spring-boot-starter-quartz组件的使用

目录

• spring-boot-starter-quartz组件的使用
• 前言
• 一、添加pom.xml依赖
• 二、application.properties添加数据库信息
• 三、数据库操作
• • 1.创建数据库test和表cron
  • 2.创建cron表对应的实体类
  • 3.创建Mapper
  • 4.创建Service
• 二、Quartz相关
• • 1.创建JobConfig类
  • 2.创建Job类
• 总结

---

前言

在做定时任务时，有需求是把定时执行cron表达式存在数据库中，通过更改数据库中的值，来改变任务执行的频率。

---

一、添加pom.xml依赖

<!--定时器依赖-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-quartz</artifactId>
</dependency>

<!--mybatis插件-->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>1.3.2</version>
</dependency>

<!--数据库连接插件-->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.13</version>
    <scope>runtime</scope>
</dependency>

二、application.properties添加数据库信息

spring.datasource.url:jdbc:mysql://localhost:3306/test?setUnicode=true&characterEncoding=utf8&serverTimezone=GMT%2B8&useSSL=false
spring.datasource.username:root
spring.datasource.password:root

三、数据库操作

1.创建数据库test和表cron

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
-- Table structure for cron
-- ----------------------------
DROP TABLE IF EXISTS `cron`;
CREATE TABLE `cron`  (
  `id` int NOT NULL AUTO_INCREMENT,
  `cron` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

-- ----------------------------
-- Records of cron
-- ----------------------------
INSERT INTO `cron` VALUES (1, '0/5 * * * * ? *');

cron表：

2.创建cron表对应的实体类

public class CronModel {
    private String cron;

    public String getCron() {
        return cron;
    }

    public void setCron(String cron) {
        this.cron = cron;
    }
}

3.创建Mapper

@Mapper
public interface CronModelMapper {
    @Select("select cron from cron where id = 1")
    String getCron();
}

4.创建Service

@Service
public class CronModelService {
    @Autowired
    CronModelMapper cronModelMapper;

    public String getCron() {
        return cronModelMapper.getCron();
    }

}

二、Quartz相关

1.创建JobConfig类

/**
 * Quartz的相关配置，注册JobDetail和Trigger
 * 注意JobDetail和Trigger是org.quartz包下的，不是spring包下的，不要导入错误
 */
@Configuration
public class JobConfig {

    @Autowired
    CronModelService cronModelService;

    @Bean
    public JobDetail jobDetail() {
        JobDetail jobDetail = JobBuilder.newJob(Job.class)
                .withIdentity("jobDetail", "jobDetail")
                .storeDurably()
                .build();
        return jobDetail;
    }

    @Bean
    public Trigger trigger() {
        Trigger trigger = TriggerBuilder.newTrigger()
                .forJob(jobDetail())
                .withIdentity("trigger", "trigger")
                .startNow()
                // 每天0点执行
                .withSchedule(CronScheduleBuilder.cronSchedule(cronModelService.getCron()))
                .build();
        return trigger;
    }
}

2.创建Job类

@Component
public class Job extends QuartzJobBean {

    Logger logger = LoggerFactory.getLogger(Job.class);

    @Autowired
    CronModelService cronModelService;

    @Autowired
    private Scheduler scheduler;

    @Override
    protected void executeInternal(JobExecutionContext jobExecutionContext) {
        logger.info("执行");
        Trigger trigger = jobExecutionContext.getTrigger();
        String cron = cronModelService.getCron();

        try {
            CronTrigger cronTrigger = (CronTrigger)
                    scheduler.getTrigger(trigger.getKey());
            String cronExpression = cronTrigger.getCronExpression();
            if (!cron.equals(cronExpression)) {
                //创建表达式调度器
                CronScheduleBuilder cronSchedule =
                        CronScheduleBuilder.cronSchedule(cron);
                //重构
                cronTrigger = cronTrigger.getTriggerBuilder()
                        .withIdentity(trigger.getKey())
                        .withSchedule(cronSchedule)
                        .build();
                scheduler.rescheduleJob(trigger.getKey(), cronTrigger);
            }
        } catch (SchedulerException e) {
            e.printStackTrace();
        }

    }
}

总结

和之前引入quartz包(参考Quartz文档)不同之处在于，之前是要先定义好Job和Trigger，然后通过Scheduler去绑定他们，最后去执行start来开启定时任务。而spring-boot-starter-quartz则省去了Job和Trigger的手动绑定（参考链接: SpringBoot官方文档），也就是做好2.1配置即可。