项目中使用reids后，要做整个流程的缓存的时候，发现很多接口要加缓存，代码如下：

    @Override
    public Shop getShopInfo(Long id) {
        String redisKey = String.format("o2o:shop:", id);
        Object obj = redisService.get(redisKey);
        if (ObjectUtils.isNotEmpty(obj)) {
            return JSON.parseObject(JSON.toJSONString(obj),Shop.class);
        }
        Shop shop = shopMapper.getShopInfo(id);
        redisService.add(redisKey,shop);
        return shop;
    }

这种方法使用redis没有问题，但是代码写的太多了，所以我在项目中使用了RedisCacheMager,

最后代码结构如下：

    @Override
    @Cacheable(value = "o2o:shop",key = "#id",unless = "#result == null ")
    public Shop getShopInfo(Long id) {
        Shop shop = shopMapper.getShopInfo(id);
        return shop;
    }

redis中的结果为

 数据修改，同步redis,代码为

@Override
@CachePut(value = "o2o:shop",key = "#shop.id",unless = "#result == null ")
public Shop saveOrUpdate(Shop shop) {
    Shop shop = shopMapper.addOrUpdate(shop);
    return shop;
}

通过配置减少了操作redis的代码。

代码改造步骤如下：

1. pom.xml 中存在redis的jar包

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

2. 启动类上添加注解@EnableCaching

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

3. redis 的 配置类中添加CacheManger
 

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.MapperFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
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.cache.RedisCacheManager;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.HashOperations;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializationContext;
import org.springframework.data.redis.serializer.StringRedisSerializer;

import java.lang.reflect.Method;
import java.time.Duration;


@Configuration
@EnableAutoConfiguration
public class RedisConfig {

    /**
     * 注入 RedisConnectionFactory
     */
    @Autowired
    RedisConnectionFactory redisConnectionFactory;

    /**
     * 实例化 RedisTemplate 对象
     *
     * @return
     */
    @Bean
    public RedisTemplate<String, Object> functionDomainRedisTemplate() {
        RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
		redisTemplate.setKeySerializer(new StringRedisSerializer());
        redisTemplate.setHashKeySerializer(new StringRedisSerializer());
        redisTemplate.setHashValueSerializer(jackson2JsonRedisSerializer);
        redisTemplate.setValueSerializer(jackson2JsonRedisSerializer);
        redisTemplate.setConnectionFactory(factory);
        return redisTemplate;
    }

	/**
	* 配置cacheManager
	* 
	*/
    @Bean(name = "cacheManager")
    public RedisCacheManager cacheManager(RedisConnectionFactory factory) {
		//默认的redisCahce配置，此处我们没用，而是自己配置
		//RedisCacheConfiguration.defaultCacheConfig(); 
		
        RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig()
                // 设置缓存的默认过期时间
                .entryTtl(Duration.ofSeconds(180))
                .serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(new StringRedisSerializer()))
                .serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(this.jackson2JsonRedisSerializer()))
                // 不缓存空值
                .disableCachingNullValues()
                ;
        //根据redis缓存配置和reid连接工厂生成redis缓存管理器
        RedisCacheManager redisCacheManager = RedisCacheManager.builder(factory)
                .cacheDefaults(config)
                .transactionAware()
                .build();
        return redisCacheManager;
    }
	
	 /***
     * 配置jackson2JsonRedisSerializer
     * @return
     */
    private Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer() {
        Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer =
                new Jackson2JsonRedisSerializer<>(Object.class);
        ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        objectMapper.configure(MapperFeature.USE_ANNOTATIONS, false);
        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        objectMapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
        objectMapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL, JsonTypeInfo.As.PROPERTY);
        objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
        jackson2JsonRedisSerializer.setObjectMapper(objectMapper);
        return jackson2JsonRedisSerializer;
    }

    /**
     * 重新定义KeyGenerator.
     */
    @Bean
    public KeyGenerator keyGenerator() {
        return new KeyGenerator() {
            @Override
            public Object generate(Object target, Method method, Object... params) {
                StringBuilder sb = new StringBuilder();
                sb.append(target.getClass().getName());
                sb.append(method.getName());
                for (Object obj : params) {
                    sb.append(obj.toString());
                }
                return sb.toString();
            }
        };
    }
}

解释说明：

private Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer() {}

此方法一定要配置，这是修改ObjectMapper，默认的ObjectMapper会将Redis中的字符串反序列化为java.util.LinkedHashMap类。导致后续Spring对其进行转换时会报错，java.util.LinkedHashMap cannot be cast to  xxx.xxx.xxx.class

如果使用 keyGenerator,形成的key为
 

@Cacheable(value = "o2o:shop",keyGenerator = "keyGenerator",unless = "#result == null ")