将 File.listFiles 与 FileNameExtensionFilter 一起使用 [英] Using File.listFiles with FileNameExtensionFilter

问题描述

我想获取目录中具有特定扩展名的文件列表.在 API (Java 6) 中，我看到一个方法 File.listFiles(FileFilter) 可以做到这一点.

I would like to get a list of files with a specific extension in a directory. In the API (Java 6), I see a method File.listFiles(FileFilter) which would do this.

因为我需要一个特定的扩展，所以我创建了一个 FileNameExtensionFilter.但是，当我使用 listFiles 时出现编译错误.我认为由于 FileNameExtensionFilter 实现了 FileFilter，我应该能够做到这一点.代码如下:

Since I need a specific extension, I created a FileNameExtensionFilter. However I get a compilation error when I use listFiles with this. I assumed that since FileNameExtensionFilter implements FileFilter, I should be able to do this. Code follows:

FileNameExtensionFilter filter = new FileNameExtensionFilter("text only","txt");
String dir  = "/users/blah/dirname";
File f[] = (new File(dir)).listFiles(filter);

最后一行显示编译错误:

The last line shows a compilation error:

File 类型中的方法 listFiles(FileNameFilter) 不适用于 FileNameExtensionFilter 类型的参数

method listFiles(FileNameFilter) in type File is not applicable for arguments of type FileNameExtensionFilter

我正在尝试使用 listFiles(FileFilter)，而不是 listFiles(FileNameFilter).为什么编译器不能识别?

I am trying to use listFiles(FileFilter), not listFiles(FileNameFilter). Why does the compiler not recognize this?

如果我编写自己的扩展过滤器来扩展 FileFilter，这会起作用.我宁愿使用 FileNameExtensionFilter 而不是自己编写.我做错了什么?

This works if I write my own extension filter extending FileFilter. I would rather use FileNameExtensionFilter than write my own. What am I doing wrong?

推荐答案

FileNameExtensionFilter 类用于 Swing 用于 <代码>JFileChooser.

尝试使用 FilenameFilter 代替.例如:

Try using a FilenameFilter instead. For example:

File dir = new File("/users/blah/dirname");
File[] files = dir.listFiles(new FilenameFilter() {
    public boolean accept(File dir, String name) {
        return name.toLowerCase().endsWith(".txt");
    }
});

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