Filenames and Pathnames

将每天学的东西贴上来: 
1. Constructing a Filename Path 

String path = File.separator + "a" + File.separator + "b";
System.out.println("-----------> "+path);

2.Creating a File 

 File file = new File("filename.txt");
 // Create file if it does not exist
boolean success = file.createNewFile();

3.Getting the Size of a File 

File file = new File("filename.txt");
// Get the number of bytes in the file
long length = file.length();
System.out.println("length------------->"+length);

4.Renaming a File or Directory 

// File (or directory) with old name
        File file = new File("filename.txt");
        // File (or directory) with new name
        File file2 = new File("file.txt");
        // Rename file (or directory)
        boolean success = file.renameTo(file2);
        if (!success) {
            // File was not successfully renamed
        }