Java基础之访问文件与目录——列出目录内容（ListDirectoryContents）

控制台程序，列出目录的全部内容并使用过滤器来选择特定的条目。

 import java.nio.file.*;
 import java.io.IOException;

 public class ListDirectoryContents {
     public static void main (String[] args) {
         Path currentPath=Paths.get(System.getProperty("user.dir"));
         currentPath=currentPath.getParent();

         filterDirectoryContents(currentPath,null);

         System.out.println("\nFilter for .txt:");
         filterDirectoryContents(currentPath,"*.txt");

         System.out.println("\nFilter for .j???:");
         filterDirectoryContents(currentPath,"*.j???");
     }

     private static void filterDirectoryContents(Path path,String filter) {
         try(DirectoryStream<Path> paths=filter != null ? Files.newDirectoryStream(path,filter) : Files.newDirectoryStream(path)){
             System.out.println("\n" + path + " directory contains:");
             for(Path p :paths){
                 System.out.println(" " + p.getFileName() + (Files.isDirectory(p) ? " is a directory." : ""));
             }
         }catch (NotDirectoryException e) {
             System.err.println("Path is not a directory." + e);
         }catch(IOException e) {
             System.err.println("I/O error." + e);
         }
     }
 }