SpringBoot 集成 ShedLock 分布式锁的示例详解

CREATE TABLE shedlock(
    name VARCHAR(64), 
    lock_until TIMESTAMP(3) NULL, 
    locked_at TIMESTAMP(3) NULL, 
    locked_by  VARCHAR(255), 
    PRIMARY KEY (name)
)

<dependency>
            <groupId>net.javacrumbs.shedlock</groupId>
            <artifactId>shedlock-spring</artifactId>
            <version>2.3.0</version>
        </dependency>
        <dependency>
            <groupId>net.javacrumbs.shedlock</groupId>
            <artifactId>shedlock-provider-redis-spring</artifactId>
            <version>2.3.0</version>
        </dependency>
        
        <!--spring2.0集成redis所需common-pool2 -->
        <!-- 必须加上，jedis依赖此 若项目中已经引入jedis 请忽略此步骤-->
        <!-- Spring Boot 2.0 的操作手册有标注 大家可以去看看 地址是：https://docs.spring.io/spring-boot/docs/2.0.3.RELEASE/reference/htmlsingle/ -->
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-pool2</artifactId>
        </dependency>

 <!--spring2.0集成redis所需common-pool2 -->
        <!-- 必须加上，jedis依赖此 若项目中已经引入jedis 请忽略此步骤-->
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-pool2</artifactId>
        </dependency>

import net.javacrumbs.shedlock.core.LockProvider;
import net.javacrumbs.shedlock.provider.redis.spring.RedisLockProvider;
import net.javacrumbs.shedlock.spring.annotation.EnableSchedulerLock;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;


@Configuration
//defaultLockAtMostFor 指定在执行节点结束时应保留锁的默认时间使用ISO8601 Duration格式
//作用就是在被加锁的节点挂了时，无法释放锁，造成其他节点无法进行下一任务
//这里默认55s
//关于ISO8601 Duration格式用的不到，具体可上网查询下相关资料，应该就是一套规范，规定一些时间表达方式
@EnableSchedulerLock(defaultLockAtMostFor = "PT55S")
public class ShedLockRedisConfig {

    @Value("${spring.profiles.active}")
    private String env;

    @Bean
    public LockProvider lockProvider(RedisConnectionFactory connectionFactory) {
        //环境变量 -需要区分不同环境避免冲突，如dev环境和test环境，两者都部署时，只有一个实例进行，此时会造成相关环境未启动情况
        return new RedisLockProvider(connectionFactory, env);
    }
}

@SpringBootApplication
@EnableScheduling
public class EpidemicMessageApplication {

    public static void main(String[] args) {
        SpringApplication.run(EpidemicMessageApplication.class, args);
    }
}

//区分服务
    @Value("${server.port}")
    private String port;
    
    @Scheduled(cron = "0 */1 * * * ?")
    
    @SchedulerLock(name = "scheduledController_notice", lockAtLeastForString = "PT15M", lockAtMostForString = "PT14M")
    public StandardResult notice() {
        try {
            logger.info(port + "- 执行定时器 scheduledController_notice");
            return StandardResult.ok();
        } catch (Exception e) {
            logger.error("异常信息:", e);
            return StandardResult.faild("异常信息", e);
        }
    }