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);
     }