本节内容是通过定时任务定时检查租约是否到期。SpringBoot内置了定时任务，具体实现如下。

• 启用Spring Boot定时任务

在SpringBoot启动类上增加@EnableScheduling注解，如下

  @SpringBootApplication
  @EnableScheduling
  public class AdminWebApplication {
      public static void main(String[] args) {
          SpringApplication.run(AdminWebApplication.class, args);
      }
  }

• 编写定时逻辑

  在web-admin模块下创建com.atguigu.lease.web.admin.schedule.ScheduledTasks类，内容如下

  @Component
  public class ScheduledTasks {

      @Autowired
      private LeaseAgreementService leaseAgreementService;

      @Scheduled(cron = "0 0 0 * * *")
      public void checkLeaseStatus() {

          LambdaUpdateWrapper<LeaseAgreement> updateWrapper = new LambdaUpdateWrapper<>();
          Date now = new Date();
          updateWrapper.le(LeaseAgreement::getLeaseEndDate, now);
          updateWrapper.eq(LeaseAgreement::getStatus, LeaseStatus.SIGNED);
          updateWrapper.in(LeaseAgreement::getStatus, LeaseStatus.SIGNED, LeaseStatus.WITHDRAWING);

          leaseAgreementService.update(updateWrapper);
      }
  }

知识点:

SpringBoot中的cron表达式语法如下

    ┌───────────── second (0-59)
    │ ┌───────────── minute (0 - 59)
    │ │ ┌───────────── hour (0 - 23)
    │ │ │ ┌───────────── day of the month (1 - 31)
    │ │ │ │ ┌───────────── month (1 - 12) (or JAN-DEC)
    │ │ │ │ │ ┌───────────── day of the week (0 - 7)
    │ │ │ │ │ │          (0 or 7 is Sunday, or MON-SUN)
    │ │ │ │ │ │
    * * * * * *

六个星星就是每秒都在执行

package com.atguigu.lease.web.admin.schedule;

import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;

import java.util.Date;

@Component
public class ScheduleTasks {

    @Scheduled(cron = "* * * * * *")
    public void test(){
        System.out.println(new Date());
    }
}

三个星星是每天

package com.atguigu.lease.web.admin.schedule;

import com.atguigu.lease.model.entity.LeaseAgreement;
import com.atguigu.lease.model.enums.LeaseStatus;
import com.atguigu.lease.web.admin.service.LeaseAgreementService;
import com.baomidou.mybatisplus.core.conditions.update.LambdaUpdateWrapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;

import java.util.Date;

@Component
public class ScheduleTasks {

    @Autowired
    private LeaseAgreementService service;

    @Scheduled(cron = "0 0 0 * * *")
    public void checkLeaseStatus(){
        LambdaUpdateWrapper<LeaseAgreement> updateWrapper = new LambdaUpdateWrapper<>();
        updateWrapper.le(LeaseAgreement::getLeaseEndDate,new Date());
        updateWrapper.in(LeaseAgreement::getStatus,LeaseStatus.SIGNED,LeaseStatus.WITHDRAWING);
        updateWrapper.set(LeaseAgreement::getStatus, LeaseStatus.EXPIRED);
        service.update(updateWrapper);
    }
}