Question

我一直在讨论与FilenameFilter相关的问题。我想将我的类的实现FilenameFilter的对象传递给一个方法，该方法以递归方式将文件传递到文件夹树中。没有作为参数传递的FilenameFilter对象的此方法的一个版本工作正常，但是重载版本没有。问题是它不会递归地进入文件夹树，尽管它应该。也许一个可能的问题与 accept（File dir，String name）的参数有关; 方法，有两个参数，我不太确定我是否以及如何将值传递给他们......我将非常感谢任何帮助...... PS。方法 listfilesRecursive（FilenameFilter filter）使用一个参数处理类 MyFile 的对象，因此一个字段路径

public class MyFile {

String path;
public MyFile (String path) {
    this.path = path;
}

List <File> list = new ArrayList<File> ();
List <String> nameList = new ArrayList <String> ();

 public List <File> listFilesRecursive(FilenameFilter fFilter) {

        File f1 = new File(path);

        File [] files = f1.listFiles(fFilter);

        for (File fil : files) {

            if (fil.isFile()) {
            list.add(fil);
            nameList.add(fil.getName());
        } else if (fil.isDirectory()) {
            this.path = fil.toString();
            this.listFilesRecursive(fFilter);

            }
        }
        Collections.sort(nameList);
        return list;
 }

以下是实现FilenameFilter的类：

class MyFilenameFilter implements FilenameFilter {

    String ext;
public MyFilenameFilter (String ext) {
    this.ext = ext;
}
@Override
    public boolean accept(File dir, String name) {
//      System.out.println(name + " <<<<<<<<<<");
        if(name.lastIndexOf('.')>0)
           {
              int lastIndex = name.lastIndexOf('.');
              String str = name.substring(lastIndex);

              if(str.equals(ext))
              {
                 return true;
              }
           }
           return false;
        }

}

最后，FilenameFilter是一个不错的选择，如果我想实现一个方法，通过文件夹选择它们并根据它们的名称对它们进行过滤？

Answer 1

package hasses.magical.xml.formatter;
import static hasses.magical.xml.formatter.UIOut.uiOut;

import java.io.FilenameFilter;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.stream.Stream;

public class FormattingController
{
   private FilenameFilter fileFilter;

   public FormattingController(FormatParam settings)
   {
      super();
      this.settings = settings;
      //File filter  can of course be any old FileNameFilter implementation 
      fileFilter = new MagicFileNameFilter(settings);
   }

   private FormatParam settings;

   public Integer excecute()
   {
      //In this case dir is set from a placeholder but any old string will do
      try (Stream<Path> walk = Files.walk(Paths.get(settings.getDir()))) {
         //forEach can ofcourse be called path->formatFile(path, someOtherCoolParam) if needed 
         walk.filter(path->fileFilter.accept(null, path.toFile().getName())).forEach(this::formatFile);
         
      } catch (IOException e) {
         uiOut("IOException during traverse dir: %s please check this a valid directory",settings.getDir());
         return -99;
      }
      return 0;
   }

   private void formatFile(Path path)
   {
      if(settings.getVerbose()) {
         uiOut("Will attempt to format: %s",path);
      }
      //do formatting or whatever...
   }

}

如何递归使用FilenameFilter

1 个答案: