basic concept
Definition: task scheduling open source framework
Task scheduling:
In enterprise-level applications, some "scheduled tasks" are often formulated, that is, to do something at a certain point in time.
- The core is time as the focus, that is, at a specific point in time, the system performs a specified operation.
- Task scheduling involves multi-thread concurrency, thread pool maintenance, run-time rule analysis, protection and recovery of the running site, etc.
The Quartz framework is an open source enterprise-level task scheduling service, which has been regarded as a good solution for task scheduling.
Quartz highly abstracts task scheduling, proposes three core concepts, and describes them through interfaces and classes in the org.quartz package
Task: It is the content of the work to be performed. Quartz provides Job interface to support task definition
Trigger: Define the time trigger rules that trigger Job execution. Quartz provides the Trigger class and its subclasses to support trigger functions
Scheduler: Quartz provides a Scheduler interface to bind work tasks and triggers to ensure that tasks can be executed at the correct time
Example:
1. Import coordinate dependencies:
<dependency>
<groupId>commons-collections</groupId>
<artifactId>commons-collections</artifactId>
<version>3.1</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-io</artifactId>
<version>1.3.2</version>
</dependency>
<dependency>
<groupId>commons-logging</groupId>
<artifactId>commons-logging</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>org.quartz-scheduler</groupId>
<artifactId>quartz</artifactId>
<version>1.8.3</version>
</dependency>
<dependency>
<groupId>org.quartz-scheduler</groupId>
<artifactId>quartz-jobs</artifactId>
<version>2.2.3</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.36</version>
</dependency>2. Create an implementation class that implements Job:
public class MyJob implements Job {
@Override
public void execute(JobExecutionContext jobExecutionContext) throws JobExecutionException {
System.out.println("TriggerName:"+jobExecutionContext.getTrigger().getName());
System.out.println("TriggerTime:"+new Date());
System.out.println("JobName:"+jobExecutionContext.getJobDetail().getName());
System.out.println("妈妈喊你回家吃饭");
}
}3. Specifically enable task scheduling:
//TODO:任务
try {
//1.定义任务对象
JobDetail job = new JobDetail("task1","miaoGroup", MyJob.class);
//2.创建SimpleTrigger触发器(间隔触发)
SimpleTrigger simpleTrigger = new SimpleTrigger("trigger1", "miaoTrigger",SimpleTrigger.REPEAT_INDEFINITELY,3000);
//2.创建CronTrigger触发器(特定触发)
CronTrigger cronTrigger = new CronTrigger("trigger1","miaoTrigger","0 58 10 ? * *");
//3.创建调度器
SchedulerFactory factory = new StdSchedulerFactory();
Scheduler scheduler = factory.getScheduler();
scheduler.scheduleJob(job,simpleTrigger);
//4.启动调度器
scheduler.start();
} catch (SchedulerException e) {
e.printStackTrace();
}SimpleTrigger: Define the interval time node trigger
CronTrigger: Define a specific time node trigger
Cron expression: consists of 6~7 time elements separated by spaces. The seventh element is optional.
| Location | field meaning | scope | special characters allowed |
| 1 | Second | 0~59 | *_/ |
| 2 | minute | 0~59 | *_/ |
| 3 | Hour | 0~23 | *_/ |
| 4 | day of the month | 1~31 | *_/?L |
| 5 | month | 1~12 or JAN~DEC | *_/ |
| 6 | Day of the week | 1~7 or SUN~SAT | * / ? L # |
| 7 | years | 1970~2099 | * / |
Each field in a Cron expression can explicitly specify a value (such as 49), a range (1-6), a list (1, 3, 5) or a wildcard (such as *)
Cron expressions have several special characters, which are described as follows:
"-": a dash, indicating a range
",": Use comma-separated data to represent a list
"*": means every value, it can be used for all fields. Example: Express hourly in the hour field
"?": This character is only used in the "day of month" field and "day of week" field, indicating that no value is specified
"/": usually expressed as x/y, x is the starting value, and y represents the growth of the value
"L": Indicates the last day, used only in date and week fields
"#": It can only be used in the "day of the week" field, indicating the first few days of the month. Example: "6#3" refers to the third Friday of the month
exclude time rule
It can be implemented using the Calendar interface provided by Quartz, and Quartz provides a variety of implementation classes to meet the needs of the application
| Calendar name | effect |
| WeeklyCalendar | Used to exclude one or more days of the week |
| MonthlyCalendar | Used to exclude days of the month |
| AnnualCalendar | Used to exclude one or more days of the year |
| HolidayCalendar | Used to exclude holidays |
Note: The Calendar interface is provided by quartz, not the calendar class under the java.util package in jdk
Example: exclude the first day of every Monday
//TODO:任务
try {
//1.定义任务对象
JobDetail job = new JobDetail("task1","miaoGroup", MyJob.class);
//2.创建SimpleTrigger触发器(间隔触发)
// SimpleTrigger simpleTrigger = new SimpleTrigger("trigger1", "miaoTrigger",SimpleTrigger.REPEAT_INDEFINITELY,3000);
//2.创建CronTrigger触发器(特定触发)
CronTrigger cronTrigger = new CronTrigger("trigger1","miaoTrigger","0 32 11 ? * * ");
//2.1排除
AnnualCalendar annualCalendar = new AnnualCalendar();
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.MONTH,1);
calendar.set(Calendar.DATE,1);
annualCalendar.setDayExcluded(calendar,true);
//3.创建调度器
SchedulerFactory factory = new StdSchedulerFactory();
Scheduler scheduler = factory.getScheduler();
scheduler.scheduleJob(job,cronTrigger);
scheduler.addCalendar("exclued",annualCalendar,true,true);
//4.启动调度器
scheduler.start();
} catch (Exception e) {
e.printStackTrace();
}