1.File class overview and construction method
2.File class creation function
File created successfully!
If the file does not exist, create the file and return true.
If the file exists, do not create the file and return false.
If the folder does not exist, create the folder and return true.
If the folder exists, do not create the folder and return false. Return false
to create multi-level directories using mkdirs()
3.File class judgment and acquisition functions
4.File class deletion function
