一 我們使用@EnableScheduling 開啟spring task 排程器的時候，發現此排程器預設配置為單執行緒的。

二 開啟註解發現其配置資訊在此SchedulingConfiguration類中。發現其建立了ScheduledTaskRegistrar類
研讀程式碼不難發現排程器預設配置是如下程式碼，執行緒池為單執行緒的。

protected void scheduleTasks() {
 if (this.taskScheduler == null) {
  this.localExecutor = Executors.newSingleThreadScheduledExecutor();
  this.taskScheduler = new ConcurrentTaskScheduler(this.localExecutor);
 }
 if (this.triggerTasks != null) {
  for (TriggerTask task : this.triggerTasks) {
  addScheduledTask(scheduleTriggerTask(task));
  }
 }
 if (this.cronTasks != null) {
  for (CronTask task : this.cronTasks) {
  addScheduledTask(scheduleCronTask(task));
  }
 }
 if (this.fixedRateTasks != null) {
  for (IntervalTask task : this.fixedRateTasks) {
  addScheduledTask(scheduleFixedRateTask(task));
  }
 }
 if (this.fixedDelayTasks != null) {
  for (IntervalTask task : this.fixedDelayTasks) {
  addScheduledTask(scheduleFixedDelayTask(task));
  }
 }
 }

如何改變此配置呢？

如果想改變其中配置則只需要如下核心程式碼

package com.ccbobe.common.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.SchedulingConfigurer;
import org.springframework.scheduling.config.ScheduledTaskRegistrar;

import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledThreadPoolExecutor;

@EnableScheduling
@Configuration
public class SchedulerConfig implements SchedulingConfigurer {
  @Bean
  public ScheduledExecutorService concurrentTaskScheduler(){
    ScheduledThreadPoolExecutor executorService = new ScheduledThreadPoolExecutor(20);
    executorService.setMaximumPoolSize(20);
    executorService.setRejectedExecutionHandler(new ScheduledThreadPoolExecutor.CallerRunsPolicy());
    return executorService;
  }
  @Override
  public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
    taskRegistrar.setScheduler(concurrentTaskScheduler());
  }
}

其中Scheduler 支援兩種，種分別是：TaskScheduler 和 ScheduledExecutorService

/**
 * Set the {@link TaskScheduler} to register scheduled tasks with,or a
 * {@link java.util.concurrent.ScheduledExecutorService} to be wrapped as a
 * {@code TaskScheduler}.
 */
 public void setScheduler(@Nullable Object scheduler) {
 if (scheduler == null) {
  this.taskScheduler = null;
 }
 else if (scheduler instanceof TaskScheduler) {
  this.taskScheduler = (TaskScheduler) scheduler;
 }
 else if (scheduler instanceof ScheduledExecutorService) {
  this.taskScheduler = new ConcurrentTaskScheduler(((ScheduledExecutorService) scheduler));
 }
 else {
  throw new IllegalArgumentException("Unsupported scheduler type: " + scheduler.getClass());
 }
 }

完成以上配置，即可讓spring task 執行在多執行緒環境中。

以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支援我們。