Spring Boot @Cacheable 方法緩存失效

Spring Boot @Cacheable 方法緩存失效

• 新建了Spring Boot項目，加入了spring-boot-starter-cache依賴的pom.xml：

  <?xml version="1.0" encoding="UTF-8"?>
  <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
      <modelVersion>4.0.0</modelVersion>
      <parent>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-parent</artifactId>
          <version>2.1.8.RELEASE</version>
          <relativePath/> <!-- lookup parent from repository -->
      </parent>
      <groupId>wen</groupId>
      <artifactId>cachesession</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      <name>cachesession</name>
      <description>Demo project for Spring Boot</description>
  
      <properties>
          <java.version>1.8</java.version>
      </properties>
  
      <dependencies>
          <dependency>
              <groupId>org.springframework.boot</groupId>
              <artifactId>spring-boot-starter</artifactId>
          </dependency>
  
          <dependency>
              <groupId>org.springframework.boot</groupId>
              <artifactId>spring-boot-starter-test</artifactId>
              <scope>test</scope>
          </dependency>
  
          <dependency>
              <groupId>org.springframework.boot</groupId>
              <artifactId>spring-boot-starter-data-redis</artifactId>
          </dependency>
  
          <dependency>
              <groupId>org.springframework.boot</groupId>
              <artifactId>spring-boot-starter-web</artifactId>
          </dependency>
  
          <dependency>
              <groupId>org.springframework.boot</groupId>
              <artifactId>spring-boot-starter-cache</artifactId>
          </dependency>
      </dependencies>
  
      <build>
          <plugins>
              <plugin>
                  <groupId>org.springframework.boot</groupId>
                  <artifactId>spring-boot-maven-plugin</artifactId>
              </plugin>
          </plugins>
      </build>
  
  </project>
  
  

• 建立控制類

  package wen.cachesession.controller;
  
  import org.springframework.cache.annotation.Cacheable;
  import org.springframework.web.bind.annotation.RequestMapping;
  import org.springframework.web.bind.annotation.RestController;
  
  @RestController
  public class RedisController {
  
      @RequestMapping("/hello")
      @Cacheable(value = "helloCache")
      public String hello(String name) {
          System.out.println("無緩存");
          return "hello " + name;
      }
  
  }
  
  

• 訪問瀏覽器輸入 http://localhost:8080/hello?name=Stephanie, 刷新幾次之後控制檯輸出“無緩存”， 並不是理想的效果，說明每次服務器都重新加載
  
  

• 解決方案：① 在啓動類增加註解 @EnableCaching， ② 控制類類名處聲明：@CacheConfig(cacheNames = “helloCache”)， 在具體方法上增加@Cacheable

• 啓動類：

  package wen.cachesession;
  
  import org.springframework.boot.SpringApplication;
  import org.springframework.boot.autoconfigure.SpringBootApplication;
  import org.springframework.cache.annotation.EnableCaching;
  
  @SpringBootApplication
  @EnableCaching
  public class CachesessionApplication {
  
      public static void main(String[] args) {
          SpringApplication.run(CachesessionApplication.class, args);
      }
  
  }
  

• 控制類：

  package wen.cachesession.controller;
  
  import org.springframework.cache.annotation.CacheConfig;
  import org.springframework.cache.annotation.Cacheable;
  import org.springframework.web.bind.annotation.RequestMapping;
  import org.springframework.web.bind.annotation.RestController;
  
  @RestController
  @CacheConfig(cacheNames = "helloCache")
  public class RedisController {
  
      @RequestMapping("/hello")
      @Cacheable
      public String hello(String name) {
          System.out.println("無緩存");
          return "hello " + name;
      }
  
  }
  

• 重啓程序刷新之後：網頁顯示不變，但是網頁多次刷新之後控制檯也只輸出一次“無緩存”， 說明調用了緩存