3.13 分布式缓存

pom.xml

@@ -63,6 +63,21 @@
             <artifactId>jsoup</artifactId>
             <version>1.15.3</version>
         </dependency>
+        <!-- Redis -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-redis</artifactId>
+        </dependency>
+        <!-- 本地缓存 Caffeine -->
+        <dependency>
+            <groupId>com.github.ben-manes.caffeine</groupId>
+            <artifactId>caffeine</artifactId>
+            <version>3.1.8</version>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-configuration-processor</artifactId>
+        </dependency>
         <dependency>
             <groupId>com.mysql</groupId>
             <artifactId>mysql-connector-j</artifactId>

src/main/java/edu/whut/smilepicturebackend/controller/PictureController.java

@@ -1,7 +1,10 @@
 package edu.whut.smilepicturebackend.controller;
 
+import cn.hutool.core.util.RandomUtil;
 import cn.hutool.json.JSONUtil;
 import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
+import com.github.benmanes.caffeine.cache.Cache;
+import com.github.benmanes.caffeine.cache.Caffeine;
 import edu.whut.smilepicturebackend.annotation.AuthCheck;
 import edu.whut.smilepicturebackend.common.BaseResponse;
 import edu.whut.smilepicturebackend.common.DeleteRequest;
@@ -21,12 +24,17 @@ import edu.whut.smilepicturebackend.service.UserService;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.beans.BeanUtils;
+import org.springframework.data.redis.core.StringRedisTemplate;
+import org.springframework.data.redis.core.ValueOperations;
+import org.springframework.util.DigestUtils;
 import org.springframework.web.bind.annotation.*;
 import org.springframework.web.multipart.MultipartFile;
 
 import javax.servlet.http.HttpServletRequest;
+import java.time.Duration;
 import java.util.Arrays;
 import java.util.List;
+import java.util.concurrent.TimeUnit;
 
 @Slf4j
 @RestController
@@ -35,6 +43,16 @@ import java.util.List;
 public class PictureController {
     private final UserService userService;
     private final PictureService pictureService;
+    private final StringRedisTemplate stringRedisTemplate;
+
+    /**
+     * 本地缓存
+     */
+    private final Cache<String, String> LOCAL_CACHE = Caffeine.newBuilder()
+            .initialCapacity(1024)
+            .maximumSize(10_000L) // 最大 10000 条
+            .expireAfterWrite(Duration.ofMinutes(5))  // 缓存 5 分钟后移除
+            .build();
 
     /**
      * 上传图片（可重新上传）
@@ -188,6 +206,52 @@ public class PictureController {
         return ResultUtils.success(pictureService.getPictureVOPage(picturePage, request));
     }
 
+    /**
+     * 分页获取图片列表（封装类，有缓存）
+     */
+    @Deprecated
+    @PostMapping("/list/page/vo/cache")
+    public BaseResponse<Page<PictureVO>> listPictureVOByPageWithCache(@RequestBody PictureQueryRequest pictureQueryRequest,
+                                                                      HttpServletRequest request) {
+        long current = pictureQueryRequest.getCurrent();
+        long size = pictureQueryRequest.getPageSize();
+        // 限制爬虫
+        ThrowUtils.throwIf(size > 20, ErrorCode.PARAMS_ERROR);
+        // 普通用户默认只能看到审核通过的数据
+        pictureQueryRequest.setReviewStatus(PictureReviewStatusEnum.PASS.getValue());
+        // 查询缓存，缓存中没有，再查询数据库
+        // 构建缓存的 key,根据查询条件来构建->json
+        String queryCondition = JSONUtil.toJsonStr(pictureQueryRequest);  //json->md5，更轻量化，去除括号，双引号
+        String hashKey = DigestUtils.md5DigestAsHex(queryCondition.getBytes());
+        String cacheKey = String.format("smilepicture:listPictureVOByPage:%s", hashKey);
+//        // 1. 先从本地缓存中查询
+//        String cachedValue = LOCAL_CACHE.getIfPresent(cacheKey);
+//        if (cachedValue != null) {
+//            // 如果缓存命中，返回结果
+//            Page<PictureVO> cachedPage = JSONUtil.toBean(cachedValue, Page.class);
+//            return ResultUtils.success(cachedPage);
+//        }
+        // 2. 本地缓存未命中，查询 Redis 分布式缓存
+        ValueOperations<String, String> opsForValue = stringRedisTemplate.opsForValue();
+        String cachedValue = opsForValue.get(cacheKey);
+        if (cachedValue != null) {
+            Page<PictureVO> cachedPage = JSONUtil.toBean(cachedValue, Page.class);
+            return ResultUtils.success(cachedPage);
+        }
+        // 3. 查询数据库
+        Page<Picture> picturePage = pictureService.page(new Page<>(current, size),
+                pictureService.getQueryWrapper(pictureQueryRequest));
+        Page<PictureVO> pictureVOPage = pictureService.getPictureVOPage(picturePage, request);
+        // 4. 更新缓存
+        // 更新 Redis 缓存
+        String cacheValue = JSONUtil.toJsonStr(pictureVOPage);
+        // 设置缓存的过期时间，5 - 10 分钟过期，防止缓存雪崩!
+        int cacheExpireTime = 300 + RandomUtil.randomInt(0, 300);
+        opsForValue.set(cacheKey, cacheValue, cacheExpireTime, TimeUnit.SECONDS);
+        // 获取封装类
+        return ResultUtils.success(pictureVOPage);
+    }
+
     /**
      * 编辑图片（给用户使用）
      */

src/main/resources/application.yml

@@ -14,6 +14,13 @@ spring:
     url: jdbc:mysql://localhost:3306/smile-picture
     username: root
     password: 123456
+  # Redis 配置
+  redis:
+    database: 1
+    host: 127.0.0.1
+    port: 6379
+    password: 123456
+    timeout: 5000
   servlet:
     multipart:
       max-file-size: 10MB

src/test/java/edu/whut/smilepicturebackend/RedisStringTest.java

@@ -0,0 +1,48 @@
+package edu.whut.smilepicturebackend;
+
+import lombok.RequiredArgsConstructor;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.data.redis.core.RedisTemplate;
+import org.springframework.data.redis.core.StringRedisTemplate;
+import org.springframework.data.redis.core.ValueOperations;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+@SpringBootTest
+public class RedisStringTest {
+    @Autowired
+    private StringRedisTemplate stringRedisTemplate;
+
+    @Test
+    public void testRedisStringOperations() {
+        // 获取操作对象
+        ValueOperations<String, String> valueOps = stringRedisTemplate.opsForValue();
+
+        // Key 和 Value
+        String key = "testKey";
+        String value = "testValue";
+
+        // 1. 测试新增或更新操作
+        valueOps.set(key, value);
+        String storedValue = valueOps.get(key);
+        assertEquals(value, storedValue, "存储的值与预期不一致");
+
+        // 2. 测试修改操作
+        String updatedValue = "updatedValue";
+        valueOps.set(key, updatedValue);
+        storedValue = valueOps.get(key);
+        assertEquals(updatedValue, storedValue, "更新后的值与预期不一致");
+
+        // 3. 测试查询操作
+        storedValue = valueOps.get(key);
+        assertNotNull(storedValue, "查询的值为空");
+        assertEquals(updatedValue, storedValue, "查询的值与预期不一致");
+
+//        // 4. 测试删除操作
+//        redisTemplate.delete(key);
+//        storedValue = valueOps.get(key);
+//        assertNull(storedValue, "删除后的值不为空");
+    }
+}