1）遍历电脑的某个目录下所有文件和子目录，2）把txt文件作为列表返回，3）以 key=value形式，即文件名=绝对路径的形式，保存到HashTable或者Map的数据结构中，4）并将该数据结构的实例进行序列化和反序列化，打印序列化前后的结果。-1) traversing the computer all the files to a directory and subdirectories, 2) the txt file as a list of return, 3) to key = value form, or file name = the absolute path of the form, save to the HashTable or the Map data structure, 4) and instances of the data structure serialization and deserialization, print serialized before and after results.