Redis监听过期的key实现流程详解

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.0</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.alian</groupId>
    <artifactId>expiration</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>expiration</name>
    <description>redis-key-expiration-listener</description>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <project.package.directory>target</project.package.directory>
        <java.version>1.8</java.version>
        <!--com.fasterxml.jackson 版本-->
        <jackson.version>2.9.10</jackson.version>
        <!--阿里巴巴fastjson 版本-->
        <fastjson.version>1.2.68</fastjson.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>
        <!--redis依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
            <version>${parent.version}</version>
        </dependency>
        <!--用于序列化-->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>${jackson.version}</version>
        </dependency>
        <!--java 8时间序列化-->
        <dependency>
            <groupId>com.fasterxml.jackson.datatype</groupId>
            <artifactId>jackson-datatype-jsr310</artifactId>
            <version>${jackson.version}</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.68</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.16.14</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.2</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

package com.alian.expiration.config;
import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateDeserializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateTimeDeserializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalTimeDeserializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateSerializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateTimeSerializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalTimeSerializer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.listener.RedisMessageListenerContainer;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;
@Configuration
public class RedisConfig {
    /**
     * redis配置
     *
     * @param redisConnectionFactory
     * @return
     */
    @Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) {
        // 实例化redisTemplate
        RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
        //设置连接工厂
        redisTemplate.setConnectionFactory(redisConnectionFactory);
        // key采用String的序列化
        redisTemplate.setKeySerializer(keySerializer());
        // value采用jackson序列化
        redisTemplate.setValueSerializer(valueSerializer());
        // Hash key采用String的序列化
        redisTemplate.setHashKeySerializer(keySerializer());
        // Hash value采用jackson序列化
        redisTemplate.setHashValueSerializer(valueSerializer());
        // 支持事务
        // redisTemplate.setEnableTransactionSupport(true);
        //执行函数，初始化RedisTemplate
        redisTemplate.afterPropertiesSet();
        return redisTemplate;
    }
    /**
     * key类型采用String序列化
     *
     * @return
     */
    private RedisSerializer<String> keySerializer() {
        return new StringRedisSerializer();
    }
    /**
     * value采用JSON序列化
     *
     * @return
     */
    private RedisSerializer<Object> valueSerializer() {
        //设置jackson序列化
        Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer<>(Object.class);
        //设置序列化对象
        jackson2JsonRedisSerializer.setObjectMapper(getMapper());
        return jackson2JsonRedisSerializer;
    }
    /**
     * 使用com.fasterxml.jackson.databind.ObjectMapper
     * 对数据进行处理包括java8里的时间
     *
     * @return
     */
    private ObjectMapper getMapper() {
        ObjectMapper mapper = new ObjectMapper();
        //设置可见性
        mapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        //默认键入对象
        mapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
        //设置Java 8 时间序列化
        JavaTimeModule timeModule = new JavaTimeModule();
        timeModule.addSerializer(LocalDateTime.class, new LocalDateTimeSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
        timeModule.addSerializer(LocalDate.class, new LocalDateSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
        timeModule.addSerializer(LocalTime.class, new LocalTimeSerializer(DateTimeFormatter.ofPattern("HH:mm:ss")));
        timeModule.addDeserializer(LocalDateTime.class, new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
        timeModule.addDeserializer(LocalDate.class, new LocalDateDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
        timeModule.addDeserializer(LocalTime.class, new LocalTimeDeserializer(DateTimeFormatter.ofPattern("HH:mm:ss")));
        //禁用把时间转为时间戳
        mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
        mapper.registerModule(timeModule);
        return mapper;
    }
    @Bean
    RedisMessageListenerContainer container(RedisConnectionFactory connectionFactory) {
        RedisMessageListenerContainer container = new RedisMessageListenerContainer();
        container.setConnectionFactory(connectionFactory);
        return container;
    }
}

package com.alian.expiration.listener;
import com.alian.expiration.service.RedisExpirationService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.connection.Message;
import org.springframework.data.redis.listener.KeyExpirationEventMessageListener;
import org.springframework.data.redis.listener.RedisMessageListenerContainer;
import org.springframework.stereotype.Component;
@Slf4j
@Component
public class RedisKeyExpirationListener extends KeyExpirationEventMessageListener {
    @Autowired
    private RedisExpirationService redisExpirationService;
	// 把我们上面一步配置的bean注入进去
    public RedisKeyExpirationListener(RedisMessageListenerContainer listenerContainer) {
        super(listenerContainer);
    }
    /**
     * 针对redis数据失效事件，进行数据处理
     *
     * @param message
     * @param pattern
     */
    @Override
    public void onMessage(Message message, byte[] pattern) {
        // 用户做自己的业务处理即可,注意message.toString()可以获取失效的key
        String expiredKey = message.toString();
        log.info("onMessage --> redis 过期的key是：{}", expiredKey);
        try {
            // 对过期key进行处理
            redisExpirationService.processingExpiredKey(expiredKey);
            log.info("过期key处理完成：{}", expiredKey);
        } catch (Exception e) {
            e.printStackTrace();
            log.error("处理redis 过期的key异常：{}", expiredKey, e);
        }
    }
}

package com.alian.expiration.service;
import com.alian.expiration.util.SignUtils;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;
import java.util.concurrent.TimeUnit;
@Slf4j
@Service
public class RedisExpirationService {
    @Autowired
    private RedisTemplate<String, Object> redisTemplate;
    public void processingExpiredKey(String expiredKey) {
        // 如果是优惠券的key(一定要规范命名)
        if (expiredKey.startsWith("com.mall.coupon.id")) {
            // 临时key,此key可以在业务处理完，然后延迟一定时间删除，或者不处理
            String tempKey = SignUtils.md5(expiredKey, "UTF-8");
            // 临时key不存在才设置值，key超时时间为10秒（此处相当于分布式锁的应用）
            Boolean exist = redisTemplate.opsForValue().setIfAbsent(tempKey, "1", 10, TimeUnit.SECONDS);
            if (Boolean.TRUE.equals(exist)) {
                log.info("Business Handing...");
                // 比如截取里面的id，然后关联数据库进行处理
            } else {
                log.info("Other service is handing...");
            }
        } else {
            log.info("Expired keys without processing");
        }
    }
}

package com.alian.expiration.util;
import java.security.MessageDigest;
public class SignUtils {
    public static final String md5(String s, String charset) {
        char[] hexDigits = new char[]{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
        try {
            byte[] btInput = s.getBytes(charset);
            MessageDigest mdInst = MessageDigest.getInstance("MD5");
            mdInst.update(btInput);
            byte[] md = mdInst.digest();
            int j = md.length;
            char[] str = new char[j * 2];
            int k = 0;
            for (byte byte0 : md) {
                str[k++] = hexDigits[byte0 >>> 4 & 15];
                str[k++] = hexDigits[byte0 & 15];
            }
            return new String(str);
        } catch (Exception var11) {
            return "";
        }
    }
}

package com.alian.expiration;
import lombok.extern.slf4j.Slf4j;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;
@Slf4j
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest
public class RedisKeyExpirationTest {
    @Autowired
    private RedisTemplate<String, Object> redisTemplate;
    @Test
    public void keyExpiration() {
        // 优惠券信息
        String id = "2023021685264735";
        Map<String, String> map = new HashMap<>();
        map.put("id", id);
        map.put("amount", "1000");
        map.put("type", "1001");
        map.put("describe", "满减红包");
        // 缓存到redis
        redisTemplate.opsForHash().putAll("com.mall.coupon.id." + id, map);
        // 设置过期时间
        redisTemplate.expire("com.mall.coupon.id." + id, 10, TimeUnit.SECONDS);
    }
}