springboot实现内存缓存

题记：实现缓存大部分可以使用redis实现，简单、便捷，redis在针对应用部署多服务器是很好的，但如果针对单一服务器，内存缓存更好。

1、创建CacheLoader.java

import java.util.Iterator;

import java.util.Map;

/**

 * Created by Tisa on 2018/5/9.

 * 将数据库表记录加载到jvm

 */

public class CacheLoader<V,T> {

    /**

     * 将数据库中的记录加载到jvm缓存，使用Map存储

     *

     * @param from 从数据库load出的记录

     * @param to

     */

    public void loadCache(Map<V, T> from, Map<V, T> to) {

        if (!from.isEmpty()) {

            Iterator<V> iterator = to.keySet().iterator();

            while (iterator.hasNext()) {

                V key = iterator.next();

                if (to.containsKey(key)) {

                    to.remove(key);

                }

            }

            to.putAll(from);

        } else {

            to.clear();

        }

    }
}

2、在springboot启动项目时加载进内存，创建ProvinceAppkeyAndSecretCache.java

import com.entity.ProvinceAppkeyAndAppsecret;

import com.entity.ProvinceInfo;

import com.mapper.ProvinceAppkeyAndSecretMapper;

import com.mapper.ProvinceInfoMapper;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;

import java.util.*;

import java.util.concurrent.ConcurrentHashMap;

/**

 * @author:yangwj

 */

@Component

public class ProvinceAppkeyAndSecretCache {

    private static final Map<String, ProvinceAppkeyAndAppsecret> provinceAppkeyAndSecretCache = new ConcurrentHashMap<>();

    @Autowired

    private ProvinceAppkeyAndSecretMapper provinceAppkeyAndSecretMapper;

    @PostConstruct

    public void init() {

        Map<String, ProvinceAppkeyAndAppsecret> provinceAppkeyAndSecretMap = loadProvinceInfo();

        CacheLoader<String, ProvinceAppkeyAndAppsecret> loader = new CacheLoader<String, ProvinceAppkeyAndAppsecret>();

        loader.loadCache(provinceAppkeyAndSecretMap, provinceAppkeyAndSecretCache);

    }

    private Map<String, ProvinceAppkeyAndAppsecret> loadProvinceInfo() {

        Map<String, ProvinceAppkeyAndAppsecret> map = new HashMap<>();

        List<ProvinceAppkeyAndAppsecret> list = provinceAppkeyAndSecretMapper.selectAll();

        if (list == null) {

            return Collections.emptyMap();

        }

        Iterator<ProvinceAppkeyAndAppsecret> iterator = list.iterator();

        while (iterator.hasNext()) {

            ProvinceAppkeyAndAppsecret next = iterator.next();

            map.put(next.getAppkey(), next);

        }

        return map;

    }

    public ProvinceAppkeyAndAppsecret get(String appkey) {

        return provinceAppkeyAndSecretCache.get(appkey);

    }

}

3、在controller中调用

@RestController

@RequestMapping("Cache")

public class CacheController extends BaseOrderController {

        private static final Logger LOGGER = LoggerFactory.getLogger(com.controller.CacheController.class);

        @Autowired

        private ProvinceAppkeyAndSecretCache provinceAppkeyAndSecretCache;

        @RequestMapping("/cache")

        public String orderRelationUpdateNotify(HttpServletRequest request) {

            String appKey = request.getParameter("appKey");

            //从内存中获取

            ProvinceAppkeyAndAppsecret provinceAppkeyAndAppsecret =provinceAppkeyAndSecretCache.get(appKey);

        }
}

巴特西

springboot实现内存缓存

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