SpringBoot使用Redis缓存

（1）、添加依赖

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

（2）、配置Redis

spring.redis.host=192.168.205.128

（3）、使用

配置好Redis后，缓存注解就会把数据缓存到Redis中了，如果我们想要手动添加缓存可以使用

• StringRedisTemplate　　仅仅操作字符串

• RedisTemplate　　操作Key-Value对象

**Redis默认使用Jdk序列化机制（将对象序列化到Redis中必须要实现Serializable接口且缓存的数据是二进制），若要将数据以Json的形式序列化，可采用以下两种方式

　　1.使用第三方jar包将对象转化为json

　　2.更改redisTemplate默认的序列化规则

package cn.coreqi.config;

import cn.coreqi.entities.User;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.data.redis.cache.RedisCacheConfiguration;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.cache.RedisCacheWriter;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializationContext;
import org.springframework.data.redis.serializer.RedisSerializer;

import java.time.Duration;

@Configuration
public class MyRedisConfig {
    @Bean
    public RedisTemplate<Object, User> userRedisTemplate(RedisConnectionFactory redisConnectionFactory){
        RedisTemplate<Object, User> template = new RedisTemplate<>();
        template.setConnectionFactory(redisConnectionFactory);
        template.setDefaultSerializer(new Jackson2JsonRedisSerializer<User>(User.class));
        return template;
    }

    @Primary
    @Bean
    public RedisCacheManager userCacheManager(RedisConnectionFactory redisConnectionFactory) {
        //初始化一个RedisCacheWriter
        RedisCacheWriter redisCacheWriter = RedisCacheWriter.nonLockingRedisCacheWriter(redisConnectionFactory);
        //设置CacheManager的值序列化方式为json序列化
        RedisSerializer<Object> jsonSerializer = new GenericJackson2JsonRedisSerializer();
        RedisSerializationContext.SerializationPair<Object> pair = RedisSerializationContext.SerializationPair
                .fromSerializer(jsonSerializer);
        RedisCacheConfiguration defaultCacheConfig=RedisCacheConfiguration.defaultCacheConfig()
                .serializeValuesWith(pair);
        //设置默认超过期时间是30秒
        defaultCacheConfig.entryTtl(Duration.ofSeconds(30));
        //初始化RedisCacheManager
        return new RedisCacheManager(redisCacheWriter, defaultCacheConfig);
    }
}

@Service
@CacheConfig(cacheNames = "user",cacheManager = "userCacheManager")   //抽取缓存的公共配置
//可以使用@Caching注解在方法上运用多个缓存注解
public class UserService {
  .......      
}

*如何在代码中获取缓存

    @Qualifier("userCacheManager")
    @Autowired
    private RedisCacheManager userCacheManager;

    public User cache(){
        Cache user = userCacheManager.getCache("user");
        user.put("2",new User("gaoxing","fanqisoft",1));
        return user.get("1",User.class);
    }