Spring Boot任务调度问题：新增ProducerService未被调用

背景 #

按照Spring官方指南搭建的基础Spring Boot调度器，运行SchedulingTasksApplication时，ScheduledTasks类能按预期重复打印日志。

ScheduledTasks类 #

package com.climate.schedulingtasks;

import java.text.SimpleDateFormat;
import java.util.Date;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;

@Component
public class ScheduledTasks {

    private static final Logger log = LoggerFactory.getLogger(ScheduledTasks.class);

    private static final SimpleDateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");

    @Scheduled(fixedRate = 5000)
    public void reportCurrentTime() {
        log.info("当前时间: {}", dateFormat.format(new Date()));
    }
}

SchedulingTasksApplication类 #

package com.climate.schedulingtasks;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableScheduling;

@SpringBootApplication
@EnableScheduling
public class SchedulingTasksApplication {

    public static void main(String[] args) {
        SpringApplication.run(SchedulingTasksApplication.class);
    }
}

问题 #

新增ProducerService类用于生成5条消息，添加了相关注解，但运行时该服务从未被调用。

ProducerService类 #

package com.climate.eventplatform.client.jobs.heartbeat;

import com.climate.eventplatform.client.EventPlatformClientException;
import com.climate.schedulingtasks.ScheduledTasks;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;

import java.io.IOException;

@Component
public class ProducerService {

    private static final Logger log = LoggerFactory.getLogger(ScheduledTasks.class);

    @Scheduled(fixedRate = 5000)
    public static void main(String[] args) throws EventPlatformClientException, InterruptedException, IOException {
        HeartBeatProducer.produceAll("Producer 1");
        log.info("生产者运行中");
    }
}

解决方法 #

• 静态方法无法被Spring调度：@Scheduled注解仅支持非静态方法，Spring需要通过Bean实例调用调度逻辑。将main方法改为非静态方法：

  @Scheduled(fixedRate = 5000)
  public void produceHeartbeats() throws EventPlatformClientException, InterruptedException, IOException {
      HeartBeatProducer.produceAll("Producer 1");
      log.info("生产者运行中");
  }
  

• 包扫描范围不匹配：@SpringBootApplication默认仅扫描当前包及其子包，ProducerService所在的com.climate.eventplatform.client.jobs.heartbeat不在默认扫描范围内。可通过两种方式解决：

  1. 将ProducerService移至com.climate.schedulingtasks或其子包下；
  2. 修改SchedulingTasksApplication的注解，指定扫描包范围：

     @SpringBootApplication(scanBasePackages = {"com.climate.schedulingtasks", "com.climate.eventplatform.client.jobs.heartbeat"})
     @EnableScheduling
     public class SchedulingTasksApplication {
         // ...
     }
     

• 日志初始化错误：当前日志使用ScheduledTasks类初始化，建议改为自身类，便于日志排查：

  private static final Logger log = LoggerFactory.getLogger(ProducerService.class);
  

内容的提问来源于stack exchange，提问作者Hofbr