10、SpringBoot中使用Redis

冷不防 2021-11-11 06:40 279阅读 0赞

## 1、在`pom.xml`文件中引入Redis ##

<dependency>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-data-redis</artifactId>
          <version>2.1.6.RELEASE</version>
    </dependency>

`aaplcation.yml`文件配置Redis

spring:
      datasource:
        url: jdbc:mysql://localhost:3306/springboot_cache?serverTimezone=UTC
        username: root
        password: 123456
      redis:
        host: 127.0.0.1
        port: 6379

## 2、Redis简单的测试 ##

@RunWith(SpringRunner.class)
    @SpringBootTest
    public class SpringbootAdvanceCacheApplicationTests { 
    
        @Autowired
        EmployeeMapper employeeMapper;
    
    
        @Autowired
        StringRedisTemplate stringRedisTemplate;  //操作 K-V都是字符串
    
    
        @Autowired
        RedisTemplate redisTemplate;  //K-V都是对象
    
        @Test
        public void test(){ 
            stringRedisTemplate.opsForValue().append("msg","hello");
        }
    
    
        @Test
        public void test01(){ 
            String msg = stringRedisTemplate.opsForValue().get("msg");
            System.out.printf("=="+msg);
        }
    }

![e6mS0S.png][]

![e6mPYj.png][]

## 3、将Redis应用到我们业务中 ##

新建一个RddisConfig类

@Configuration
    @EnableCaching
    public class RedisConfig extends CachingConfigurerSupport { 
    
        @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();
                }
            };
        }
    }

`Service`层代码

@Cacheable(cacheNames = { "emp"})
       public Employee getEmpById(Integer id){ 
           System.out.println("查询"+id+"号员工");
           Employee employee = employeeMapper.getEmpById(id);
           return employee;
       }

#### 记得在实体类上实现序列化！！！ ####

public class Employee implements Serializable

不然会报

org.springframework.data.redis.serializer.SerializationException: Cannot serialize; nested exception is org.springframework.core.serializer.support.SerializationFailedException: Failed to serialize object using DefaultSerializer; nested exception is java.lang.IllegalArgumentException:DefaultSerializer requires a Serializable payload but received an object of type\[com.bx.cloud.common.auth.component.AuthSession\]

然后运行程序  
![e6nyG9.png][]  
我们发现存入Redis中是我们一些看不懂的，那么我们来将结果以`json`的方式存到Redis中

##### 参考这篇文章：[https://blog.csdn.net/caojidasabi/article/details/83059642][https_blog.csdn.net_caojidasabi_article_details_83059642] #####

在我们上面编写的RedisConfig类中添加我们自定义的cacheManager方法

@Configuration
        public class MyRedisConfig { 
            @Bean
            public RedisTemplate<Object, Employee> empRedisTemplate(
                    RedisConnectionFactory redisConnectionFactory)
                    throws UnknownHostException { 
                RedisTemplate<Object, Employee> template = new RedisTemplate<Object, Employee>();
                template.setConnectionFactory(redisConnectionFactory);
                Jackson2JsonRedisSerializer<Employee> jsonRedisSerializer = new Jackson2JsonRedisSerializer<Employee>(Employee.class);
                template.setDefaultSerializer(jsonRedisSerializer);
                return template;
            }
        }
        //自定义cacheManager缓存管理器
        @Bean
        public CacheManager cacheManager(RedisConnectionFactory factory)
        { 
            RedisSerializer<String> redisSerializer = new StringRedisSerializer();
            Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
    
            //解决查询缓存转换异常的问题
            ObjectMapper om = new ObjectMapper();
            om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
            om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
            jackson2JsonRedisSerializer.setObjectMapper(om);
    
            //配置序列化(解决乱码的问题)
            RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig()
                    .entryTtl(Duration.ZERO)
                    .serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(redisSerializer))
                    .serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(jackson2JsonRedisSerializer))
                    .disableCachingNullValues();
    
            RedisCacheManager cacheManager = RedisCacheManager.builder(factory)
                    .cacheDefaults(config)
                    .build();
            return cacheManager;
        }

然后就会发现Redis中存储的是json形式的啦~  
![e6KS0K.png][]

[e6mS0S.png]: /images/20211109/d4e4c8da2f7346769571b8cd53f78b0c.png
[e6mPYj.png]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly9zMi5heDF4LmNvbS8yMDE5LzA4LzA0L2U2bVBZai5wbmc
[e6nyG9.png]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly9zMi5heDF4LmNvbS8yMDE5LzA4LzA0L2U2bnlHOS5wbmc
[https_blog.csdn.net_caojidasabi_article_details_83059642]: https://blog.csdn.net/caojidasabi/article/details/83059642
[e6KS0K.png]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly9zMi5heDF4LmNvbS8yMDE5LzA4LzA0L2U2S1MwSy5wbmc