定时任务--单点系统

Posted 2020-12-01 yuhuiqing

 1 public class Demo01 {
 2     static long count = 0;
 3     public static void main(String[] args) {
 4         Runnable runnable = new Runnable() {
 5             @Override
 6             public void run() {
 7                 while (true) {
 8                     try {
 9                         Thread.sleep(1000);
10                         count++;
11                         System.out.println(count);
12                     } catch (Exception e) {
13                         // TODO: handle exception
14                     }
15                 }
16             }
17         };
18         Thread thread = new Thread(runnable);
19         thread.start();
20     }
21 }

Thread线程定时任务

 1 /**
 2  * 使用TimerTask类实现定时任务
 3 */
 4 public class Demo02 {
 5     static long count = 0;
 6 
 7     public static void main(String[] args) {
 8         TimerTask timerTask = new TimerTask() {
 9 
10             @Override
11             public void run() {
12                 count++;
13                 System.out.println(count);
14             }
15         };
16         Timer timer = new Timer();
17         // 天数
18         long delay = 0;
19         // 秒数
20         long period = 1000;
21         timer.scheduleAtFixedRate(timerTask, delay, period);
22     }
23 
24 }

TimerTask

 1 public class Demo003 {
 2     public static void main(String[] args) {
 3         Runnable runnable = new Runnable() {
 4             public void run() {
 5                 // task to run goes here
 6                 System.out.println("Hello !!");
 7             }
 8         };
 9         ScheduledExecutorService service = Executors.newSingleThreadScheduledExecutor();
10         // 第二个参数为首次执行的延时时间，第三个参数为定时执行的间隔时间
11         service.scheduleAtFixedRate(runnable, 1, 1, TimeUnit.SECONDS);
12     }
13 }

线程池定时ScheduledExecutorService

 Quartz定时任务

1、引入jar包

 1 <dependencies>
 2         <!-- quartz -->
 3         <dependency>
 4             <groupId>org.quartz-scheduler</groupId>
 5             <artifactId>quartz</artifactId>
 6             <version>2.2.1</version>
 7         </dependency>
 8         <dependency>
 9             <groupId>org.quartz-scheduler</groupId>
10             <artifactId>quartz-jobs</artifactId>
11             <version>2.2.1</version>
12         </dependency>
13     </dependencies>

Pom.xml

1 public class MyJob implements Job {
2     public void execute(JobExecutionContext context) throws JobExecutionException {
3         System.out.println("quartz MyJob date:" + new Date().getTime());
4     }
5 }

定时任务

 1  //1.创建Scheduler的工厂
 2       SchedulerFactory sf = new StdSchedulerFactory();
 3       //2.从工厂中获取调度器实例
 4       Scheduler scheduler = sf.getScheduler();
 5 
 6 
 7       //3.创建JobDetail
 8       JobDetail jb = JobBuilder.newJob(MyJob.class)
 9               .withDescription("this is a ram job") //job的描述
10               .withIdentity("ramJob", "ramGroup") //job 的name和group
11               .build();
12 
13       //任务运行的时间，SimpleSchedle类型触发器有效
14       long time=  System.currentTimeMillis() + 3*1000L; //3秒后启动任务
15       Date statTime = new Date(time);
16 
17       //4.创建Trigger
18           //使用SimpleScheduleBuilder或者CronScheduleBuilder
19       Trigger t = TriggerBuilder.newTrigger()
20                   .withDescription("")
21                   .withIdentity("ramTrigger", "ramTriggerGroup")
22                   //.withSchedule(SimpleScheduleBuilder.simpleSchedule())
23                   .startAt(statTime)  //默认当前时间启动
24                   .withSchedule(CronScheduleBuilder.cronSchedule("0/2 * * * * ?")) //两秒执行一次
25                   .build();
26 
27       //5.注册任务和定时器
28       scheduler.scheduleJob(jb, t);
29 
30       //6.启动 调度器
31       scheduler.start();

启动类调度

cron表达示：http://cron.qqe2.com/