如何在springboot中利用Quartz实现一个定时任务功能

<dependency> 
      <groupId>org.springframework.boot</groupId> 
      <artifactId>spring-boot-starter-data-jpa</artifactId> 
    </dependency> 
 
    <dependency><!-- 为了方便测试，此处使用了内存数据库 --> 
      <groupId>com.h3database</groupId> 
      <artifactId>h3</artifactId> 
      <scope>runtime</scope> 
    </dependency> 
    <dependency> 
      <groupId>org.springframework.boot</groupId> 
      <artifactId>spring-boot-starter-test</artifactId> 
      <scope>test</scope> 
    </dependency> 
     
    <dependency> 
      <groupId>org.quartz-scheduler</groupId> 
      <artifactId>quartz</artifactId> 
      <version>2.2.1</version> 
      <exclusions> 
        <exclusion> 
          <artifactId>slf4j-api</artifactId> 
          <groupId>org.slf4j</groupId> 
        </exclusion> 
      </exclusions> 
    </dependency> 
    <dependency><!-- 该依赖必加，里面有sping对schedule的支持 --> 
            <groupId>org.springframework</groupId> 
            <artifactId>spring-context-support</artifactId> 
    </dependency> 

# 服务器端口号  
server.port=7902 
# 是否生成ddl语句  
spring.jpa.generate-ddl=false  
# 是否打印sql语句  
spring.jpa.show-sql=true  
# 自动生成ddl，由于指定了具体的ddl，此处设置为none  
spring.jpa.hibernate.ddl-auto=none  
# 使用H2数据库  
spring.datasource.platform=h3  
# 指定生成数据库的schema文件位置  
spring.datasource.schema=classpath:schema.sql  
# 指定插入数据库语句的脚本位置  
spring.datasource.data=classpath:data.sql  
# 配置日志打印信息  
logging.level.root=INFO  
logging.level.org.hibernate=INFO  
logging.level.org.hibernate.type.descriptor.sql.BasicBinder=TRACE  
logging.level.org.hibernate.type.descriptor.sql.BasicExtractor=TRACE  
logging.level.com.itmuch=DEBUG  

package com.chhliu.springboot.quartz.entity; 
 
import javax.persistence.Column; 
import javax.persistence.Entity; 
import javax.persistence.GeneratedValue; 
import javax.persistence.GenerationType; 
import javax.persistence.Id; 
 
@Entity 
public class Config { 
  @Id 
   @GeneratedValue(strategy = GenerationType.AUTO) 
   private Long id; 
 
   @Column 
   private String cron; 
 
  /** 
   * @return the id 
   */ 
  public Long getId() { 
    return id; 
  } 
    ……此处省略getter和setter方法…… 
} 

package com.chhliu.springboot.quartz.entity; 
 
import org.slf4j.Logger; 
import org.slf4j.LoggerFactory; 
import org.springframework.context.annotation.Configuration; 
import org.springframework.scheduling.annotation.EnableScheduling; 
import org.springframework.stereotype.Component; 
 
@Configuration 
@Component // 此注解必加 
@EnableScheduling // 此注解必加 
public class ScheduleTask { 
  private static final Logger LOGGER = LoggerFactory.getLogger(ScheduleTask.class); 
  public void sayHello(){ 
    LOGGER.info("Hello world, i'm the king of the world!!!"); 
  } 
} 

package com.chhliu.springboot.quartz.entity; 
 
import org.quartz.Trigger; 
import org.springframework.context.annotation.Bean; 
import org.springframework.context.annotation.Configuration; 
import org.springframework.scheduling.quartz.CronTriggerFactoryBean; 
import org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean; 
import org.springframework.scheduling.quartz.SchedulerFactoryBean; 
 
@Configuration 
public class QuartzConfigration { 
  /** 
   * attention: 
   * Details：配置定时任务 
   */ 
  @Bean(name = "jobDetail") 
  public MethodInvokingJobDetailFactoryBean detailFactoryBean(ScheduleTask task) {// ScheduleTask为需要执行的任务 
    MethodInvokingJobDetailFactoryBean jobDetail = new MethodInvokingJobDetailFactoryBean(); 
    /* 
     * 是否并发执行 
     * 例如每5s执行一次任务，但是当前任务还没有执行完，就已经过了5s了， 
     * 如果此处为true，则下一个任务会执行，如果此处为false，则下一个任务会等待上一个任务执行完后，再开始执行 
     */ 
    jobDetail.setConcurrent(false); 
     
    jobDetail.setName("srd-chhliu");// 设置任务的名字 
    jobDetail.setGroup("srd");// 设置任务的分组，这些属性都可以存储在数据库中，在多任务的时候使用 
     
    /* 
     * 为需要执行的实体类对应的对象 
     */ 
    jobDetail.setTargetObject(task); 
     
    /* 
     * sayHello为需要执行的方法 
     * 通过这几个配置，告诉JobDetailFactoryBean我们需要执行定时执行ScheduleTask类中的sayHello方法 
     */ 
    jobDetail.setTargetMethod("sayHello"); 
    return jobDetail; 
  } 
   
  /** 
   * attention: 
   * Details：配置定时任务的触发器，也就是什么时候触发执行定时任务 
   */ 
  @Bean(name = "jobTrigger") 
  public CronTriggerFactoryBean cronJobTrigger(MethodInvokingJobDetailFactoryBean jobDetail) { 
    CronTriggerFactoryBean tigger = new CronTriggerFactoryBean(); 
    tigger.setJobDetail(jobDetail.getObject()); 
    tigger.setCronExpression("0 30 20 * * ?");// 初始时的cron表达式 
    tigger.setName("srd-chhliu");// trigger的name 
    return tigger; 
 
  } 
 
  /** 
   * attention: 
   * Details：定义quartz调度工厂 
   */ 
  @Bean(name = "scheduler") 
  public SchedulerFactoryBean schedulerFactory(Trigger cronJobTrigger) { 
    SchedulerFactoryBean bean = new SchedulerFactoryBean(); 
    // 用于quartz集群,QuartzScheduler 启动时更新己存在的Job 
    bean.setOverwriteExistingJobs(true); 
    // 延时启动，应用启动1秒后 
    bean.setStartupDelay(1); 
    // 注册触发器 
    bean.setTriggers(cronJobTrigger); 
    return bean; 
  } 
} 

package com.chhliu.springboot.quartz.entity; 
 
import javax.annotation.Resource; 
 
import org.quartz.CronScheduleBuilder; 
import org.quartz.CronTrigger; 
import org.quartz.JobDetail; 
import org.quartz.Scheduler; 
import org.quartz.SchedulerException; 
import org.springframework.beans.factory.annotation.Autowired; 
import org.springframework.context.annotation.Configuration; 
import org.springframework.scheduling.annotation.EnableScheduling; 
import org.springframework.scheduling.annotation.Scheduled; 
import org.springframework.stereotype.Component; 
 
import com.chhliu.springboot.quartz.repository.ConfigRepository; 
 
@Configuration 
@EnableScheduling 
@Component 
public class ScheduleRefreshDatabase { 
  @Autowired 
  private ConfigRepository repository; 
 
  @Resource(name = "jobDetail") 
  private JobDetail jobDetail; 
 
  @Resource(name = "jobTrigger") 
  private CronTrigger cronTrigger; 
 
  @Resource(name = "scheduler") 
  private Scheduler scheduler; 
 
  @Scheduled(fixedRate = 5000) // 每隔5s查库，并根据查询结果决定是否重新设置定时任务 
  public void scheduleUpdateCronTrigger() throws SchedulerException { 
    CronTrigger trigger = (CronTrigger) scheduler.getTrigger(cronTrigger.getKey()); 
    String currentCron = trigger.getCronExpression();// 当前Trigger使用的 
    String searchCron = repository.findOne(1L).getCron();// 从数据库查询出来的 
    System.out.println(currentCron); 
    System.out.println(searchCron); 
    if (currentCron.equals(searchCron)) { 
      // 如果当前使用的cron表达式和从数据库中查询出来的cron表达式一致，则不刷新任务 
    } else { 
      // 表达式调度构建器 
      CronScheduleBuilder scheduleBuilder = CronScheduleBuilder.cronSchedule(searchCron); 
      // 按新的cronExpression表达式重新构建trigger 
      trigger = (CronTrigger) scheduler.getTrigger(cronTrigger.getKey()); 
      trigger = trigger.getTriggerBuilder().withIdentity(cronTrigger.getKey()) 
          .withSchedule(scheduleBuilder).build(); 
      // 按新的trigger重新设置job执行 
      scheduler.rescheduleJob(cronTrigger.getKey(), trigger); 
      currentCron = searchCron; 
    } 
  } 
} 

insert into config(id,cron) values(1,'0 0/2 * * * ?'); # 每2分钟执行一次定时任务

drop table config if exists; 
create table config( 
  id bigint generated by default as identity, 
  cron varchar(40), 
  primary key(id) 
); 

0 30 20 * * ? 
0 0/2 * * * ? 
2017-03-08 18:02:00.025 INFO 5328 --- [eduler_Worker-1] c.c.s.quartz.entity.ScheduleTask     : Hello world, i'm the king of the world!!! 
2017-03-08 18:04:00.003 INFO 5328 --- [eduler_Worker-2] c.c.s.quartz.entity.ScheduleTask     : Hello world, i'm the king of the world!!! 
2017-03-08 18:06:00.002 INFO 5328 --- [eduler_Worker-3] c.c.s.quartz.entity.ScheduleTask     : Hello world, i'm the king of the world!!! 
2017-03-08 18:08:00.002 INFO 5328 --- [eduler_Worker-4] c.c.s.quartz.entity.ScheduleTask     : Hello world, i'm the king of the world!!!