load 
quartz:start-delay-seconds                                        或者   start-delay-seconds 
quartz:servlet-context-factory-key                              或者   servlet-context-factory-key 
默认值为:org.quartz.impl.StdSchedulerFactory.KEY 
quartz:scheduler-context-servlet-context-key              或者 scheduler-context-servlet-context-key 
以上参数都是根据QuartzInitializerListener源码得来的 
QuartzInitializerListener源码如下： 

Java代码   

1. package org.quartz.ee.servlet;  
2.   
3. import javax.servlet.ServletContext;  
4. import javax.servlet.ServletContextEvent;  
5. import javax.servlet.ServletContextListener;  
6. import org.quartz.Scheduler;  
7. import org.quartz.impl.StdSchedulerFactory;  
8. import org.slf4j.Logger;  
9. import org.slf4j.LoggerFactory;  
10.   
11. public class QuartzInitializerListener implements ServletContextListener {  
12.       
13.     public static final String QUARTZ_FACTORY_KEY = "org.quartz.impl.StdSchedulerFactory.KEY";  
14.     private boolean performShutdown;  
15.     private boolean waitOnShutdown;  
16.     private Scheduler scheduler;  
17.     private final Logger log;  
18.   
19.     public QuartzInitializerListener() {  
20.         this.performShutdown = true;  
21.         this.waitOnShutdown = false;  
22.   
23.         this.scheduler = null;  
24.   
25.         this.log = LoggerFactory.getLogger(super.getClass());  
26.     }  
27.   
28.     public void contextInitialized(ServletContextEvent sce) {  
29.         this.log  
30.                 .info("Quartz Initializer Servlet loaded, initializing Scheduler...");  
31.   
32.         ServletContext servletContext = sce.getServletContext();  
33.         try {  
34.             String configFile = servletContext  
35.                     .getInitParameter("quartz:config-file");  
36.             if (configFile == null)  
37.                 configFile = servletContext.getInitParameter("config-file");  
38.             String shutdownPref = servletContext  
39.                     .getInitParameter("quartz:shutdown-on-unload");  
40.             if (shutdownPref == null)  
41.                 shutdownPref = servletContext  
42.                         .getInitParameter("shutdown-on-unload");  
43.             if (shutdownPref != null) {  
44.                 this.performShutdown = Boolean.valueOf(shutdownPref)  
45.                         .booleanValue();  
46.             }  
47.             String shutdownWaitPref = servletContext  
48.                     .getInitParameter("quartz:wait-on-shutdown");  
49.             if (shutdownPref != null)  
50.                 this.waitOnShutdown = Boolean.valueOf(shutdownWaitPref)  
51.                         .booleanValue();  
52.   
53.             StdSchedulerFactory factory;  
54.   
55.             if (configFile != null)  
56.                 factory = new StdSchedulerFactory(configFile);  
57.             else {  
58.                 factory = new StdSchedulerFactory();  
59.             }  
60.   
61.             this.scheduler = factory.getScheduler();  
62.   
63.             String startOnLoad = servletContext  
64.                     .getInitParameter("quartz:start-on-load");  
65.             if (startOnLoad == null) {  
66.                 startOnLoad = servletContext  
67.                         .getInitParameter("start-scheduler-on-load");  
68.             }  
69.             int startDelay = 0;  
70.             String startDelayS = servletContext  
71.                     .getInitParameter("quartz:start-delay-seconds");  
72.             if (startDelayS == null)  
73.                 startDelayS = servletContext  
74.                         .getInitParameter("start-delay-seconds");  
75.             try {  
76.                 if ((startDelayS != null) && (startDelayS.trim().length() > 0))  
77.                     startDelay = Integer.parseInt(startDelayS);  
78.             } catch (Exception e) {  
79.                 this.log  
80.                         .error("Cannot parse value of 'start-delay-seconds' to an integer: "  
81.                                 + startDelayS + ", defaulting to 5 seconds.");  
82.                 startDelay = 5;  
83.             }  
84.   
85.             if ((startOnLoad == null)  
86.                     || (Boolean.valueOf(startOnLoad).booleanValue()))  
87.                 if (startDelay <= 0) {  
88.                     this.scheduler.start();  
89.                     this.log.info("Scheduler has been started...");  
90.                 } else {  
91.                     this.scheduler.startDelayed(startDelay);  
92.                     this.log.info("Scheduler will start in " + startDelay  
93.                             + " seconds.");  
94.                 }  
95.             else {  
96.                 this.log  
97.                         .info("Scheduler has not been started. Use scheduler.start()");  
98.             }  
99.   
100.             String factoryKey = servletContext  
101.                     .getInitParameter("quartz:servlet-context-factory-key");  
102.             if (factoryKey == null)  
103.                 factoryKey = servletContext  
104.                         .getInitParameter("servlet-context-factory-key");  
105.             if (factoryKey == null) {  
106.                 factoryKey = "org.quartz.impl.StdSchedulerFactory.KEY";  
107.             }  
108.   
109.             this.log  
110.                     .info("Storing the Quartz Scheduler Factory in the servlet context at key: "  
111.                             + factoryKey);  
112.   
113.             servletContext.setAttribute(factoryKey, factory);  
114.   
115.             String servletCtxtKey = servletContext  
116.                     .getInitParameter("quartz:scheduler-context-servlet-context-key");  
117.             if (servletCtxtKey == null)  
118.                 servletCtxtKey = servletContext  
119.                         .getInitParameter("scheduler-context-servlet-context-key");  
120.             if (servletCtxtKey != null) {  
121.                 this.log  
122.                         .info("Storing the ServletContext in the scheduler context at key: "  
123.                                 + servletCtxtKey);  
124.   
125.                 this.scheduler.getContext().put(servletCtxtKey, servletContext);  
126.             }  
127.         } catch (Exception e) {  
128.             this.log.error("Quartz Scheduler failed to initialize: "  
129.                     + e.toString());  
130.             e.printStackTrace();  
131.         }  
132.     }  
133.   
134.     public void contextDestroyed(ServletContextEvent sce) {  
135.         if (!this.performShutdown) {  
136.             return;  
137.         }  
138.         try {  
139.             if (this.scheduler != null)  
140.                 this.scheduler.shutdown(this.waitOnShutdown);  
141.         } catch (Exception e) {  
142.             this.log.error("Quartz Scheduler failed to shutdown cleanly: "  
143.                     + e.toString());  
144.             e.printStackTrace();  
145.         }  
146.   
147.         this.log.info("Quartz Scheduler successful shutdown.");  
148.     }  
149. }