SpringCache框架应用介绍

2024-04-02 19:04:59 510人浏览安东尼

Python 官方文档：入门教程 => 点击学习

摘要

目录介绍常用注解实际测试介绍 spring Cache是一个框架，实现了基于注解的缓存功能，只需要简单地加一个注解，就能实现缓存功能。 Spring Cache提供了一层抽象，底层可

介绍

spring Cache是一个框架，实现了基于注解的缓存功能，只需要简单地加一个注解，就能实现缓存功能。

Spring Cache提供了一层抽象，底层可以切换不同的cache实现。具体就是通过CacheManager接口来统一不同的缓存技术。

CacheManager是Spring提供的各种缓存技术抽象接口。

针对不同的缓存技术需要实现不同的CacheManager：

CacheManager	描述
EhCacheCacheManager	使用EhCache作为缓存技术
GuavaCacheManager	使用Google的GuavaCache作为缓存技术
RedisCacheManager	使用Redis作为缓存技术

常用注解

注解	说明
@EnableCaching	开启缓存注解功能
@Cacheable	在方法执行前spring先查看缓存中是否有数据，如果有数据，则直接返回缓存数据；若没有数据，调用方法并将方法返回值放到缓存中
@CachePut	将方法的返回值放到缓存中
@CacheEvict	将一条或多条数据从缓存中删除

在Spring Boot项目中，使用缓存技术只需在项目中导入相关缓存技术的依赖包，并在启动类上使用@EnableCaching开启缓存支持即可。

例如，使用Redis作为缓存技术，只需要导入spring-boot-starter-data-redis的Maven坐标即可。

实际测试

使用Spring Cache（默认缓存ConcurrentMapCacheManager）

创建Spring Boot项目，使用mybatisX插件生成对应的mapper、service、实体类等，导入相关依赖，修改配置文件，创建数据库

pom.xml如下：

<?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 http://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>2.4.5</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.itheima</groupId>
    <artifactId>cache_demo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-WEB</artifactId>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.20</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastJSON</artifactId>
            <version>1.2.76</version>
        </dependency>
        <dependency>
            <groupId>commons-lang</groupId>
            <artifactId>commons-lang</artifactId>
            <version>2.6</version>
        </dependency>
        <dependency>
            <groupId>Mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.4.2</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.23</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.4.5</version>
            </plugin>
        </plugins>
    </build>
</project>

application.yml如下：

server:
port: 8080
spring:
application:
#应用的名称，可选
name: cache_demo
datasource:
druid:
driver-class-name: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://localhost:3306/cache_demo?serverTimezone=Asia/Shanghai&useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&useSSL=false&allowPublicKeyRetrieval=true
username: root
passWord: 123456
mybatis-plus:
configuration:
#在映射实体或者属性时，将数据库中表名和字段名中的下划线去掉，按照驼峰命名法映射
map-underscore-to-camel-case: true
log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
global-config:
db-config:
id-type: ASSIGN_ID

数据库SQL如下：


SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user`  (
  `id` bigint(20) NOT NULL,
  `name` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,
  `age` int(11) NULL DEFAULT NULL,
  `address` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Compact;
-- ----------------------------
-- Records of user
-- ----------------------------
INSERT INTO `user` VALUES (1568896554487369729, 'Aiw', 22, '湖北省');
SET FOREIGN_KEY_CHECKS = 1;

在启动类上添加@EnableCaching注解

package com.itheima;
import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;
@Slf4j
@SpringBootApplication
@EnableCaching  // 开启缓存注解功能
public class CacheDemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(CacheDemoApplication.class,args);
        log.info("项目启动成功...");
    }
}

创建UserController

package com.itheima.controller;
import com.itheima.entity.User;
import com.itheima.service.UserService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.CachePut;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.web.bind.annotation.*;
import java.util.List;
import java.util.Objects;
@RestController
@RequestMapping("/user")
@Slf4j
public class UserController {
    @Autowired
    private CacheManager cacheManager;
    @Autowired
    private UserService userService;
    
    @CachePut(value = "userCache", key = "#user.id")
    @PostMapping
    public User save(User user) {
        userService.save(user);
        return user;
    }
    
    @CacheEvict(value = "userCache", key = "#p0")
    //@CacheEvict(value = "userCache",key = "#root.args[0]")
    //@CacheEvict(value = "userCache",key = "#id")
    @DeleteMapping("/{id}")
    public void delete(@PathVariable Long id) {
        userService.removeById(id);
    }
    //@CacheEvict(value = "userCache",key = "#p0.id")
    //@CacheEvict(value = "userCache",key = "#user.id")
    //@CacheEvict(value = "userCache",key = "#root.args[0].id")
    @CacheEvict(value = "userCache", key = "#result.id")
    @PutMapping
    public User update(User user) {
        userService.updateById(user);
        return user;
    }
    
    @Cacheable(value = "userCache", key = "#id", unless = "#result == null")
    @GetMapping("/{id}")
    public User getById(@PathVariable Long id) {
        return userService.getById(id);
    }
    @Cacheable(value = "userCache", key = "#user.id + '_' + #user.name")
    @GetMapping("/list")
    public List<User> list(User user) {
        return userService.lambdaQuery()
                .eq(Objects.nonNull(user.getId()), User::getId, user.getId())
                .eq(Objects.nonNull(user.getName()), User::getName, user.getName())
                .list();
    }
}

以上不同写法均等价

使用apiPost进行接口测试

打断点调试，发送请求，可以看到已存入缓存

该缓存底层基于Map实现，默认ConcurrentHashMap基于内存，重启服务会清空缓存数据

使用Spring Cache（redis缓存RedisCacheManager）

导入Maven坐标

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

修改配置文件

server:
port: 8080
spring:
application:
#应用的名称，可选
name: cache_demo
datasource:
druid:
driver-class-name: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://localhost:3306/cache_demo?serverTimezone=Asia/Shanghai&useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&useSSL=false&allowPublicKeyRetrieval=true
username: root
password: 123456
redis:
host: localhost
port: 6379
# password: root@123456
database: 0
cache:
redis:
time-to-live: 1800000 #设置缓存过期时间（单位：秒），可选
mybatis-plus:
configuration:
#在映射实体或者属性时，将数据库中表名和字段名中的下划线去掉，按照驼峰命名法映射
map-underscore-to-camel-case: true
log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
global-config:
db-config:
id-type: ASSIGN_ID