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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