打印输出目录下的所有文件

public static   void printFile(String a)throws IOException
    {
        try {
            
            File file =new File(a);
            
            for (File aa : file.listFiles()) {
                if (aa.isDirectory()){
                    printFile(aa.toString());
//                    System.out.println(aa);
                
                }
                else if(aa.list()==null)
                {
                    System.out.println(aa);
                }
                
                
            }
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }