使用@Scheduled实现定时任务

用一个实现签到功能的Demo工程为例

1.SignApplication 启动类

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.annotation.EnableScheduling;

/**
 * @author hzc8893 2023/1/2 12:25
 * @EnableAsync 使用异步方法
 * @EnableScheduling 开启任务
 */
@SpringBootApplication
@EnableAsync
@EnableScheduling
public class SignApplication {

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

2.RedisConfig Redis序列化配置类

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;

/**
 * @author hzc8893 2023/1/2 12:25
 */
@Configuration
public class RedisConfig {
    /**
     * springboot 默认帮我们创建的RedisTemplate的key和value的序列化方式是jdk默认的方式,
     * 我们有时候手动向redis中添加的数据可能无法被查询解析出来,所以我们需要修改序列化方式
     * @param connectionFactory
     * @return
     */
    @Bean
    public RedisTemplate<String, Object> redisTemplate(LettuceConnectionFactory connectionFactory) {
        RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
        redisTemplate.setConnectionFactory(connectionFactory);
        StringRedisSerializer stringRedisSerializer = new StringRedisSerializer();
        redisTemplate.setKeySerializer(stringRedisSerializer); //设置key的序列化方式
        redisTemplate.setHashKeySerializer(stringRedisSerializer);//设置hash类型的数据的key的序列化方式

        Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
        ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        objectMapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);//非final类型的数据才会被序列化
        jackson2JsonRedisSerializer.setObjectMapper(objectMapper);

        redisTemplate.setValueSerializer(jackson2JsonRedisSerializer);//设置value的序列化方式为json
        redisTemplate.setHashValueSerializer(jackson2JsonRedisSerializer);

        return redisTemplate;
    }
}

3.MyTask 定时任务配置类

@Scheduled 中需要使用cron表达式

可以去这个网站上便捷生成Cron表达式:quartz/Cron/Crontab表达式在线生成工具-BeJSON.com

我使用的cron表达式"20 * * * * ?", 表示会在每分钟的第20秒执行该定时任务去删除Redis中的对应数据

import com.hzc.contant.SignPrefix;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.Scheduled;

import java.util.Set;

/**
 * @author hzc8893 2023/1/2 12:25
 */
@Configuration
public class MyTask {
    @Autowired
    private RedisTemplate redisTemplate;

    @Async
    @Scheduled(cron = "20 * * * * ?")
    public void myTask() {
        Set<String> keys = redisTemplate.keys(SignPrefix.SIGN_PREFIX + "*");
        if (keys != null) {
            redisTemplate.delete(keys);
        }
    }
}