Springboot中怎么利用@Scheduled實現定時任務

本篇文章為大家展示了Springboot中怎么利用@Scheduled實現定時任務，內容簡明扼要并且容易理解，絕對能使你眼前一亮，通過這篇文章的詳細介紹希望你能有所收獲。

使用@Scheduled 可以很容易實現定時任務

spring boot的版本 2.1.6.RELEASE

package com.abc.demo.common;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.scheduling.annotation.EnableScheduling;import org.springframework.scheduling.annotation.Scheduled;import org.springframework.stereotype.Component;import java.text.SimpleDateFormat;import java.util.concurrent.TimeUnit;@EnableScheduling@Componentpublic class ScheduleSetting {  private final Logger logger = LoggerFactory.getLogger(Tasks.class);  @Scheduled(fixedRate = 10000, initialDelay = 2000)  public void scheduleRead() {    try {      long timeStamp = System.currentTimeMillis();      SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");      Thread thread = Thread.currentThread();      System.out.println("cron1任務開始,start=" + simpleDateFormat.format(timeStamp) + ", threadId=" + thread.getId() + ", threadName=" + thread.getName());      long endStamp = System.currentTimeMillis();      try {        TimeUnit.SECONDS.sleep(20);      } catch (InterruptedException e) {        e.printStackTrace();      }      System.out.println("cron1任務正在運行的線程名稱：" + thread.getName() + " 結束,start=" + simpleDateFormat.format(timeStamp) + ",end=" + simpleDateFormat.format(endStamp));      System.out.println("++++++++++++++++++++++++");    } catch (Exception e) {      logger.error(e.getMessage());    }  }  @Scheduled(fixedRate = 5000, initialDelay = 1000)  public void scheduleConvert() {    try {      long timeStamp = System.currentTimeMillis();      SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");      Thread thread = Thread.currentThread();      System.out.println("cron2任務開始,start=" + simpleDateFormat.format(timeStamp) + ", threadId=" + thread.getId() + ", threadName=" + thread.getName());      try {        TimeUnit.SECONDS.sleep(10);      } catch (InterruptedException e) {        e.printStackTrace();      }      long endStamp = System.currentTimeMillis();      System.out.println("cron2任務正在運行的線程名稱：" + thread.getName() + " 結束,start=" + simpleDateFormat.format(timeStamp) + ",end=" + simpleDateFormat.format(endStamp));      System.out.println("====================");    } catch (Exception e) {      logger.error(e.getMessage());    }  }}

運行輸出內容為

cron2任務開始,start=2019-10-11 17:31:52, threadId=34, threadName=scheduling-1cron2任務正在運行的線程名稱：scheduling-1 結束,start=2019-10-11 17:31:52,end=2019-10-11 17:32:02====================cron1任務開始,start=2019-10-11 17:32:02, threadId=34, threadName=scheduling-1cron1任務正在運行的線程名稱：scheduling-1 結束,start=2019-10-11 17:32:02,end=2019-10-11 17:32:02++++++++++++++++++++++++cron2任務開始,start=2019-10-11 17:32:22, threadId=34, threadName=scheduling-1cron2任務正在運行的線程名稱：scheduling-1 結束,start=2019-10-11 17:32:22,end=2019-10-11 17:32:32……

注：

　　cron2執行完后才會執行cron1

原因：

　　spring默認是以單線程執行任務調度

　　spring的定時任務默認最大運行線程數為1，多個任務執行起來時間會有問題

1.配置線程池

在配置文件application.properties中添加

# 線程池大小spring.task.scheduling.pool.size=5# 線程名前綴spring.task.scheduling.thread-name-prefix=myScheduling-

輸出內容變為

cron2任務開始,start=2019-10-11 17:34:48, threadId=34, threadName=myScheduling-1cron1任務開始,start=2019-10-11 17:34:49, threadId=35, threadName=myScheduling-2cron2任務正在運行的線程名稱：myScheduling-1 結束,start=2019-10-11 17:34:48,end=2019-10-11 17:34:58====================cron2任務開始,start=2019-10-11 17:34:58, threadId=34, threadName=myScheduling-1cron2任務正在運行的線程名稱：myScheduling-1 結束,start=2019-10-11 17:34:58,end=2019-10-11 17:35:08====================cron2任務開始,start=2019-10-11 17:35:08, threadId=57, threadName=myScheduling-3cron1任務正在運行的線程名稱：myScheduling-2 結束,start=2019-10-11 17:34:49,end=2019-10-11 17:34:49……

注：

多線程下，cron1和cron2不用互相等待了，但是同一個任務還是需要等待的

2.并發

修改代碼

package com.abc.demo.common;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.scheduling.annotation.Async;import org.springframework.scheduling.annotation.EnableAsync;import org.springframework.scheduling.annotation.EnableScheduling;import org.springframework.scheduling.annotation.Scheduled;import org.springframework.stereotype.Component;import java.text.SimpleDateFormat;import java.util.concurrent.TimeUnit;@EnableScheduling@Component@EnableAsyncpublic class ScheduleSetting {  private final Logger logger = LoggerFactory.getLogger(Tasks.class);  @Async  @Scheduled(fixedRate = 10000, initialDelay = 2000)  public void scheduleRead() {    try {      long timeStamp = System.currentTimeMillis();      SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");      Thread thread = Thread.currentThread();      System.out.println("cron1任務開始,start=" + simpleDateFormat.format(timeStamp) + ", threadId=" + thread.getId() + ", threadName=" + thread.getName());      long endStamp = System.currentTimeMillis();      try {        TimeUnit.SECONDS.sleep(20);      } catch (InterruptedException e) {        e.printStackTrace();      }      System.out.println("cron1任務正在運行的線程名稱：" + thread.getName() + " 結束,start=" + simpleDateFormat.format(timeStamp) + ",end=" + simpleDateFormat.format(endStamp));      System.out.println("++++++++++++++++++++++++");    } catch (Exception e) {      logger.error(e.getMessage());    }  }  @Async  @Scheduled(fixedRate = 5000, initialDelay = 1000)  public void scheduleConvert() {    try {      long timeStamp = System.currentTimeMillis();      SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");      Thread thread = Thread.currentThread();      System.out.println("cron2任務開始,start=" + simpleDateFormat.format(timeStamp) + ", threadId=" + thread.getId() + ", threadName=" + thread.getName());      try {        TimeUnit.SECONDS.sleep(10);      } catch (InterruptedException e) {        e.printStackTrace();      }      long endStamp = System.currentTimeMillis();      System.out.println("cron2任務正在運行的線程名稱：" + thread.getName() + " 結束,start=" + simpleDateFormat.format(timeStamp) + ",end=" + simpleDateFormat.format(endStamp));      System.out.println("====================");    } catch (Exception e) {      logger.error(e.getMessage());    }  }}

輸出的內容

cron2任務開始,start=2019-10-11 17:39:53, threadId=57, threadName=task-1cron1任務開始,start=2019-10-11 17:39:54, threadId=59, threadName=task-2cron2任務開始,start=2019-10-11 17:39:58, threadId=61, threadName=task-3cron2任務開始,start=2019-10-11 17:40:03, threadId=63, threadName=task-4cron2任務正在運行的線程名稱：task-1 結束,start=2019-10-11 17:39:53,end=2019-10-11 17:40:03====================cron1任務開始,start=2019-10-11 17:40:04, threadId=64, threadName=task-5cron2任務開始,start=2019-10-11 17:40:08, threadId=65, threadName=task-6cron2任務正在運行的線程名稱：task-3 結束,start=2019-10-11 17:39:58,end=2019-10-11 17:40:08====================cron2任務開始,start=2019-10-11 17:40:13, threadId=66, threadName=task-7cron2任務正在運行的線程名稱：task-4 結束,start=2019-10-11 17:40:03,end=2019-10-11 17:40:13====================cron1任務正在運行的線程名稱：task-2 結束,start=2019-10-11 17:39:54,end=2019-10-11 17:39:54

說明：　

　　@EnableAsync開啟多線程  　　@Async標記其為一個異步任務  　　每個定時任務都是在通過不同的線程來處理，線程名的前綴成了task-  　　線程默認為10個

修改配置

spring.task.execution.thread-name-prefix=mytask-spring.task.execution.pool.core-size=5

重新運行的輸出

cron2任務開始,start=2019-10-11 17:44:00, threadId=56, threadName=mytask-1cron1任務開始,start=2019-10-11 17:44:01, threadId=57, threadName=mytask-2cron2任務開始,start=2019-10-11 17:44:05, threadId=58, threadName=mytask-3cron2任務開始,start=2019-10-11 17:44:10, threadId=59, threadName=mytask-4cron2任務正在運行的線程名稱：mytask-1 結束,start=2019-10-11 17:44:00,end=2019-10-11 17:44:10====================cron1任務開始,start=2019-10-11 17:44:11, threadId=60, threadName=mytask-5cron2任務正在運行的線程名稱：mytask-3 結束,start=2019-10-11 17:44:05,end=2019-10-11 17:44:15====================cron2任務開始,start=2019-10-11 17:44:15, threadId=58, threadName=mytask-3cron2任務開始,start=2019-10-11 17:44:20, threadId=56, threadName=mytask-1cron2任務正在運行的線程名稱：mytask-4 結束,start=2019-10-11 17:44:10,end=2019-10-11 17:44:20====================cron1任務正在運行的線程名稱：mytask-2 結束,start=2019-10-11 17:44:01,end=2019-10-11 17:44:01

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