整合redis

• springboot在现在的版本中操作Redis数据库用到了lettuce，而不是Jedis，他们各有各的特点。
• Jedis以Redis命令作为方法名称，学习成本低，简单实用。但是Jedis实例是线程不安全的，多线程环境下需要基于连接池来使用。
• Lettuce是基于Netty实现的，支持同步、异步和响应式编程方式，并且是线程安全的。支持Redis的哨兵模式、集群模式和管道模式。

SpringDataRedis相关的api

1、引入依赖

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

2、配置文件

spring:
  redis:
    # Redis服务器地址
    host: 127.0.0.1
    # Redis服务器端口号
    port: 6379
    # 使用的数据库索引，默认是0
    database: 0
    # 连接超时时间
    timeout: 1800000
     # 设置密码
    password: "123456"

3、代码测试

    @Autowired
    private RedisTemplate redisTemplate;
    @Test
    public void redis() {
        redisTemplate.opsForValue().set("study","学习redis");
        String name = (String) redisTemplate.opsForValue().get("study");
        System.out.println(name); 
    }

问题出现了：当我们使用Redis客户端查看刚刚存入Redis数据库的数据时，结果是这样的：

是因为在使用默认的对象redisTemplate时，会把value值序列化为byte类型，所以就出现了上图的结果。

同理，如果我们存储内容是对象的时候，不序列化的话会报错

因此我们需要自定义序列化器

    public void redis(){
        User user = new User();
        user.setName("zs");
        user.setDeptId("11");
        user.setAge(20);
        redisTemplate.opsForValue().set("user:info",user);
    }

报错：

因此我们需要自定义序列化器

4、自定义序列化器

@Configuration
public class RedisCacheManagerConfig {

    @Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) {
        RedisTemplate<String, Object> template = new RedisTemplate<>();
        template.setConnectionFactory(factory);

        // 设置Key的序列化方式
        template.setKeySerializer(new StringRedisSerializer());
        // 设置Value的序列化方式，根据需求选择
        template.setValueSerializer(jackson2JsonRedisSerializer());

        // 同样可以设置hashKey和hashValue的序列化方式
        template.setHashKeySerializer(new StringRedisSerializer());
        template.setHashValueSerializer(new Jackson2JsonRedisSerializer<>(Object.class));

        return template;
    }


    // 配置Jackson2JsonRedisSerializer
    // 避免出现获取缓存时出现的类型转换错误
    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);

        // 此项必须配置，否则会报java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to XXX
        objectMapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL, JsonTypeInfo.As.PROPERTY);
        objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
        jackson2JsonRedisSerializer.setObjectMapper(objectMapper);
        return jackson2JsonRedisSerializer;
    }

}

再次执行存储对象，存储字符串

整合redisCahemanager

在上述redis配置中增加cacheMangerp配置

@Configuration
public class RedisCacheManagerConfig {
    @Bean
    public CacheManager cacheManager(RedisConnectionFactory connectionFactory) {
        // 若想存入的不包含类信息，就直接使用GenericJackson2JsonRedisSerializer，配合ObjectMapper
        ObjectMapper objectMapper = new ObjectMapper(); 
        GenericJackson2JsonRedisSerializer serializer = new GenericJackson2JsonRedisSerializer(objectMapper);
        //------------------------//
        RedisCacheConfiguration cacheConfiguration = RedisCacheConfiguration.defaultCacheConfig()
                .serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(jackson2JsonRedisSerializer()))
                //变双冒号为单冒号
                .computePrefixWith(name -> name +":");

        return RedisCacheManager.builder(connectionFactory)
                .cacheDefaults(cacheConfiguration)
                .build();
    }

    @Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) {
        RedisTemplate<String, Object> template = new RedisTemplate<>();
        template.setConnectionFactory(factory);

        // 设置Key的序列化方式
        template.setKeySerializer(new StringRedisSerializer());
        // 设置Value的序列化方式，根据需求选择
        template.setValueSerializer(jackson2JsonRedisSerializer());

        // 同样可以设置hashKey和hashValue的序列化方式
        template.setHashKeySerializer(new StringRedisSerializer());
        template.setHashValueSerializer(new Jackson2JsonRedisSerializer<>(Object.class));

        return template;
    }


    // 配置Jackson2JsonRedisSerializer
    // 避免出现获取缓存时出现的类型转换错误
    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);

        // 此项必须配置，否则会报java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to XXX
        objectMapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL, JsonTypeInfo.As.PROPERTY);
        objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
        jackson2JsonRedisSerializer.setObjectMapper(objectMapper);
        return jackson2JsonRedisSerializer;
    }

}

使用参考springCache本地缓存：

SpringCache之本地缓存-CSDN博客

简单测试：

@Component
public class UserCache {

    @Cacheable(cacheNames = "room")
    public User getUserId(String userId){
        User user = new User();
        user.setId(userId);
        user.setAge(10);
        user.setDeptId("1");
        user.setName("zs");
        user.setSex("男");
        return user;
    }
}


    @Autowired
    private UserCache userCache;

    @Test
    public void cache(){
        User user = userCache.getUserId("1");
        System.out.println(user);
    }

结果：