/**

      * 根据元数据和目标ascii位数截取字符串，失败返回-1

      * @param sourceStr    元数据字符串

      * @param endIndex    截取到第几位

      * @return 结果字符串

      */

     public static String indexOf(String sourceStr,int endIndex){

         int length = ;

         StringBuilder result = new StringBuilder();

         List<String> resultList = new ArrayList<String>();

         for(int i = ; i < sourceStr.length(); i++){

             int ascii = Character.codePointAt(sourceStr,i);

             if(ascii >=  && ascii <=){

                 length++;

                 resultList.add(String.valueOf(ascii));

             }else{

                 length+=;

                 resultList.add(String.valueOf(ascii));

             }

             if(length>){

                 if((length==sourceStr.length() && length <= endIndex) || length == endIndex || length == endIndex-){

                     for (String string : resultList) {

                         result.append(asciiToString(string));

                     }

                     return result.toString();

                 }

             }

         }

         //return String.valueOf("-1");

         /**

          * 根据业务要求，如果传进来的参数为空值的时候默认返回空字符串

          */

         return "";

     }

     /**

      * 将ascii码转换为utf-8

      * @param value ascii编码 多个以,号分割

      * @return 结果字符串

      */

     public static String asciiToString(String value) {

         StringBuffer sbu = new StringBuffer();

         String[] chars = value.split(",");

         for (int i = ; i < chars.length; i++) {

             sbu.append((char) Integer.parseInt(chars[i]));

         }

         return sbu.toString();

     }