1. Get to know Quartz

1.1 overview

• Quartz is an open source task scheduling framework written entirely in Java. It is simple to say that developers can schedule tasks according to time intervals through quartz, for example:
  • Command the program to perform a task every hour
    
  • Command the program to perform one task every month
  • Specify the end of a month to command the program to perform a task
  • ......
• Quartz download address: http://www.quartz-scheduler.org/downloads/

1.2,Quartz API

1.2.1 scheduler -- the main API for interaction with the scheduler;

The life cycle of the Scheduler starts when the SchedulerFactory creates it and ends when the Scheduler calls the showdown() method. The Scheduler will actually Trigger trigger (execute job) only after scheduling the start() method. After the Scheduler is created, you can add, delete, list jobs and triggers, and perform other scheduling related operations.

1.2.2 Job -- interface to be implemented for tasks executed by scheduler

1.2.3 Job detail -- define the instance of Job

1.2.4 Trigger - Trigger the execution of Job

1.2.5 JobBuilder -- define the interface for creating JobDetail instance

1.2.6 Trigger builder -- define the interface for creating Trigger instance

2. Simple application of Hello Quartz

2.1. First, implement a simple small demo "Hello quartz!". Specific requirements: output a sentence "Hello quartz!" through the console every 5 seconds;

2.2, code

 1 package com.xxw.test;
 2 
 3 import org.quartz.Job;
 4 import org.quartz.JobExecutionContext;
 5 import org.quartz.JobExecutionException;
 6 
 7 public class MyJob implements Job{
 8 
 9     @Override
10     public void execute(JobExecutionContext arg0) throws JobExecutionException {
11         System.out.println("hello quartz!");
12     }
13     
14 }

 1 package com.xxw.test;
 2 
 3 import static org.quartz.JobBuilder.newJob;
 4 import static org.quartz.SimpleScheduleBuilder.simpleSchedule;
 5 import static org.quartz.TriggerBuilder.newTrigger;
 6 
 7 import org.quartz.JobDetail;
 8 import org.quartz.Scheduler;
 9 import org.quartz.Trigger;
10 import org.quartz.impl.StdSchedulerFactory;
11 
12 public class HellowQuartz {
13 
14     public static void main(String[] args) {
15         try {
16             // Definition JobDetail
17             JobDetail job = newJob(MyJob.class) // Definition Job Class is MyJob Class, which is the task logic class
18                     .withIdentity("job1", "group1") // Definition name/group
19                     .build();
20             
21             // Define a Trigger
22             Trigger trigger = newTrigger()
23                     .withIdentity("trigger1", "group1") // Definition name/group
24                     .startNow() // Once joined scheduler，Effective immediately
25                     .withSchedule(
26                             simpleSchedule() // Use simpleSchedule
27                             .withIntervalInSeconds(5) // Every 5 seconds
28                             .repeatForever()) // Always execute
29                     .build();
30             
31             // Example Schedule Scheduler
32             Scheduler scheduler = StdSchedulerFactory.getDefaultScheduler();
33             // Add scheduling
34             scheduler.scheduleJob(job, trigger);
35             // start-up
36             scheduler.start();
37             
38         } catch (Exception e) {
39             e.printStackTrace();
40         }
41     }
42 }

2.3, result