Spring内置缓存cache

Spring内置缓存cache

cache介绍

1. cache缓存是spring自带的内置缓存，可以减少系统开销，提高系统效率。
2. cache内置缓存无需网络，数据存放在java内存里。一般做为二级缓存用，缓存地区、热点等数据，数据不会经常修改。如需缓存大量数据，可用Redis缓存

使用cache缓存 提供案例

1. 引入相关依赖

        
        
            org.springframework.boot
            spring-boot-starter-cache
        
        
        
            com.github.ben-manes.caffeine
            caffeine
            2.7.0
        

2. 创建本地caffeine缓存配置CaffeineConfig工具类

import com.github.benmanes.caffeine.cache.Caffeine;
import org.springframework.cache.CacheManager;
import org.springframework.cache.caffeine.CaffeineCache;
import org.springframework.cache.support.SimpleCacheManager;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.time.Duration;
import java.util.ArrayList;
/**
 * 本地caffeine缓存配置
 * @author LiZan
 * @version 1.0
 * @date 2023/2/10 9:54
 */
@Configuration
public class CaffeineConfig  {



    public enum CacheEnum {
        /**
         * @date 16:34 2020/10/27
         * 第一个cache
         **/
        FIRST_CACHE(300, 20000, 300),
        /**
         * @date 16:35 2020/10/27
         * 第二个cache
         **/
        SECOND_CACHE(60, 10000, 200);

        private int second;
        private long maxSize;
        private int initSize;

        CacheEnum(int second, long maxSize, int initSize) {
            this.second = second;
            this.maxSize = maxSize;
            this.initSize = initSize;
        }

    }

    @Bean("caffeineCacheManager")
    public CacheManager cacheManager() {
        SimpleCacheManager cacheManager = new SimpleCacheManager();
        ArrayList caffeineCaches = new ArrayList<>();
        for (CacheEnum cacheEnum : CacheEnum.values()) {
            caffeineCaches.add(new CaffeineCache(cacheEnum.name(),
                    Caffeine.newBuilder().expireAfterWrite(Duration.ofSeconds(cacheEnum.second))
                            .initialCapacity(cacheEnum.initSize)
                            .maximumSize(cacheEnum.maxSize).build()));
        }
        cacheManager.setCaches(caffeineCaches);
        return cacheManager;
    }

}

3. 创建CaffeineUtils工具类,用于增删改查

import org.springframework.boot.CommandLineRunner;
import org.springframework.cache.Cache;
import org.springframework.cache.CacheManager;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;


/**
 * Caffeine缓存工具类
 * @author LiZan
 * @version 1.0
 * @date 2023/2/10 10:41
 */
@Component
public class CaffeineUtils implements CommandLineRunner {

    @Resource(name = "caffeineCacheManager")
    CacheManager cacheManager;

    Cache cache1;
    Cache cache2;

    @Override
    public void run(String... args) throws Exception {
        cache1 = cacheManager.getCache("FIRST_CACHE");
        cache2 = cacheManager.getCache("SECOND_CACHE");
    }

    /**
     * 添加或更新缓存
     *
     * @param key
     * @param value
     */
    public void putAndUpdateCache(String key, Object value) {
        cache1.put(key, value);
    }


    /**
     * 获取对象缓存
     *
     * @param key
     * @return
     */
    public  T getObjCacheByKey(String key, Class t) {

        return cache1.get(key,t);
    }

    /**
     * 根据key删除缓存
     *
     * @param key
     */
    public void removeCacheByKey(String key) {
        // 从缓存中删除
        cache1.evict(key);
    }
}

4. 测试cache缓存，内有redis缓存，如果不用可删除redis相关代码

import com.alibaba.fastjson.JSONObject;
import com.zhengqing.demo.modules.system.entity.User;
import com.zhengqing.demo.utils.CaffeineUtils;
import com.zhengqing.demo.utils.RedisUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;


/**
 * @author LiZan
 * @version 1.0
 * @date 2023/1/4 17:12
 */
@Component
public class UserService  {

    @Autowired
    private RedisUtil redisUtil;

    @Resource
    private CaffeineUtils caffeineUtils;



    public void setUser(User user) {
        System.out.println("缓存信息"+user.toString());
        caffeineUtils.putAndUpdateCache("123",user);
        String s = JSONObject.toJSONString(user);
        System.out.println(s);
        redisUtil.set("123",s);
    }


    public User getUser(String id) {
	    // 一级缓存从redis拿数据
        if(redisUtil.hasKey(id)){
            System.out.println("进去redis缓存");
            String s = redisUtil.get(id);
            User user = JSONObject.parseObject(s,User.class);
            user.setIntro("123123");
            return user;
        }
        // 从cache 拿user缓存
        User user = caffeineUtils.getObjCacheByKey(id, User.class);
        // cache缓存没有，从数据库查
        if(null == user){
            System.out.println("双重缓存失效，进入数据库查询");
            User user1 = createUser();
            //保存cache缓存里
            setUser(user1);
            return user1;
        }
        
        return user;
    }
    
    private User createUser(){
        User zhangsan = User.builder().id(123L).name("ZHANGSAN").age(123).build();
        return zhangsan;
    }


    /**
     * 使用@CachePut注解的方法，一定要有返回值，该注解声明的方法缓存的是方法的返回结果。
     * it always causes the
     * method to be invoked and its result to be stored in the associated cache
     **/
    //@CachePut(key = "#user.getId()", value = "SECOND_CACHE", cacheManager = "caffeineCacheManager")
    //public User setUser(User user) {
    //    System.out.println("已经存储进缓存了");
    //    return user;
    //}

    public void deleteUser(String id) {
        System.out.println("缓存删除了");
        redisUtil.delete(id);
        caffeineUtils.removeCacheByKey(id);
    }

    //@Cacheable(key = "#id", value = "SECOND_CACHE", cacheManager = "caffeineCacheManager")
    //public User getUser(Integer id) {
    //    System.out.println("从数据库取值");
    //    //模拟数据库中的数据
    //    return null;
    //}

import com.zhengqing.demo.lizan.service.UserService;
import com.zhengqing.demo.modules.common.dto.output.ApiResult;
import com.zhengqing.demo.modules.system.entity.User;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;


/**
 * @author LiZan
 * @version 1.0
 * @date 2023/2/10 10:51
 */
@RestController
@RequestMapping("/user")
public class UserController {

    @Autowired
    private UserService userService;

    @GetMapping(value = "/getUser", produces = "application/json;charset=utf-8")
    @ApiOperation(value = "获取用户对象", httpMethod = "GET", response = ApiResult.class)
    public ApiResult getUser() {
        return ApiResult.ok(userService.getUser("123"));
    }

    @GetMapping(value = "/setUser", produces = "application/json;charset=utf-8")
    @ApiOperation(value = "缓存User数据", httpMethod = "GET", response = ApiResult.class)
    public ApiResult setUser() {
        userService.setUser(User.builder().id(123L).name("ZHANGSAN").age(123).build());
        return ApiResult.ok();
    }

    @GetMapping(value = "/delUser", produces = "application/json;charset=utf-8")
    @ApiOperation(value = "删除缓存", httpMethod = "GET", response = ApiResult.class)
    public ApiResult deleteUser() {
        userService.deleteUser("123");
        return ApiResult.ok();
    }

}

6. 执行IP:端口/setUser,getUser,delUser测试结果如下