在Spring Boot微服务使用ValueOperations操作Redis String字符串

刺骨的言语ヽ痛彻心扉 2024-04-23 03:03 13阅读 0赞

**记录**：401

**场景**：在Spring Boot微服务使用RedisTemplate的ValueOperations操作Redis String字符串。

**版本**：JDK 1.8,Spring Boot 2.6.3,redis-6.2.5

**1.微服务中****Redis配置信息**

**1.1在application.yml中Redis配置信息**

spring:
      redis:
        host: 192.168.19.203
        port: 28001
        password: 12345678
        timeout: 50000

**1.2加载简要逻辑**

Spring Boot微服务在启动时，自动注解机制会读取application.yml的注入到RedisProperties对象。在Spring环境中就能取到Redis相关配置信息了。

类全称：org.springframework.boot.autoconfigure.data.redis.RedisProperties

**1.3在pom.xml添加依赖**

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

**2.配置RedisTemplate**

**2.1配置RedisTemplate**

@Configuration
    public class RedisConfig {
      @Bean("redisTemplate")
      public RedisTemplate<String, Object> redisTemplate(LettuceConnectionFactory lettuceConnectionFactory) {
          // 1.创建RedisTemplate对象
          RedisTemplate<String, Object> redisTemplate = new RedisTemplate<String, Object>();
          // 2.加载Redis配置
          redisTemplate.setConnectionFactory(lettuceConnectionFactory);
          // 3.配置key序列化
          RedisSerializer<?> stringRedisSerializer = new StringRedisSerializer();
          redisTemplate.setKeySerializer(stringRedisSerializer);
          redisTemplate.setHashKeySerializer(stringRedisSerializer);
          // 4.配置Value序列化
          Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer<Object>(Object.class);
          ObjectMapper objMapper = new ObjectMapper();
          objMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
          objMapper.activateDefaultTyping(objMapper.getPolymorphicTypeValidator(), ObjectMapper.DefaultTyping.NON_FINAL);
          jackson2JsonRedisSerializer.setObjectMapper(objMapper);
          redisTemplate.setValueSerializer(jackson2JsonRedisSerializer);
          redisTemplate.setHashValueSerializer(jackson2JsonRedisSerializer);
          // 5.初始化RedisTemplate
          redisTemplate.afterPropertiesSet();
          return redisTemplate;
      }
      @Bean
      public ValueOperations<String, Object> valueOperations(RedisTemplate<String, Object> redisTemplate) {
        return redisTemplate.opsForValue();
      }
    }

**2.2解析**

在配置RedisTemplate后，在Spring环境中，可以@Autowired自动注入方式注入操作Redis对象。比如：RedisTemplate、ValueOperations。

**3.使用ValueOperations操作Redis String字符串**

**3.1简要说明**

使用ValueOperations操作字符串，常用操作：增、查、改、删、设置超时等。

**3.2操作示例**

@RestController
    @RequestMapping("/hub/example/load")
    @Slf4j
    public class LoadController {
      @Autowired
      private RedisTemplate redisTemplate;
      @Autowired
      private ValueOperations valueOperations;
      /**
       * 操作String,使用ValueOperations
       * 对应写命令: SET key value
       * 对应读命令: GET key
       */
      @GetMapping("/valueOperations")
      public Object loadData02() {
        log.info("ValueOperations操作开始...");
        // 1.增
        valueOperations.set("CityInfo:Hangzhou02", "杭州");
        valueOperations.set("CityInfo:Hangzhou02", "苏州");
        // 2.查
        Object result01 = valueOperations.get("CityInfo:Hangzhou02");
        log.info("result01 = " + result01.toString());
        // 3.改
        valueOperations.set("CityInfo:Hangzhou02", "杭州-西湖");
        // 4.删
        String result02 = (String) valueOperations.getAndDelete("CityInfo:Hangzhou02");
        redisTemplate.delete("CityInfo:Hangzhou02");
        // 5.1设置超时(方式一)
        valueOperations.set("CityInfo:Hangzhou02", "杭州-西湖");
        valueOperations.getAndExpire("CityInfo:Hangzhou02", 5, TimeUnit.MINUTES);
        // 5.2设置超时(方式二)
        valueOperations.set("CityInfo:Hangzhou02", "杭州-西湖");
        redisTemplate.expire("CityInfo:Hangzhou02", 10, TimeUnit.MINUTES);
        // 6.查询Value的字节大小
        Long size =valueOperations.size("CityInfo:Hangzhou02");
        System.out.println("缓存字节大小,size="+size +" bytes");
        log.info("ValueOperations操作结束...");
        return "执行成功";
      }
    }

**3.3测试验证**

使用Postman测试。

请求RUL：http://127.0.0.1:18205/hub-205-redis/hub/example/load/valueOperations

**4.ValueOperations接口**

**4.1接口**

ValueOperations是一个接口，默认实现类是DefaultValueOperations。

接口：org.springframework.data.redis.core.ValueOperations。

实现类：org.springframework.data.redis.core.DefaultValueOperations。

**4.2接口源码**

在源码中，查看接口具体方法，可以快速了解该接口具备功能，以便在生产中能根据实际场景对号入座找到合适方法解决实际问题。

public interface ValueOperations<K, V> {
      void set(K key, V value);
      void set(K key, V value, long timeout, TimeUnit unit);
      default void set(K key, V value, Duration timeout) {
          Assert.notNull(timeout, "Timeout must not be null!");
          if (TimeoutUtils.hasMillis(timeout)) {
              this.set(key, value, timeout.toMillis(), TimeUnit.MILLISECONDS);
          } else {
              this.set(key, value, timeout.getSeconds(), TimeUnit.SECONDS);
          }
      
      }
      @Nullable
      Boolean setIfAbsent(K key, V value);
      @Nullable
      Boolean setIfAbsent(K key, V value, long timeout, TimeUnit unit);
      @Nullable
      default Boolean setIfAbsent(K key, V value, Duration timeout) {
          Assert.notNull(timeout, "Timeout must not be null!");
          return TimeoutUtils.hasMillis(timeout) ? this.setIfAbsent(key, value, timeout.toMillis(), TimeUnit.MILLISECONDS) : this.setIfAbsent(key, value, timeout.getSeconds(), TimeUnit.SECONDS);
      }
      @Nullable
      Boolean setIfPresent(K key, V value);
      @Nullable
      Boolean setIfPresent(K key, V value, long timeout, TimeUnit unit);
      @Nullable
      default Boolean setIfPresent(K key, V value, Duration timeout) {
          Assert.notNull(timeout, "Timeout must not be null!");
          return TimeoutUtils.hasMillis(timeout) ? this.setIfPresent(key, value, timeout.toMillis(), TimeUnit.MILLISECONDS) : this.setIfPresent(key, value, timeout.getSeconds(), TimeUnit.SECONDS);
      }
      void multiSet(Map<? extends K, ? extends V> map);
      @Nullable
      Boolean multiSetIfAbsent(Map<? extends K, ? extends V> map);
      @Nullable
      V get(Object key);
      @Nullable
      V getAndDelete(K key);
      @Nullable
      V getAndExpire(K key, long timeout, TimeUnit unit);
      @Nullable
      V getAndExpire(K key, Duration timeout);
      @Nullable
      V getAndPersist(K key);
      @Nullable
      V getAndSet(K key, V value);
      @Nullable
      List<V> multiGet(Collection<K> keys);
      @Nullable
      Long increment(K key);
      @Nullable
      Long increment(K key, long delta);
      @Nullable
      Double increment(K key, double delta);
      @Nullable
      Long decrement(K key);
      @Nullable
      Long decrement(K key, long delta);
      @Nullable
      Integer append(K key, String value);
      @Nullable
      String get(K key, long start, long end);
      void set(K key, V value, long offset);
      @Nullable
      Long size(K key);
      @Nullable
      Boolean setBit(K key, long offset, boolean value);
      @Nullable
      Boolean getBit(K key, long offset);
      @Nullable
      List<Long> bitField(K key, BitFieldSubCommands subCommands);
      RedisOperations<K, V> getOperations();
    }

以上，感谢。

2023年4月12日