7 Timer (springboot)

1 In the startup class add annotations: @EnableScheduling

package com.imooc.springboot.study;


import org.springframework.boot.Banner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.WebApplicationType;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.annotation.EnableScheduling;

@EnableScheduling
@SpringBootApplication
public class SpringBootStudyApplication {
    public static void main(String[] args) {
        // 1. 通过静态 run 方法
        SpringApplication.run(SpringBootStudyApplication.class, args);

}

2 Use

package com.imooc.springboot.study.schedule;


import lombok.extern.slf4j.Slf4j;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

@Slf4j
@Component
public class BootSchedule {

    private final DateTimeFormatter fmt = DateTimeFormatter.ofPattern(
            "HH:mm:ss"
    );


    /**
     * <h2>上一次开始执行时间点之后3000毫秒再执行</h2>
     * */
    @Scheduled(fixedRate = 3000)
    public void schedule01() {
        log.info("schedule01 -> {}", LocalDateTime.now().format(fmt));
    }


    /**
     * <h2>上一次执行完毕时间点之后3s再执行</h2>
     * */
    @Scheduled(fixedDelay = 3000)
    public void schedule02() {
        log.info("schedule02 -> {}", LocalDateTime.now().format(fmt));
    }


    /**
     * <h2>第一次延迟2s之后执行, 之后按照每3s执行一次</h2>
     * */
    @Scheduled(initialDelay = 2000, fixedRate = 3000)
    public void schedule03() {
        log.info("schedule03 -> {}", LocalDateTime.now().format(fmt));
    }


    /**
     * <h2>每3s执行一次</h2>
     * */
    @Scheduled(cron = "*/3 * * * * ?")
    public void schedule04() {
        log.info("schedule04 -> {}", LocalDateTime.now().format(fmt));
    }
}

Computing cron
http://cron.qqe2.com/