SpringCash

简介

• Spring Cache是一个框架，实现了基于注解的缓存功能
• 底层可以使用EHCache、Caffeine、Redis实现缓存。

注解一般放在Controller的方法上，@CachePut 注解一般有两个参数，第一个时存储的名称，第二个时名称后边的key，使用SpEL动态的计算key。其余的注解也都是这两个参数。在用户端的查询操作需要使用@Cacheable，服务器端的增删改都使用@CacheEvict

引入依赖

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

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

mysql
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>

mybatis
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.2.0</version>
</dependency>

application.yml配置

server:
  port: 8888
spring:
  datasource:
    druid:
      driver-class-name: com.mysql.cj.jdbc.Driver
      url: jdbc:mysql://localhost:3306/test?serverTimezone=Asia/Shanghai&useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&useSSL=false&allowPublicKeyRetrieval=true
      username: root
      password: 123456
  redis:
    host: localhost
    port: 6379
    password: 123456
    database: 1
logging:
  level:
    com:
      itheima:
        mapper: debug
        service: info
        controller: info

常用注解

使用

1. 启动类添加注解

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
-----------------------------------------
添加下面的注解
@EnableCaching
-----------------------------------------
public class CacheDemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(CacheDemoApplication.class,args);
        log.info("项目启动成功...");
    }
}

使用方法上添加注解

package com.itheima.controller;

import com.itheima.entity.User;
import com.itheima.mapper.UserMapper;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.CachePut;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/user")
@Slf4j
public class UserController {

    @Autowired
    private UserMapper userMapper;


    /**
     * 新增方法返回值放入缓存
     */
    @PostMapping
    //参数1，缓存名称，参数2，动态获取方法参数字段
    //最总保存效果是 [参数1::参数2]。例如[userCache::1]
    @CachePut(cacheNames = "userCache", key = "#user.id")
    //也可以这样写，参数2不再是方法参数，而是方法的返回值
    //@CachePut(cacheNames = "userCache",key = "#result.id")
    //也可以这样写，p0代表第一个参数，p1代表第二个参数
    //@CachePut(cacheNames = "userCache", key = "#p0.id")
    public User save(@RequestBody User user) {
        userMapper.insert(user);
        return user;
    }



    //删除  userCache::id
    @CacheEvict(cacheNames = "userCache", key = "#id")
    @DeleteMapping
    public void deleteById(Long id) {
        userMapper.deleteById(id);
    }


    //删除 所有的 userCache::*
    @CacheEvict(cacheNames = "userCache", allEntries = true)
    @DeleteMapping("/delAll")
    public void deleteAll() {
        userMapper.deleteAll();
    }


    //cache生成 userCache::id
    @Cacheable(cacheNames = "userCache", key = "#id")
    @GetMapping
    public User getById(Long id) {
        User user = userMapper.getById(id);
        return user;
    }

}