content: /**
   * Copyright (c) 2005-2012 springside.org.cn
   * <p>
   * Licensed under the Apache License, Version 2.0 (the "License");
   */
  package com.jeespring.common.web;
  
  import java.io.UnsupportedEncodingException;
  import java.util.Enumeration;
  import java.util.Iterator;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.StringTokenizer;
  import java.util.TreeMap;
  
  import javax.servlet.ServletRequest;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  import org.apache.commons.lang3.Validate;
  import org.springframework.web.context.request.RequestContextHolder;
  import org.springframework.web.context.request.ServletRequestAttributes;
  
  import com.google.common.net.HttpHeaders;
  import com.jeespring.common.config.Global;
  import com.jeespring.common.utils.Encodes;
  import com.jeespring.common.utils.StringUtils;
  import com.jeespring.modules.sys.security.SystemAuthorizingRealm.Principal;
  import com.jeespring.modules.sys.utils.UserUtils;
  
  /**
   * Http与Servlet工具类.
   *
   * @author calvin/HuangBingGui
   * @version 2014-8-19
   */
  public class Servlets {
  
      // -- 常用数值定义 --//
      public static final long ONE_YEAR_SECONDS = 60 * 60 * 24 * 365;
  
      // 静态文件后缀
      private static String[] staticFiles;
  
      /**
       * 设置客户端缓存过期时间 的Header.
       */
      public static void setExpiresHeader(HttpServletResponse response, long expiresSeconds) {
          // Http 1.0 header, set a fix expires date.
          response.setDateHeader(HttpHeaders.EXPIRES, System.currentTimeMillis() + expiresSeconds * 1000);
          // Http 1.1 header, set a time after now.
          response.setHeader(HttpHeaders.CACHE_CONTROL, "private, max-age=" + expiresSeconds);
      }
  
      /**
       * 设置禁止客户端缓存的Header.
       */
      public static void setNoCacheHeader(HttpServletResponse response) {
          // Http 1.0 header
          response.setDateHeader(HttpHeaders.EXPIRES, 1L);
          response.addHeader(HttpHeaders.PRAGMA, "no-cache");
          // Http 1.1 header
          response.setHeader(HttpHeaders.CACHE_CONTROL, "no-cache, no-store, max-age=0");
      }
  
      /**
       * 设置LastModified Header.
       */
      public static void setLastModifiedHeader(HttpServletResponse response, long lastModifiedDate) {
          response.setDateHeader(HttpHeaders.LAST_MODIFIED, lastModifiedDate);
      }
  
      /**
       * 设置Etag Header.
       */
      public static void setEtag(HttpServletResponse response, String etag) {
          response.setHeader(HttpHeaders.ETAG, etag);
      }
  
      /**
       * 根据浏览器If-Modified-Since Header, 计算文件是否已被修改.
       * <p>
       * 如果无修改, checkIfModify返回false ,设置304 not modify status.
       *
       * @param lastModified 内容的最后修改时间.
       */
      public static boolean checkIfModifiedSince(HttpServletRequest request, HttpServletResponse response,
                                                 long lastModified) {
          long ifModifiedSince = request.getDateHeader(HttpHeaders.IF_MODIFIED_SINCE);
          if ((ifModifiedSince != -1) && (lastModified < ifModifiedSince + 1000)) {
              response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
              return false;
          }
          return true;
      }
  
      /**
       * 根据浏览器 If-None-Match Header, 计算Etag是否已无效.
       * <p>
       * 如果Etag有效, checkIfNoneMatch返回false, 设置304 not modify status.
       *
       * @param etag 内容的ETag.
       */
      public static boolean checkIfNoneMatchEtag(HttpServletRequest request, HttpServletResponse response, String etag) {
          String headerValue = request.getHeader(HttpHeaders.IF_NONE_MATCH);
          if (headerValue != null) {
              boolean conditionSatisfied = false;
              if (!"*".equals(headerValue)) {
                  StringTokenizer commaTokenizer = new StringTokenizer(headerValue, ",");
  
                  while (!conditionSatisfied && commaTokenizer.hasMoreTokens()) {
                      String currentToken = commaTokenizer.nextToken();
                      if (currentToken.trim().equals(etag)) {
                          conditionSatisfied = true;
                      }
                  }
              } else {
                  conditionSatisfied = true;
              }
  
              if (conditionSatisfied) {
                  response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
                  response.setHeader(HttpHeaders.ETAG, etag);
                  return false;
              }
          }
          return true;
      }
  
      /**
       * 设置让浏览器弹出下载对话框的Header.
       *
       * @param fileName 下载后的文件名.
       */
      public static void setFileDownloadHeader(HttpServletResponse response, String fileName) {
          try {
              // 中文文件名支持
              String encodedfileName = new String(fileName.getBytes(), "ISO8859-1");
              response.setHeader(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + encodedfileName + "\"");
          } catch (UnsupportedEncodingException e) {
              e.getMessage();
          }
      }
  
      /**
       * 取得带相同前缀的Request Parameters, copy from spring WebUtils.
       * <p>
       * 返回的结果的Parameter名已去除前缀.
       */
      @SuppressWarnings("rawtypes")
      public static Map<String, Object> getParametersStartingWith(ServletRequest request, String prefix) {
          Validate.notNull(request, "Request must not be null");
          Enumeration paramNames = request.getParameterNames();
          Map<String, Object> params = new TreeMap<String, Object>();
          String pre = prefix;
          if (pre == null) {
              pre = "";
          }
          while (paramNames != null && paramNames.hasMoreElements()) {
              String paramName = (String) paramNames.nextElement();
              if ("".equals(pre) || paramName.startsWith(pre)) {
                  String unprefixed = paramName.substring(pre.length());
                  String[] values = request.getParameterValues(paramName);
                  if (values == null || values.length == 0) {
                      values = new String[]{};
                      // Do nothing, no values found at all.
                  } else if (values.length > 1) {
                      params.put(unprefixed, values);
                  } else {
                      params.put(unprefixed, values[0]);
                  }
              }
          }
          return params;
      }
  
      /**
       * 组合Parameters生成Query String的Parameter部分,并在paramter name上加上prefix.
       */
      public static String encodeParameterStringWithPrefix(Map<String, Object> params, String prefix) {
          StringBuilder queryStringBuilder = new StringBuilder();
  
          String pre = prefix;
          if (pre == null) {
              pre = "";
          }
          Iterator<Entry<String, Object>> it = params.entrySet().iterator();
          while (it.hasNext()) {
              Entry<String, Object> entry = it.next();
              queryStringBuilder.append(pre).append(entry.getKey()).append("=").append(entry.getValue());
              if (it.hasNext()) {
                  queryStringBuilder.append("&");
              }
          }
          return queryStringBuilder.toString();
      }
  
      /**
       * 客户端对Http Basic验证的 Header进行编码.
       */
      public static String encodeHttpBasic(String userName, String password) {
          String encode = userName + ":" + password;
          return "Basic " + Encodes.encodeBase64(encode.getBytes());
      }
  
      /**
       * 是否是Ajax异步请求
       *
       * @param request
       */
      public static boolean isAjaxRequest(HttpServletRequest request) {
  
          String accept = request.getHeader("accept");
          String xRequestedWith = request.getHeader("X-Requested-With");
          Principal principal = UserUtils.getPrincipal();
  
          // 如果是异步请求或是手机端，则直接返回信息
          return ((accept != null && accept.indexOf("application/json") != -1
                  || (xRequestedWith != null && xRequestedWith.indexOf("XMLHttpRequest") != -1)
                  || (principal != null && principal.isMobileLogin())));
      }
  
      /**
       * 获取当前请求对象
       *
       * @return
       */
      public static HttpServletRequest getRequest() {
          try {
              return ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
          } catch (Exception e) {
              return null;
          }
      }
  
      /**
       * 判断访问URI是否是静态文件请求
       *
       * @throws Exception
       */
      public static boolean isStaticFile(String uri) {
          if (staticFiles == null)
              staticFiles = StringUtils.split(Global.getConfig("web.staticFile"), ",");
          return StringUtils.endsWithAny(uri, staticFiles) && !StringUtils.endsWithAny(uri, ".html")
                  && !StringUtils.endsWithAny(uri, ".jsp") && !StringUtils.endsWithAny(uri, ".java");
      }
  }
  