本程序用于获取cad图纸的目录，具体设计思路是，首先从一个文件中获取属性块，并得到其属性文件，最后将其内容读出，从而可以生成一个目录。-Cad drawings of the procedure used to obtain the directory, specific design idea is, first of all to obtain attributes from a file block, and get the properties file, and finally read out its contents, which can generate a directory.