spring cache + redis 實(shí)現(xiàn)系統(tǒng)緩存

spring cache定義了緩存接口，redis則作為緩存的實(shí)現(xiàn)

1.引入 spring cache 和 redis

<!-- spring boot--> 
<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.0.RELEASE</version>
    <relativePath/>
</parent>
<!-- spring cache -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-cache</artifactId>
</dependency>
<!-- redis -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
<!-- 為了解決 ClassNotFoundException: org.apache.commons.pool2.impl.GenericObjectPoolConfig -->
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-pool2</artifactId>
    <version>2.5.0</version>
</dependency>

2. yaml配置

spring: 
    redis:
    #數(shù)據(jù)庫索引
    database: 0
    host: 127.0.0.1
    port: 6379
    password:
    #連接超時(shí)時(shí)間
    timeout: 5000

3.redis緩存配置類

package me.zhengjie.config;

import cn.hutool.core.lang.Assert;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.parser.ParserConfig;
import com.alibaba.fastjson.serializer.SerializerFeature;
import lombok.extern.slf4j.Slf4j;
import me.zhengjie.utils.StringUtils;
import org.apache.commons.codec.digest.DigestUtils;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.data.redis.RedisProperties;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.cache.Cache;
import org.springframework.cache.annotation.CachingConfigurerSupport;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cache.interceptor.CacheErrorHandler;
import org.springframework.cache.interceptor.KeyGenerator;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheConfiguration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisOperations;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.RedisSerializationContext;
import org.springframework.data.redis.serializer.RedisSerializer;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.time.Duration;
import java.util.HashMap;
import java.util.Map;

/**
 * 緩存配置類
 * @date 2018-11-24
 */
@Slf4j
@Configuration
@EnableCaching
@ConditionalOnClass(RedisOperations.class)
@EnableConfigurationProperties(RedisProperties.class)
public class RedisConfig extends CachingConfigurerSupport {

    /**
     *  設(shè)置 redis 數(shù)據(jù)默認(rèn)過期時(shí)間，默認(rèn)6小時(shí)
     *  設(shè)置@cacheable 序列化方式
     */
    @Bean
    public RedisCacheConfiguration redisCacheConfiguration(){
        FastJsonRedisSerializer<Object> fastJsonRedisSerializer = new FastJsonRedisSerializer<>(Object.class);
        RedisCacheConfiguration configuration = RedisCacheConfiguration.defaultCacheConfig();
        configuration = configuration.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(fastJsonRedisSerializer)).entryTtl(Duration.ofHours(6));
        return configuration;
    }

    @Bean(name = "redisTemplate")
    @ConditionalOnMissingBean(name = "redisTemplate")
    public RedisTemplate<Object, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) {
        RedisTemplate<Object, Object> template = new RedisTemplate<>();
        //序列化
        FastJsonRedisSerializer<Object> fastJsonRedisSerializer = new FastJsonRedisSerializer<>(Object.class);
        // value值的序列化采用fastJsonRedisSerializer
        template.setValueSerializer(fastJsonRedisSerializer);
        template.setHashValueSerializer(fastJsonRedisSerializer);
        // 全局開啟AutoType，這里方便開發(fā)，使用全局的方式
        ParserConfig.getGlobalInstance().setAutoTypeSupport(true);
        // 建議使用這種方式，小范圍指定白名單
//        ParserConfig.getGlobalInstance().addAccept("me.zhengjie.domain");
//        ParserConfig.getGlobalInstance().addAccept("me.zhengjie.modules.system.service.dto");
//        ParserConfig.getGlobalInstance().addAccept("me.zhengjie.service.dto");
//        ParserConfig.getGlobalInstance().addAccept("me.zhengjie.modules.system.domain");
//        ParserConfig.getGlobalInstance().addAccept("me.zhengjie.modules.quartz.domain");
//        ParserConfig.getGlobalInstance().addAccept("me.zhengjie.modules.monitor.domain");
//        ParserConfig.getGlobalInstance().addAccept("me.zhengjie.modules.security.security");
        // key的序列化采用StringRedisSerializer
        template.setKeySerializer(new StringRedisSerializer());
        template.setHashKeySerializer(new StringRedisSerializer());
        template.setConnectionFactory(redisConnectionFactory);
        return template;
    }

    /**
     * 自定義緩存key生成策略，默認(rèn)將使用該策略
     */
    @Bean
    @Override
    public KeyGenerator keyGenerator() {
        return (target, method, params) -> {
            Map<String,Object> container = new HashMap<>();
            Class<?> targetClassClass = target.getClass();
            // 類地址
            container.put("class",targetClassClass.toGenericString());
            // 方法名稱
            container.put("methodName",method.getName());
            // 包名稱
            container.put("package",targetClassClass.getPackage());
            // 參數(shù)列表
            for (int i = 0; i < params.length; i++) {
                container.put(String.valueOf(i),params[i]);
            }
            // 轉(zhuǎn)為JSON字符串
            String jsonString = JSON.toJSONString(container);
            // 做SHA256 Hash計(jì)算，得到一個(gè)SHA256摘要作為Key
            return DigestUtils.sha256Hex(jsonString);
        };
    }

    @Bean
    @Override
    public CacheErrorHandler errorHandler() {
        // 異常處理，當(dāng)Redis發(fā)生異常時(shí)，打印日志，但是程序正常走
        log.info("初始化 -> [{}]", "Redis CacheErrorHandler");
        return new CacheErrorHandler() {
            @Override
            public void handleCacheGetError(RuntimeException e, Cache cache, Object key) {
                log.error("Redis occur handleCacheGetError：key -> [{}]", key, e);
            }

            @Override
            public void handleCachePutError(RuntimeException e, Cache cache, Object key, Object value) {
                log.error("Redis occur handleCachePutError：key -> [{}]；value -> [{}]", key, value, e);
            }

            @Override
            public void handleCacheEvictError(RuntimeException e, Cache cache, Object key) {
                log.error("Redis occur handleCacheEvictError：key -> [{}]", key, e);
            }

            @Override
            public void handleCacheClearError(RuntimeException e, Cache cache) {
                log.error("Redis occur handleCacheClearError：", e);
            }
        };
    }

}

/**
 * Value 序列化
 *
 * @author /
 * @param <T>
 */
 class FastJsonRedisSerializer<T> implements RedisSerializer<T> {

    private Class<T> clazz;

    FastJsonRedisSerializer(Class<T> clazz) {
        super();
        this.clazz = clazz;
    }

    @Override
    public byte[] serialize(T t) {
        if (t == null) {
            return new byte[0];
        }
        return JSON.toJSONString(t, SerializerFeature.WriteClassName).getBytes(StandardCharsets.UTF_8);
    }

    @Override
    public T deserialize(byte[] bytes) {
        if (bytes == null || bytes.length <= 0) {
            return null;
        }
        String str = new String(bytes, StandardCharsets.UTF_8);
        return JSON.parseObject(str, clazz);
    }

}

/**
 * 重寫序列化器
 *
 * @author /
 */
class StringRedisSerializer implements RedisSerializer<Object> {

    private final Charset charset;

    StringRedisSerializer() {
        this(StandardCharsets.UTF_8);
    }

    private StringRedisSerializer(Charset charset) {
        Assert.notNull(charset, "Charset must not be null!");
        this.charset = charset;
    }

    @Override
    public String deserialize(byte[] bytes) {
        return (bytes == null ? null : new String(bytes, charset));
    }

    @Override
    public byte[] serialize(Object object) {
        String string = JSON.toJSONString(object);
        if (StringUtils.isBlank(string)) {
            return null;
        }
        string = string.replace("\"", "");
        return string.getBytes(charset);
    }
}

4.service層緩存注解

@Service
@CacheConfig(cacheNames = "user")
@Transactional(propagation = Propagation.SUPPORTS, readOnly = true, rollbackFor = Exception.class)
public class UserServiceImpl implements UserService {
    @Override
    @Cacheable
    public List<UserDTO> queryAll(UserQueryCriteria criteria) {
        List<User> users = userRepository.findAll((root, criteriaQuery, criteriaBuilder) -> QueryHelp.getPredicate(root,criteria,criteriaBuilder));
        return userMapper.toDto(users);
    }
}

5.生成的緩存展示

5.1 從可視化redis客戶端查詢展示

[圖片上傳失敗...(image-137e9f-1591627344874)]

5.2 從dos客戶端查詢展示

[圖片上傳失敗...(image-2f98e7-1591627344874)]

6.注解說明

  • @Cacheable:觸發(fā)緩存寫入。
  • @CacheEvict:觸發(fā)緩存清除。
  • @CachePut:更新緩存(不會(huì)影響到方法的運(yùn)行)。
  • @Caching:重新組合要應(yīng)用于方法的多個(gè)緩存操作。
  • @CacheConfig:設(shè)置類級(jí)別上共享的一些常見緩存設(shè)置。

7. 可參考博客：springboot整合spring @Cache和Redis

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