public static Object getField(Object o, String fieldName) throws SecurityException, NoSuchFieldException, IllegalArgumentException, IllegalAccessException{
		Field field;
		try{
			field = o.getClass().getField(fieldName);
		}catch(NoSuchFieldException e){
			try{
				field = o.getClass().getDeclaredField(fieldName);
			}
			catch(NoSuchFieldException e1){
				field = o.getClass().getSuperclass().getField(fieldName);
			}
		}

		if(field.isAccessible() == false){
			//privateメンバにもアクセス可能になる
			field.setAccessible(true);
		}
		Object value = field.get(o);
		message = "オブジェクト"+ o + "のフィールド"+ fieldName + ": "+ value + "\r\n";
		display.append(message);
		return value;
	}