package saleandbuy.freemodule.web.filter; import java.io.IOException; import java.io.PrintWriter; import java.io.StringWriter; import java.util.Arrays; import java.util.HashMap; import java.util.List; import java.util.Map; import javax.servlet.FilterChain; import javax.servlet.ServletException; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpServletResponseWrapper; import com.alibaba.fastjson.JSON; import com.alibaba.fastjson.JSONArray; import com.alibaba.fastjson.JSONObject; public class CacheResp {  private long waitTime=1000*3;  private static Map<String,CacheInfo> cfgMap=new HashMap<String, CacheResp.CacheInfo>();  public static final String QUERY_STRINGS="queryStrings";  public static final String CACHED_TIME="cachedTime";  public static final String CACHE_CONFIG="cacheConfig";  public static void config(String cfgJson) {   JSONObject cfg=JSON.parseObject(cfgJson);   for (Map.Entry<String, Object> entry : cfg.entrySet()) {    String key=entry.getKey();    Map<String, Object> value=(Map<String, Object>) entry.getValue();    List queryStrings= (JSONArray)value.get(QUERY_STRINGS);    Integer cachedTime=(Integer) value.get(CACHED_TIME);    CacheInfo cacheInfo=new CacheInfo(queryStrings,cachedTime);    cfgMap.put(key, cacheInfo);   }  }  public static void cachedDo(HttpServletRequest request, HttpServletResponse response,FilterChain chain) throws IOException, ServletException {   CacheInfo cacheInfo=getCacheInfo(request);   String queryString=request.getQueryString();   //cacheInfo为空则不需要缓存，不为空则需要缓存   if(cacheInfo!=null){    long now=System.currentTimeMillis();    synchronized (CacheResp.class) {     if(now-cacheInfo.lastUpdateTime>cacheInfo.cachedTime){      System.out.println("not use cache:");       ProxyResponse proxyResponse=new ProxyResponse(response);      chain.doFilter(request, proxyResponse);      cacheInfo.cacheMap.put(queryString, proxyResponse.getBuffer());      cacheInfo.lastUpdateTime=now;     }else {      System.out.println("use cache");     }    }    String cacheStr=cacheInfo.cacheMap.get(queryString).toString();    response.getWriter().write(cacheStr);   }else {    chain.doFilter(request, response);   }  }  private static CacheInfo getCacheInfo(HttpServletRequest request){   String key=request.getRequestURI().replace(request.getContextPath(), "");   CacheInfo cacheInfo=cfgMap.get(key);   if(cacheInfo!=null&&     cacheInfo.needCache(request.getQueryString())){    return cacheInfo;   }   return null;  }  public static class CacheInfo{   public List queryStrings=Arrays.asList(new String[]{"list","index"});   public long cachedTime=1000;   public long lastUpdateTime=0;   public Map<String, StringBuffer> cacheMap=new HashMap<String, StringBuffer>();   public CacheInfo(List queryStrings, Integer cachedTime) {    super();    if(cachedTime!=null){     this.cachedTime = cachedTime;    }    this.queryStrings = queryStrings;   }   /**    *    * @param queryStrings request.getQueryString    * @return    */   public boolean needCache(String queryStrings) {    if(queryStrings==null){//queryStrings为空时默认缓存所有的查询     return true;    }    return queryStrings.contains(queryStrings);   }  }  private static class ProxyResponse extends HttpServletResponseWrapper{   private StringWriter sw=new StringWriter(); //  private ByteArrayOutputStream baos=new ByteArrayOutputStream();   public ProxyResponse(HttpServletResponse response) {    super(response);   }   @Override   public PrintWriter getWriter() throws IOException {    return new PrintWriter(sw);   }   public StringBuffer getBuffer() {    return sw.getBuffer();   }  } }