项目中引入SpringCache

1. pom文件引入依赖

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

2. 配置文件指定缓存类型

   spring:cache:type: redis
   

3. 启动类开启缓存注解@EnableCaching

springEl表达式

• methodName：当前被调用的方法名

  • #root.methodName

• args：当前被调用的方法的参数列表

  • #root.args[0]

• result：方法执行后的返回值

  • #result

注解使用

• Cacheable注解

  • 标记在一个方法上，也可以标记在一个类上
  • 缓存标注对象的返回结果，标注在方法上缓存该方法的返回值，标注在类上缓存该类所有的方法返回值
  • value：缓存名称，可以有多个
  • key：缓存的key规则，可以用springEL表达式，默认是方法的参数组合
  • condition：缓存条件，使用springEL编写，返回true才缓存

  @Cacheable(value = "user:page",key = "#pageNum+'_'+#pageSize")
  public Map<String, Object> page(Integer pageNum, Integer pageSize) {Map<String,Object> map = new HashMap<>();Page<User> page = new Page<>(pageNum,pageSize);Page<User> listPage = this.userMapper.selectPage(page, null);map.put("totalRecord",listPage.getTotal());map.put("totalPage",listPage.getPages());map.put("list",listPage.getRecords());return map;
  }
  

• CachePut注解：更新缓存

  @CachePut(value = "user", key = "#user.id")
  public User update(User user) {this.userMapper.updateById(user);return this.userMapper.selectById(user.getId());
  }
  

• CacheEvict注解：删除缓存

  • beforeInvocation = true：缓存清除是否在方法之前执行，默认false

  @CacheEvict(value = "user", key = "#id", beforeInvocation = true)
  public boolean delete(Integer id) {int i = 1 / 0;return this.userMapper.deleteById(id) > 0;
  }
  

• Caching

  • 组合多个Cache注解使用
  • 允许在同一方法上使用多个嵌套的@Cacheable、@CachePut、@CacheEvict注解

  @Caching(cacheable = {@Cacheable(value = "user1", key = "#user.id")},put = {@CachePut(value = "user2", key = "#user.id")})
  public User update(User user) {this.userMapper.updateById(user);return this.userMapper.selectById(user.getId());
  }
  

SpringCache框架自定义cacheManager配置过期时间

• 配置类

  /*** 过期时间1h** @param redisConnectionFactory* @return*/
  @Bean
  public RedisCacheManager redisCacheManager1Hour(RedisConnectionFactory redisConnectionFactory) {ObjectMapper objectMapper = new ObjectMapper();objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);objectMapper.registerModule(new JavaTimeModule());objectMapper.configure(MapperFeature.USE_ANNOTATIONS, false);// 只缓存非空值objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);// 将类型序列化到属性json字符串中objectMapper.activateDefaultTyping(LaissezFaireSubTypeValidator.instance, ObjectMapper.DefaultTyping.NON_FINAL, JsonTypeInfo.As.PROPERTY);Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);jackson2JsonRedisSerializer.setObjectMapper(objectMapper);RedisCacheConfiguration configuration = RedisCacheConfiguration.defaultCacheConfig().entryTtl(Duration.ofHours(1)).serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(jackson2JsonRedisSerializer));return RedisCacheManager.builder(redisConnectionFactory).cacheDefaults(configuration).transactionAware().build();
  }
  

• Service类使用

  @Cacheable(value = "user:page",key = "#pageNum+'_'+#pageSize", cacheManager = "redisCacheManager1Hour")
  public Map<String, Object> page(Integer pageNum, Integer pageSize) {Map<String,Object> map = new HashMap<>();Page<User> page = new Page<>(pageNum,pageSize);Page<User> listPage = this.userMapper.selectPage(page, null);map.put("totalRecord",listPage.getTotal());map.put("totalPage",listPage.getPages());map.put("list",listPage.getRecords());return map;
  }
  

SpringCache框架自定义keyGenerator

• key规则定义配置类

  /*** 自定义缓存key规则** @return*/
  @Bean
  public KeyGenerator keyGenerator() {return (obj, method, args) -> obj.getClass().getSimpleName() + "_" + method.getName() + "_" + StringUtils.arrayToDelimitedString(args, "_");
  }
  

• Service类使用，key和keyGenerator只能二选一

  @Cacheable(value = "user:page", keyGenerator = "keyGenerator")
  public Map<String, Object> page(Integer pageNum, Integer pageSize) {Map<String, Object> map = new HashMap<>();Page<User> page = new Page<>(pageNum, pageSize);Page<User> listPage = this.userMapper.selectPage(page, null);map.put("totalRecord", listPage.getTotal());map.put("totalPage", listPage.getPages());map.put("list", listPage.getRecords());return map;
  }