Spring MVC Job Scheduling

Create a Spring MVC project 

Open spring tool suite
File > New > Spring Project > Spring Mvc Project

Test whether the project is working, if it's ok you should see a hello page in your browser.

Adding Dependency

Add following to pom.xml.

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${springframework.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${springframework.version}</version>
        </dependency>

 Create the scheduler

This is the class you want to schedule. Name it as ScheduledTasks.java and place with homecontroller.java

import java.text.SimpleDateFormat;
import java.util.Date;

import org.springframework.scheduling.annotation.Scheduled;


public class ScheduledTasks {

    SimpleDateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");
   
    @Scheduled(fixedRate=5000)
    public void reportCurrentTime(){
        System.out.println("time is : "+dateFormat.format(new Date()));
    }
   
}

 reportCurrentTime() methos will be called by Spring Scheduler every 5 seconds as the value set is 5000.

Configurations

This sample will use annotation based approach, so we shall create a AppConfig.java class for configurations.

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableScheduling;

@Configuration
@EnableScheduling
public class AppConfig {

    @Bean
    public ScheduledTasks bean(){
        return new ScheduledTasks();
    }
}

This @EnableScheduling annotation will ensure all the methods with @scheduled to add to scheduler.

Execution

Once your run the web application check the console output. You will notice time is been logged every 5 seconds.

Further

We can improve our application and change the pool size.  Let's change the pool size to 10. Change is made to AppConfig.java

import java.util.concurrent.Executor;
import java.util.concurrent.Executors;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.SchedulingConfigurer;
import org.springframework.scheduling.config.ScheduledTaskRegistrar;

@Configuration
@EnableScheduling
public class AppConfig implements SchedulingConfigurer {

    @Bean
    public ScheduledTasks bean(){
        return new ScheduledTasks();
    }

    @Override
    public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
        taskRegistrar.setScheduler(taskExecuter());
    }

    @Bean(destroyMethod="shutdown")
    public Executor taskExecuter() {
       
        return Executors.newScheduledThreadPool(10);
    }
}