谷歌guava开源开发包中的LoadingCache系统缓存机制

CacheController:

package com..cache.googleCache;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@Controller
public class CacheController {

    @RequestMapping("/setCache")
    public void setCache(HttpServletRequest request, HttpServletResponse response) throws IOException {

        String id = request.getParameter("id");
        String name = request.getParameter("name");
        LocalCache.setKey(id,name);
        response.getWriter().print(id+"----"+name);
    }

    @RequestMapping("/getCache")
    public void getCache(HttpServletRequest request, HttpServletResponse response) throws IOException {

        String id = request.getParameter("id");
        Object result = LocalCache.getKey(id);
        response.getWriter().print(result.toString());
    }


}

具体方法：

package com..cache.googleCache;

import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;

import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;

public class LocalCache {

    private static LoadingCache<String, Object> localCache = CacheBuilder.newBuilder()
            .initialCapacity(100)
            .maximumSize(10000)
            //指定时间内没有被创建覆盖，则指定时间过后，再次访问时，会去刷新该缓存，在新值没有到来之前，始终返回旧值
            .refreshAfterWrite(12, TimeUnit.HOURS)
            .build(new CacheLoader<String, Object>() {
                @Override
                public String load(String s) {
                    return "null";
                }
            });

    /**
     * @param key   key
     * @param value value
     */
    public static void setKey(String key, Object value) {
        System.out.println("==> Cache.setKey [key:{} value:{}]"+ key+"----"+ value);
        localCache.put(key, value);for (String s:localCache.asMap().keySet()) {
            try {
                System.err.println(s+"+++111::"+localCache.get(s));
            } catch (ExecutionException e) {
                e.printStackTrace();
            }
        }


    }

    /**
     *
     * @param key key
     * @return Object
     */
    public static Object getKey(String key) {
        try {
            Object value = localCache.get(key);
            if ("null".equals(value)) {
                return null;
            }
            return value;
        } catch (Exception e) {
            e.getMessage();
        }
        return null;
    }




}

模拟调用：

public static void main(String[] args) {
        
//         String url = "http://localhost:8080/setCache?id=1&name=li";
         String url = "http://localhost:8080/getCache?id=2";
         String res = getStringData(url, "");
         System.out.println(res);
    }
    
    public static String getStringData(String url,String data) {
        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost(url);
        httpPost.setHeader("Content-Type", "application/x-www-form-urlencoded");
        try {
            httpPost.setEntity(new StringEntity(data));
            HttpResponse response = httpClient.execute(httpPost);
            String Str = EntityUtils
                    .toString(response.getEntity());
            return Str;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }