本文实例为大家分享了jcrontab简单入门，供大家参考，具体内容如下
创建一个javaweb项目
1、首先要下载jcrontab的相关jar包，jcrontab-2.0-rc0.jar。放到lib文件夹下。
2、在src下新建文件jcrontab.properties如下：
#crontab.xml
文件的目录，这个是作业调度规则
org.jcrontab.data.file =e:/eclipseworkspace/ademo/webcontent/web-inf/crontab.xml
#sax解析驱动类型
org.xml.sax.driver=org.apache.xerces.parsers.saxparser
#datasource文件类型
org.jcrontab.data.datasource=org.jcrontab.data.xmlsource
3、在web-inf下新建文件crontab.xml
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<?xml version="1.0" encoding="utf-8"?><crontab><crontabentry id="2014"><seconds>0,5,10,15,20,25,30,35,40,45,50,55</seconds><minutes>*</minutes><hours>*</hours><daysofmonth>*</daysofmonth><months>*</months><daysofweek>*</daysofweek><years>*</years><bussinesdays>true</bussinesdays><startdate></startdate><enddate></enddate><class>xu.crontab.crontab1</class><method>run</method><parameters></parameters><description></description></crontabentry></crontab> |
以上属性自己百度一下，<seconds>0,5,10,15,20,25,30,35,40,45,50,55</seconds>这个是秒数是5的倍数就调用作业
4、web.xml配置如下
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<?xml version="1.0" encoding="utf-8"?><web-app xmlns:xsi="http://www.w3.org/2001/xmlschema-instance"xmlns="http://xmlns.jcp.org/xml/ns/javaee"xsi:schemalocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"id="webapp_id" version="3.1"><display-name>ademo</display-name> <servlet><servlet-name>loadonstartupservlet</servlet-name><servlet-class>xu.crontab.loadcrontabservlet</servlet-class><init-param><param-name>properties_file</param-name><!--此处路径是绝对路径 --><param-value>e:\eclipseworkspace\ademo\src\jcrontab.properties</param-value></init-param><load-on-startup>1</load-on-startup></servlet><servlet-mapping><servlet-name>loadonstartupservlet</servlet-name><url-pattern>/startup</url-pattern></servlet-mapping></web-app> |
5、在xu.crontab包下新建两个java文件（文件位置见最上的截图）【其他java文件不用理会】
loadcrontabservlet.java
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package xu.crontab; import java.io.fileinputstream;import java.io.ioexception;import java.io.inputstream;import java.util.enumeration;import java.util.properties; import javax.servlet.servletconfig;import javax.servlet.servletexception;import javax.servlet.http.httpservlet; import org.jcrontab.crontab;import org.jcrontab.log.log; public class loadcrontabservlet extends httpservlet { /** * */private static final long serialversionuid = 1l;private crontab cron = null; public void init(servletconfig config) throws servletexception {super.init(config); try {system.out.print("working?...");process();system.out.println("ok");} catch (exception e) {throw new servletexception(e);}} protected inputstream createpropertiesstream(string name) throws ioexception {return new fileinputstream(name);} public void process() { string propz = "jcrontab.properties"; string props = getservletconfig().getinitparameter("properties_file");if (props == null) {props = propz;} properties propobj = new properties();try {inputstream input = createpropertiesstream(props);propobj.load(input);} catch (ioexception ioe) {ioe.printstacktrace();}servletconfig c = getservletconfig();enumeration keys = c.getinitparameternames();while (keys.hasmoreelements()) {string key = (string) keys.nextelement();propobj.setproperty(key, c.getinitparameter(key));} cron = crontab.getinstance(); try {shutdownhook();cron.init(propobj);} catch (exception e) {log.error(e.tostring(), e);}} public void shutdownhook() throws exception {runtime.getruntime().addshutdownhook(new thread() {public void run() {dostop();}});} public void destroy() {dostop();} public void dostop() {log.info("shutting down...");cron.uninit(100);log.info("stoped");}} |
crontab1.java
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package xu.crontab; import java.util.date; public class crontab1 { public static void run(string[] args) { system.out.println(new date()+"-----> hello world!!!"); }} |
启动tomcat后即可看到作业每隔5秒就调用一下，希望你们顺利。
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：http://blog.csdn.net/u013521220/article/details/78794134
