code: public static Object getObjFromFile(String file, int i) {
  		ObjectInputStream ois = null;
  		Object obj = null;
  		try {
  			FileInputStream fis = new FileInputStream(file);
  			ois = new ObjectInputStream(fis);
  			for (int j = 0; j < i; j++) {
  				obj = ois.readObject();
  			}
  		} catch (Exception e) {
  			e.printStackTrace();
  		} finally {
  			try {
  				ois.close();
  			} catch (IOException e) {
  				e.printStackTrace();
  			}
  		}
  		return obj;
  	}
docs: 返回在文件中指定位置的对象
  
  @param file
  指定的文件
  @param i
  从1开始
  @return