查询Redis缓存数据，没有再去查询MySQL

pom.xml

@@ -35,6 +35,10 @@
             <groupId>org.projectlombok</groupId>
             <artifactId>lombok</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-redis</artifactId>
+        </dependency>
     </dependencies>
 
 </project>

src/main/java/com/mashibing/entity/Air.java

@@ -2,12 +2,14 @@ package com.mashibing.entity;
 
 import lombok.Data;
 
+import java.io.Serializable;
+
 /**
  * @author zjw
  * @description
  */
 @Data
-public class Air {
+public class Air implements Serializable {
 
     private Long id;
 

src/main/java/com/mashibing/service/impl/AirServiceImpl.java

@@ -4,8 +4,12 @@ import com.mashibing.entity.Air;
 import com.mashibing.mapper.AirMapper;
 import com.mashibing.service.AirService;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.redis.core.RedisTemplate;
+import org.springframework.data.redis.core.StringRedisTemplate;
 import org.springframework.stereotype.Service;
 
+import javax.annotation.Resource;
+
 /**
  * @author zjw
  * @description
@@ -13,12 +17,26 @@ import org.springframework.stereotype.Service;
 @Service
 public class AirServiceImpl  implements AirService {
 
-    @Autowired
+    @Resource
     private AirMapper airMapper;
 
+    @Autowired
+    private RedisTemplate redisTemplate;
+
+    private final String AIR_PREFIX = "air:";
+
+
     @Override
     public Air getById(Long id) {
-        Air air = airMapper.findById(id);
+        // 查询Redis缓存之前，先去查询一下JVM中的缓存 ConcurrentHashMap 作为JVM缓存
+
+        // 查询数据库之前，查询Redis中的数据
+        Air air = (Air) redisTemplate.opsForValue().get(AIR_PREFIX + id);
+        if(air == null) {
+            // 查询数据库
+            air = airMapper.findById(id);
+        redisTemplate.opsForValue().set(AIR_PREFIX + id,air);
+    }
         return air;
     }
 }