Spring MVC运行Cron作业

Question

How can i run cron job in spring webmvc framework with hibernate..?

Currently I have a application with spring-mvc and hibernate.i need to update the db every day night by calculating data from other tables in database.I have tried by write a java class with main method and run it with linux crontab.but in main method the sessionfactory gives a null instance.i need to done this with in the spring application because all my pojo's and methods are defined in that.i need to use it to calculation.

Answer 1

You can use @Scheduled annotation, here is an example :

To enable the @Scheduled annotation in java style

@Configuration
@EnableScheduling
public class SpringConfig {
   ...
}

Then annotate the desired method with @Scheduled like this using Cron expresion

@Scheduled(cron = "0 15 10 15 * ?")
public void scheduleTaskUsingCronExpression() {

    long now = System.currentTimeMillis() / 1000;
    System.out.println(
    "schedule tasks using cron jobs - " + now);
}

http://www.baeldung.com/spring-scheduled-tasks

Answer 2

Enable scheduling on your application :

@EnableScheduling
public class App {
}

And use @Scheduled annotation on desired method :

@Component
public class MyScheduler {

    @Scheduled(cron = "0 * * * * *")
    public void myJob() {
    }
}

Answer 3

You can implement ContextListener in your application. The listener will automatically call at the time of deployment.

You can below in your web.xml:

<listener>
    <listener-class>com.listener.CustomListener</listener-class>
</listener>

Create a class named CustomListener.

public class CustomListener extends ContextLoaderListener {

@Override
public void contextInitialized(ServletContextEvent event) {

    if (this.contextLoader == null) {
        this.contextLoader = this;
    }

    this.contextLoader.initWebApplicationContext(event.getServletContext());



}
   @Override
   public void contextDestroyed(ServletContextEvent event){
 }
}

ContextInitialized() will get call at time of deployment and contextDestroyed() will get call at undeployment.

You can add your scheduling code inside ContextInitialized() method.

You can use Spring + Quartz for scheduling or Java's Timer class

Timer class implementation will be easy to implement and debug.

Answer 4

• For spring-boot example:
  • Annotate your SpringBoot initialzer class with @EnableScheduling to enable scheduling: @SpringBootApplication @EnableScheduling public class HealthVendingMachineApplication { ... }
  • Create a method annotated with @Scheduled to perform a scheduling task: @Scheduled(fixedRate = 2000)//Or Use @Scheduled(cron='* * * *') public void scheduleTaskWithFixedRate() { ... System.out.println("King in the north... "); } @Scheduled(fixedRate = 2000)//Or Use @Scheduled(cron='* * * *') public void scheduleTaskWithFixedRate() { ... System.out.println("King in the north... "); }

ref-link

• For Spring-Mvc :

  • Create a configuration class to enable scheduling: @Configuration @EnableScheduling public class SpringConfig { ... }

  • Create a component class with methods performing scheduling operations: @Component public class MyScheduler { ... @Scheduled(cron = "0 * * * * *") public void myJob() { System.out.println("King in the north... "); } } @Component public class MyScheduler { ... @Scheduled(cron = "0 * * * * *") public void myJob() { System.out.println("King in the north... "); } }

  • You can use different fields provided by @Scheduled annotation. For eg, to schedule job at exactly x=2 seconds use @Scheduled(fixedRate = 2000) .

Edit : I am a beginner in Spring Web Apps development and even though I have tested these examples, kindly correct me if you find anything wrong with this comment.