Quartz explanation and use

Catalog

1.Quartz Introduce

2. Quartz The trigger of

2.1 Five types of Trigger( Timer )

3. storage

3.2 cron expression

 4.Quartz Create a scheduled task

4.1 Import Quartz rely on

4.2job The task class  

4.3 Specific business implementation

5 Quartz Detailed explanation of core classes

5.1 Scheduler Scheduler

5.2 Job Timing task

5.3 Trigger trigger

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1.Quartz Introduce

Task scheduling framework “Quartz” yes OpenSymphony Open source organizations in Job scheduling Another open source project in the field , It's all about java Developed an open source task schedule management system ,“ Task progress Manager ” It's a pre-determined （ Be put on the agenda ） When the time arrives , Responsible for the execution of （ Or notice ） Other software components of the system .

To put it simply, to realize “ plan ( Or timing ) Mission ” The system of , for example ： No payment after order placed ,15 Automatically cancel the order in minutes , And automatically unlock the locked goods

2. Quartz The trigger of

Triggers are used to tell the scheduler when a job is triggered . The framework provides 5 Trigger types , But the two most commonly used SimpleTrigger and CronTrigger.

2.1 Five types of Trigger( Timer )

SimpleTrigger,CronTirgger,DateIntervalTrigger,NthIncludedDayTrigger and Calendar class （ org.quartz.Calendar）.

scene ：

SimpleTrigger： perform N Time , repeat N Time

CronTrigger： Seconds A little bit When? What day Which month Which week Which year , perform

3. storage

 RAMJobStore( Memory job storage type ) and JDBCJobStore( Database job storage type ), The two methods are compared as follows ：

   3.1 RAMJobStore  Don't external databases , Easy to configure , Fast running speed     Because the scheduler information is stored in the assigned to JVM In the memory of ,  therefore , When the application stops running , All scheduling information will be lost . And because of the storage in JVM In memory , So how many can be stored Job and Trigger There will be restrictions

   3.2 JDBCJobStore  Support clusters , Because all the task information will be saved     The speed of running depends on the speed of connecting to the database , Can control things , And if the application server is shut down or restarted , Mission information will not be lost , And you can recover tasks that failed to execute due to server shutdown or restart    

3.2 cron expression

 4.Quartz Create a scheduled task

4.1 Import Quartz rely on

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-quartz</artifactId>
        </dependency>

4.2job The task class  

package com.wyy.quartz.Text;

import lombok.extern.log4j.Log4j2;
import lombok.extern.slf4j.Slf4j;
import org.quartz.Job;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;

@Component
@Slf4j
public class MyJob implements Job {


    @Override
    public void execute(JobExecutionContext Context) throws JobExecutionException {
        Object name = Context.getJobDetail().getJobDataMap().get("name");
        log.warn(name+" Doing hygiene ");
    }
}

4.3 Specific business implementation

package com.wyy.quartz.Text;

import org.quartz.*;
import org.quartz.impl.StdSchedulerFactory;
import org.springframework.stereotype.Component;

import java.util.Date;

import static org.quartz.JobBuilder.newJob;

@Component
public class scheduler {

    public void getScheduler() {
        // Create a dispatch factory class instance StdSchedulerFactory
        StdSchedulerFactory stdSchedulerFactory = new StdSchedulerFactory();
        try {
            // Create a scheduler instance Scheduler
            Scheduler scheduler = stdSchedulerFactory.getScheduler();
            // Create task details JobDetail
            JobDetail jobDetail = newJob(MyJob.class)
                    .withIdentity("detail01", "group01")  // Define task PK   Make up a unique logo 
                    .withDescription("this is a jobDetail")// describe 
                    .usingJobData("name", " Zhang San ")// Method 1 of transferring values to the specific operation class 
                    .build();// Build tasks 
            // The second method is to transfer values to the specific operation class 
//            JobDataMap jobDataMap = jobDetail.getJobDataMap();
//            jobDataMap.put("name", " Zhang San ");
            // Create trigger 
            Trigger trigger = (Trigger) TriggerBuilder.newTrigger()
                    .withIdentity("trigger1", "group01")   // Make up a unique logo 
                    .startAt(new Date())             // Starting time 
                    .withDescription("this is a trigger")
                    // Simple trigger 
                    .withSchedule(SimpleScheduleBuilder.simpleSchedule()
                      // Repeat every two seconds 3 Time 
                      .withIntervalInSeconds(2).withRepeatCount(3))
                    // Expression scheduler （ Generate scheduled task expressions online ：http://cron.qqe2.com/）
                    // Every time 5 Execute the job class logic code every second 
                    //.withSchedule(CronScheduleBuilder.cronSchedule("0/5 * * * * ? "))
                    .build();
            // Inject job classes and triggers into the scheduler 
            scheduler.scheduleJob(jobDetail, trigger);
            // Start the scheduler 
            scheduler.start();

        } catch (SchedulerException e) {
            e.printStackTrace();
        }

    }
}

  The above business codes mainly involve  Scheduler Scheduler 、Job Timing task 、Trigger trigger Three categories （quartz Core class ）

5 Quartz Detailed explanation of core classes

5.1 Scheduler Scheduler

The main program interface used to interact with the scheduler . Scheduler One was maintained JobDetails and Triggers The registry .
Once in a Scheduler Registered , When the trigger time of the scheduled task arrives , The scheduler will be responsible for executing predefined Job After the scheduler is created , be in “ standby ” state , Must call scheduler Of start() Method to enable the scheduler
have access to shutdown() Method to close the scheduler , Use isShutdown() Method to determine whether the scheduler is closed . adopt Scheduler.scheduleJob(…) Method to include the task in the scheduler , When the task trigger time is up , The task will be performed .

5.2 Job Timing task

Generate task details through task classes （ A task class can have multiple task details ）, Pass parameters to the task class .

5.3 Trigger trigger

Trigger use TriggerBuilder To instantiate , There is one TriggerKey relation , In a Scheduler It has to be the only one . Multiple triggers can point to the same job , But a trigger can only point to one job . Triggers can transmit data to job, By putting data into the trigger JobDataMap.