今天学到一个新知识:SpringCache,刚开始项目是使用Redis来进行缓存数据,但是当进行数据库操作的时候,通常也需要对Redis缓存的数据进行操作,这就需要写很多的代码量。

然后就了解到了SpringCache,可以通过注解来把数据添加到缓存或者删除缓存中的数据。

SpringCache的使用

  1. springboot项目需要导入web依赖
        <!--springboot项目进行web开发必不可少的依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <scope>compile</scope>
        </dependency>
  1. 在启动类中使用@EnableCaching注解开启缓存
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
public class CacheDemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(CacheDemoApplication.class,args);
        log.info("项目启动成功...");
    }
}
  1. 使用注解进行业务开发
package com.itheima.controller;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
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.ArrayList;
import java.util.List;

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

    @Autowired
    private CacheManager cacheManager;

    @Autowired
    private UserService userService;

    /**
     * CachePut:将方法返回值放入缓存
     * value:缓存的名称,每个缓存名称下面可以有多个key
     * key:缓存的key
     * @param user
     * @return
     */
    @CachePut(value = "userCache",key = "#user.id")
    @PostMapping
    public User save(User user){
        userService.save(user);
        return user;
    }


    /**
     * CacheEvict:清理指定的缓存
     * value:缓存的名称,每个缓存名称下面可以有多个key
     * key:缓存的key
     */
    @CacheEvict(value = "userCache",key = "#id")
//    @CacheEvict(value = "userCache",key = "#p0")    //第一个参数
//    @CacheEvict(value = "userCache",key = "#root.args[0]")  //第一个参数
    @DeleteMapping("/{id}")
    public void delete(@PathVariable Long id){
        userService.removeById(id);
    }


    /**
     *
     * @param user
     * @return
     */
    @CacheEvict(value = "userCache",key = "#user.id")
//    @CacheEvict(value = "userCache",key = "#p0.id")   //获取user中的id
//    @CacheEvict(value = "userCache",key = "#root.args[0].id")  //获取user中的id
//    @CacheEvict(value = "userCache",key = "#result.id")  //获取user中的id
    @PutMapping
    public User update(User user){
        userService.updateById(user);
        return user;
    }

    /**
     * Cacheable:先看缓存中有没有数据,如果有就不再执行sql
     * condition:条件,满足指定条件时才缓存数据
     * unless:满足条件则不缓存
     * @param id
     * @return
     */
//    @Cacheable(value = "userCache",key = "#id",condition = "#result != null ")
    @Cacheable(value = "userCache",key = "#id",unless = "#result == null ")
    @GetMapping("/{id}")
    public User getById(@PathVariable Long id){
        User user = userService.getById(id);
        return user;
    }


    /**
     * Cacheable
     * @param user
     * @return
     */
    @Cacheable(value = "userCache",key = "#user.id + #user.name")
    @GetMapping("/list")
    public List<User> list(User user){
        LambdaQueryWrapper<User> queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper.eq(user.getId() != null,User::getId,user.getId());
        queryWrapper.eq(user.getName() != null,User::getName,user.getName());
        List<User> list = userService.list(queryWrapper);
        return list;
    }
}


12-26 12:19