首先可以通过文档了解shedlock的一些信息 https://github.com/lukas-krecan/ShedLock

1. 引入依赖 

  ....
    <properties>
        <shedlock.version>4.19.1</shedlock.version>
    </properties>

    <!-- shedlock -->
        <dependency>
            <groupId>net.javacrumbs.shedlock</groupId>
            <artifactId>shedlock-spring</artifactId>
            <version>${shedlock.version}</version>
        </dependency>

        <dependency>
            <groupId>net.javacrumbs.shedlock</groupId>
            <artifactId>shedlock-provider-jdbc-template</artifactId>
            <version>${shedlock.version}</version>
     </dependency>

2.执行sql语句，通过外部进程提供锁 

# MySQL, MariaDB
CREATE TABLE shedlock(name VARCHAR(64) NOT NULL, lock_until TIMESTAMP(3) NOT NULL,
    locked_at TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3), locked_by VARCHAR(255) NOT NULL, PRIMARY KEY (name));

3. 编写配置

package zyy.demo.seckill.config;

import net.javacrumbs.shedlock.core.LockProvider;
import net.javacrumbs.shedlock.provider.jdbctemplate.JdbcTemplateLockProvider;
import net.javacrumbs.shedlock.spring.annotation.EnableSchedulerLock;
import net.javacrumbs.shedlock.spring.annotation.SchedulerLock;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.Scheduled;
import zyy.demo.seckill.utils.TimeUtil;

import javax.sql.DataSource;
import java.time.LocalDateTime;
import java.util.TimeZone;

/**
 * @author zyy
 * @program seckill
 * @description ${}
 * @date 2020-12-30 10:21
 **/
@Configuration
@EnableScheduling
@EnableSchedulerLock(defaultLockAtMostFor = "PT5M")
public class SchedulerConfig {

    @Scheduled(cron = "0/1 * * * * ? ")
    @SchedulerLock(name = "printTime", lockAtMostFor = "3s", lockAtLeastFor = "2s")
    public void scheduledTask() {
        /**
         通过设置lockAtMostFor，我们可以确保即使节点死亡，锁也会被释放;通过设置lockleast for，
         我们可以确保它在5秒内不会执行超过一次。请注意，lockAtMostFor只是一个安全网，
         以防执行任务的节点死亡，所以将它设置为一个明显大于最大估计执行时间的时间。
         如果任务花费的时间比lockAtMostFor长，它可能会被再次执行，结果将是不可预测的(更多的进程将持有锁)。
         * */
        String s = TimeUtil.formatTime(LocalDateTime.now());
        System.out.println(s);
    }

    @Scheduled(cron = "0/5 * * * * ? ")
    @SchedulerLock(name = "printTime2", lockAtMostFor = "10s", lockAtLeastFor = "8s")
    public void scheduledTask2() {
        String s = TimeUtil.formatTime(LocalDateTime.now());
        System.err.println(s);
    }

// ---------------------------------------------配置锁提供程序——通过外部进程提供锁，如SQL数据库、Mongo、Redis等

    @Bean
    public LockProvider lockProvider(DataSource dataSource) {
        return new JdbcTemplateLockProvider(
                JdbcTemplateLockProvider.Configuration.builder()
                        .withJdbcTemplate(new JdbcTemplate(dataSource))
                        .withTimeZone(TimeZone.getTimeZone("Asia/Shanghai"))
                        .build()
        );
    }
}

4.查看数据库