创建一个新文件，然后将其在classes子目录下保存为NumberValidator . php，其内容如清单17所示。

Create a new file and save it in the classes subdirectory as NumberValidator.php. Its contents are in Listing 17.

youdao

创建一个新文件，然后将其在classes子目录下保存为NumberValidator . php，其内容如清单17所示。

Create a new file and save it in the classes subdirectory as NumberValidator.php. Its contents are in Listing 17.

youdao