Redis-mysql 缓存实战

本文基于Springboot，mybatis plus，mysql，redis， Jedis模拟redis缓存实现

目录

1. 添加所需maven依赖

2. 设置数据库及数据表

3. 构建实体类

4. 构建工具类实现 redis 数据库连接池，redis 的读取，写入功能

5. Redis 缓存实战

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1. 添加所需maven依赖

        <!--  web开发模块--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><!-- 添加jedis依赖，操作redis--><dependency><groupId>redis.clients</groupId><artifactId>jedis</artifactId><version>3.6.3</version></dependency><!--  mybatis-plus 依赖--><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.4.2</version></dependency><!--  mysql连接驱动--><dependency><groupId>com.mysql</groupId><artifactId>mysql-connector-j</artifactId><scope>runtime</scope></dependency><!--  lombok模块--><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><optional>true</optional></dependency>

2. 设置数据库及数据表

  执行以下 sql 脚本新建表 product 并插入四条数据

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;-- ----------------------------
-- Table structure for product
-- ----------------------------
DROP TABLE IF EXISTS `product`;
CREATE TABLE `product`  (`id` int NOT NULL AUTO_INCREMENT,`name` varchar(40) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL,`price` float NULL DEFAULT NULL,`category` int NULL DEFAULT NULL,PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 5 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci ROW_FORMAT = Dynamic;-- ----------------------------
-- Records of product
-- ----------------------------
INSERT INTO `product` VALUES (1, 'phone', 1899, 10);
INSERT INTO `product` VALUES (2, 'apple', 1899, 20);
INSERT INTO `product` VALUES (3, 'food', 1600, 30);
INSERT INTO `product` VALUES (4, 'rice', 1230, 40);SET FOREIGN_KEY_CHECKS = 1;

3. 构建实体类

  这里使用 lombok 来构建setter，getter，构造方法，toString方法

@Data
@ToString
@AllArgsConstructor
@NoArgsConstructor
@TableName("product")
public class Product {private Integer id;private String name;private Float price;private Integer category;
}

4. 构建工具类实现 redis 数据库连接池，redis 的读取，写入功能

public class JedisUtil {private static JedisPool jedisPool;static{// 配置连接池JedisPoolConfig config = new JedisPoolConfig();config.setMaxTotal(10);  // 设置最大连接数config.setMaxIdle(5);  // 设置最大空闲连接数config.setBlockWhenExhausted(false);  // 连接耗尽时不阻塞// 创建连接池jedisPool = new JedisPool(config,"localhost",6379);}// 从数据池获取 Jedis 连接public static Jedis getJedisPool(){return jedisPool.getResource();}// 存储商品到 redis---key:(product:id)  field:  valuepublic static long saveToRedis(Product product){Jedis jedis = JedisUtil.getJedisPool();HashMap<String,String> hashMap = new HashMap();hashMap.put("name",product.getName());hashMap.put("price",String.valueOf(product.getPrice()));hashMap.put("category",String.valueOf(product.getCategory()));String key = "product:" + product.getId();long flag = jedis.hset(key, hashMap);// 设置过期时间jedis.expire(key,3600L);jedis.close();return flag;}// 从 redis 读取数据public static Product getProductByRedis(int id){Jedis jedis = JedisUtil.getJedisPool();Product product = null;String key = "product:" + id;if(jedis.exists(key)){String name = jedis.hget(key,"name");String price = jedis.hget(key,"price");String category = jedis.hget(key,"category");product = new Product(id,name,Float.parseFloat(price),Integer.parseInt(category));}jedis.close();return product;}
}

5. Redis 缓存实战

  前端请求路径：http://localhost/getProductById?id=2

  后端新建一个 ProductMapper 接口

@Mapper
public interface ProductMapper {@Select("select * from product")List<Product> getProduct();@Select("select * from product where id=#{id}")Product getProductById(int id);
}

  后端新建一个 ProductController 类

@RestController
public class ProductController {@ResourceProductMapper productMapper;@GetMapping("/product")public List<Product> getProduct(){return productMapper.getProduct();}@GetMapping("/getProductById")public Product getProductById(int id){Product product = null;// 1. 查看 redis 缓存中是否有数据product = JedisUtil.getProductByRedis(id);if(product == null){  // redis 中没有该商品// 2.进 mysql 中查询product = productMapper.getProductById(id);if(product==null){ // mysql 中没有System.out.println("mysql 中未查询到该商品");}else { // mysql 中有System.out.println("mysql查询到该商品: "+product);// 3.返回给前端的同时也要将数据写入到 redis 中long flag = JedisUtil.saveToRedis(product);System.out.println("save flag:"+flag);}}else {  // redis 中有该商品System.out.println("redis查询到该商品: " + product);}return product;}
}

  第一次读取数据时是从 mysql 中读取，当该数据写入 redis 后，读取速度明显加快