如何在java中创建FileFilter？

问题描述

在标题中如何过滤到.txt文件？

like in title how to make filter to .txt files?

我写了这样的东西，但它有错误：（

i wrote something like this but it has error :(

 private void jMenuItem1ActionPerformed(java.awt.event.ActionEvent evt) {                                           
        JFileChooser chooser = new JFileChooser();
        int retval = chooser.showOpenDialog(null);

        String yourpath = "E:\\Programy Java\\Projekt_SR1\\src\\project_sr1";
        File directory = new File(yourpath);
        String[] myFiles;
        FilenameFilter filter = new FilenameFilter() {
        public boolean accept(File directory, String fileName) {
            return fileName.endsWith(".txt");
        }
        };
        myFiles = directory.list(filter);


        if(retval == JFileChooser.APPROVE_OPTION)
        {
            File myFile = chooser.getSelectedFile();
        }

推荐答案

你会发现一些有用的例子。 也是JFileChooser中使用的FileFilter的一个很好的例子。

Here you will find some working examples. This is also a good example of FileFilter used in JFileChooser.

基础是，你需要覆盖类，并在其accpet方法中编写自定义代码。上例中的accept方法是根据文件类型进行过滤：

The basics are, you need to override FileFilter class and write your custom code in its accpet method. The accept method in above example is doing filtration based on file types:

public boolean accept(File file) {
    if (file.isDirectory()) {
      return true;
    } else {
      String path = file.getAbsolutePath().toLowerCase();
      for (int i = 0, n = extensions.length; i < n; i++) {
        String extension = extensions[i];
        if ((path.endsWith(extension) && (path.charAt(path.length() 
                  - extension.length() - 1)) == '.')) {
          return true;
        }
      }
    }
    return false;
}

或者更简单易用的是，其接受方法使用filename作为参数，因此您无需获取它手动。

Or more simpler to use is FileNameFilter which has accept method with filename as argument, so you don't need to get it manually.

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