java读取文件内容为string字符串的方法

/**

  * 读出城市列表文件

  */

  private string readcityfile() {

   file file02 = new file(path_xinfu, "/citylist.json" );

   fileinputstream is = null ;

   stringbuilder stringbuilder = null ;

   try {

    if (file02.length() != 0 ) {

     /**

      * 文件有内容才去读文件

      */

     is = new fileinputstream(file02);

     inputstreamreader streamreader = new inputstreamreader(is);

     bufferedreader reader = new bufferedreader(streamreader);

     string line;

     stringbuilder = new stringbuilder();

     while ((line = reader.readline()) != null ) {

      // stringbuilder.append(line);

      stringbuilder.append(line);

     }

     reader.close();

     is.close();

    } else {

     mloadinglayout.setstatus(loadinglayout.empty);

    }

   } catch (exception e) {

    e.printstacktrace();

   }

   return string.valueof(stringbuilder);

  }