读文件file

File file = new File("D:/temp/grid.txt");
  FileReader fr = new FileReader(file);
  BufferedReader br = new BufferedReader(fr);
  StringBuffer sb = new StringBuffer();
  String lineTxt = br.readLine();
  while (lineTxt != null) {
   sb.append(lineTxt);
   lineTxt = br.readLine();
  }
  this.result = sb.toString();
  return "success";