public class ContextLJ {
	
	private static final Integer JD = 0;
	
	  /**
	   * 上鎖 使用redis 為分布式項(xiàng)目 加鎖
	   * @param sign
	   * @param tiD
	   * @return
	   * @throws Exception
	   */
	  public static boolean lock(String sign, String tiD) {
	    synchronized (JD) { // 加鎖
	    	Cache<String> cache = CacheManager.getCommonCache(sign);
	    	if(cache == null || StringUtils.isBlank(cache.getValue())) {
	    		CacheManager.putCommonCacheInfo(sign, tiD, 10000);
	    		return true;
			}
	    	return false;
	    }
	 }
	 
	  /**
	   * 鎖驗(yàn)證
	   * @param sign
	   * @param tiD
	   * @return
	   */
	  public static boolean checklock(String sign, String tiD){
		  Cache<String> cache = CacheManager.getCommonCache(sign);
		  String uTid = StringUtils.replace(cache.getValue(), "\"", "");
		  return tiD.equals(uTid);
	  }
	 
	  /**
	   * 去掉鎖
	   * @param sign
	   * @param tiD
	   */
	  public static void clent (String sign, String tiD){
		    if (checklock(sign, tiD)) {
		    	CacheManager.clearOnly(sign);
		    }
	  }
	 
	  /**
	   * 獲取摘要
	   * @param request
	   */
	  public static String getSign(ServletRequest request){
	    // 此工具是將 request中的請(qǐng)求內(nèi)容 拼裝成 key=value&key=value2 的形式 源碼在線面
	    String sign = null;
	    try {
	    	Map<String, String> map =  getRequstMap((HttpServletRequest) request);
	    	// 生成摘要
	    	sign = buildRequest(map);
	    } catch (Exception e) {
	    	e.printStackTrace();
	    }
	    return sign;
	  }
	  
	  public static Map<String, String> getRequstMap(HttpServletRequest req) throws Exception{
 		    Map<String,String> params = new HashMap<String,String>();
 		    params.put("uri", req.getRequestURI());
		    Map<String, String[]> requestParams = req.getParameterMap();
		    for (Iterator<String> iter = requestParams.keySet().iterator(); iter.hasNext();) {
		      String name = (String) iter.next();
		      String[] values = (String[]) requestParams.get(name);
		      String valueStr = "";
		      for (int i = 0; i < values.length; i++) {
		        valueStr = (i == values.length - 1) ? valueStr + values[i] : valueStr + values[i] + ",";
		      }
		      params.put(name, valueStr);
		    }
		    return params;
	}
	  
	 private static String buildRequest(Map<String, String> map) {
		 List<String> signList = new ArrayList<>();
		 for(Entry<String, String> entry : map.entrySet()) {
			 signList.add(entry.getKey() + "=" + entry.getValue());
		 }
		 String sign = StringUtils.join(signList, "&");
		 return DigestUtils.md5Hex(sign);
	}
	
}

/**
 * 過(guò)濾頻繁請(qǐng)求
 */
@Slf4j
@Component
public class MyFilter implements Filter{
	
	@Override
	public void init(FilterConfig filterConfig) throws ServletException {
		
	}

	@Override
	public void doFilter(ServletRequest request, ServletResponse myResp, FilterChain chain) throws IOException, ServletException {
		HttpServletRequest req = (HttpServletRequest) request;
		Boolean isDict = StringUtils.contains(req.getRequestURI(), "/dict/getDatas");
		Boolean isFile = StringUtils.contains(req.getRequestURI(), "/files/file");
		if(isDict || isFile) {
			chain.doFilter(request, myResp); // 查詢數(shù)據(jù)字典或者文件，直接放行
			return;
		}
		String sign = "sign_" + ContextLJ.getSign(request); // 生成摘要
	    String tiD = RandomUtils.randomCode(3) + "_" + Thread.currentThread().getId(); // 當(dāng)前線程的身份
	    try { 
	    	if (!ContextLJ.lock(sign, tiD)) {
	    		Map<String,String> map = ContextLJ.getRequstMap((HttpServletRequest)request);
	    		log.warn("放棄相同并發(fā)請(qǐng)求【" + sign+ "】【" + tiD+"】"+JSON.toJSONString(map));
	    		frequentlyError(myResp);
	    		return;
	    	}
	    	if (!ContextLJ.checklock(sign, tiD)) {
	    		Map<String,String> map = ContextLJ.getRequstMap((HttpServletRequest)request);
		    	  log.warn("加鎖驗(yàn)證失敗 【" + sign+ "】【" + tiD+"】"+JSON.toJSONString(map));
		    	  frequentlyError(myResp);
		    	  return;
	    	}
	    	chain.doFilter(request, myResp); // 放行
	    } catch (Exception e) { // 捕獲到異常 進(jìn)行異常過(guò)濾
		      log.error("", e);
		      myResp.getWriter().write(JSON.toJSONString(ApiRs.asError("服務(wù)器繁忙，請(qǐng)重試")));
	    } finally {
	    	ContextLJ.clent(sign, tiD);
	    }
	}

	@Override
	public void destroy() {
		
	}
	
	/**
	 * 頻繁請(qǐng)求
	 */
	private void frequentlyError(ServletResponse myResp) throws IOException {
	  ((HttpServletResponse) myResp).setHeader("Content-type", "text/html;charset=UTF-8");
	  myResp.getWriter().write(JSON.toJSONString(ApiRs.asError("稍安勿躁，不要頻繁請(qǐng)求")));
	}

}