File类的构造方法

    public static void main(String[] args) throws IOException {
　　　　　// 都是输出C:\a.txt
        File f = new File("C:\\a.txt");
        System.out.println(f);
        
        File f1 = new File("C:\\","a.txt");
        System.out.println(f1);
        
        File f2 = new File(new File("C:\\"),"a.txt");
        System.out.println(f2);
    }