Concat在Java中的文件中无法正常工作

Question

I have to do a project without the swing library.I have to browse over the files and was trying to do something like this:

fichero = new File(fichero.getAbsolutePath().concat("\\" + str));

where str is the new Directory that you want to access

Hope someone could help me. Thank you

Answer 1

This

fichero = new File(fichero.getAbsolutePath() + "\\" + str);

or

fichero = new File(fichero.getAbsolutePath() + "/" + str);

or

fichero = new File(fichero.getAbsolutePath().concat("/").concat(str);

should work fine.

Answer 2

You may use \\\\ or you may use a / . I suggest you use the latter as it is platform independent.

Also, use the constructor:

File(String parent, String child)  

The docs say:

Creates a new File instance from a parent pathname string and a child pathname string. If parent is null then the new File instance is created as if by invoking the single-argument File constructor on the given child pathname string.

Otherwise the parent pathname string is taken to denote a directory, and the child pathname string is taken to denote either a directory or a file. If the child pathname string is absolute then it is converted into a relative pathname in a system-dependent way. If parent is the empty string then the new File instance is created by converting child into an abstract pathname and resolving the result against a system-dependent default directory. Otherwise each pathname string is converted into an abstract pathname and the child abstract pathname is resolved against the parent.

So, your code should look like:

fichero = new File(fichero.getAbsolutePath(),str);  

NB: You may also use the File constructor that accepts a File and String as an argument, thus eliminating the call to getAbsolutePath()