code: public static Map<String, String> paraFilter(Map<String, String> sArray) {
  		Map<String, String> result = new HashMap<String, String>();
  		if (sArray == null || sArray.size() <= 0) {
  			return result;
  		}
  		for (String key : sArray.keySet()) {
  			String value = sArray.get(key);
  			if (value == null || value.equals("") || key.equalsIgnoreCase("sign")
  					|| key.equalsIgnoreCase("sign_type")) {
  				continue;
  			}
  			result.put(key, value);
  		}
  		return result;
  	}
docs: 除去数组中的空值和签名参数
  
  @param sArray
  签名参数组
  @return 去掉空值与签名参数后的新签名参数组