Question

我有一个目录C:\myDir。

在此目录下，可能有文件夹和各种文件

如何“循环”浏览此目录并构建包含.properties扩展名的所有文件的文件数组？

我想对这些文件进行一些处理，File []的原因是保持动态（因此将来会添加额外的属性文件）

我希望能做到这样的事情：

public static void main (String[] vargs)
{

   // find all .properties files
   //

   //loop through property file and process
   {
      doSomething(myFile[i]);
   }

}

public void doSomething(File myfile) {}

Answer 1

请看FilenameFilter。

final FilenameFilter filter = new FilenameFilter() {
      public boolean accept(final File directory, final String name) {
        return name.endsWith(".properties");
      }
};

Answer 2

您可以使用Apache Commons IO FileUtils类。

FileUtils.listFiles(File directory, String[] extensions, boolean recursive);

希望这有帮助。

Answer 3

使用commons-io FilenameUtils

final File dir = new File("c:\\myDir");
final File[] files = dir.listFiles(new FilenameFilter() {
    @Override
    public boolean accept(final File dir, final String name) {
        return FilenameUtils.isExtension(name, "properties");
    }
});

Answer 4

实现了返回递归到目录的文件的代码。

import java.io.File;
import java.util.ArrayList;
import java.util.List;


public class FileList {
    public static void main(String[] args) {
        File dir = new File("/usr/local/work_apps");

        String filterExt = "properties";

        List<File> fileList = new ArrayList<File>();

        getFileteredFiles(dir,filterExt,fileList);

        for (File file : fileList) {
            System.out.println("FileList.main() "+file.getName());
        }

    }

    /**
     * Get files recursively filtered by file extention.
     * @param dir search directory for.
     * @param filterExt file extention filter.
     * @param fileList List passed to method to be filled with file's.
     */
    public static  void getFileteredFiles(File dir,String filterExt,List<File> fileList){

        if(dir.isDirectory()){
            File[] files = dir.listFiles();
            if(files != null && files.length > 0){
            for (File file : files) {
                if(file.isDirectory()){
                    getFileteredFiles(file, filterExt, fileList);
                }else{
                    if(file.getName().endsWith("."+filterExt)){
                        fileList.add(file);
                    }
                }
            }
            }
        }

    }

}

Answer 5

Apache commons IO有一个很好的类来遍历名为DirectoryWalker的文件系统。如果要以递归方式查找这些属性文件，请将其签出。

例如，下面的代码将以递归方式查找目录下的图像文件，并将其作为List返回。

import com.google.common.collect.Lists;
import java.io.File;
import java.io.IOException;
import java.util.Collection;
import java.util.List;
import org.apache.commons.io.DirectoryWalker;
import org.apache.commons.io.IOCase;
import org.apache.commons.io.filefilter.AndFileFilter;
import org.apache.commons.io.filefilter.DirectoryFileFilter;
import org.apache.commons.io.filefilter.HiddenFileFilter;
import org.apache.commons.io.filefilter.IOFileFilter;
import org.apache.commons.io.filefilter.NotFileFilter;
import org.apache.commons.io.filefilter.OrFileFilter;
import org.apache.commons.io.filefilter.PrefixFileFilter;
import org.apache.commons.io.filefilter.SuffixFileFilter;

class SourceImageFinder extends DirectoryWalker {

    public SourceImageFinder() {
        // visible directories and image files
        super(new AndFileFilter(notHiddenFileFilter(), new OrFileFilter(imageFileFilter(), DirectoryFileFilter.INSTANCE)), -1);
    }

    public List<File> findSourceImages(File directory) {
        List<File> results = Lists.newArrayList();
        try {
            walk(directory, results);
        } catch (IOException ex) {
            throw new RuntimeException("Problem finding images", ex);
        }
        return results;
    }

    @Override
    protected void handleFile(File file, int depth, Collection results) throws IOException {
        results.add(file);
    }

    private static IOFileFilter notHiddenFileFilter() {
        // HiddenFileFilter.HIDDEN doesn't exclude files starting with '.' on Windows but I want to.
        return new NotFileFilter(new OrFileFilter(HiddenFileFilter.HIDDEN, new PrefixFileFilter(".")));
    }

    private static IOFileFilter imageFileFilter() {
        return new SuffixFileFilter(new String[]{"png", "jpg", "jpeg", "gif", "bmp", "tif", "tiff"}, IOCase.INSENSITIVE);
    }
}

Answer 6

这是一个没有外部库的完整答案：

public class FileFinder{

    public static List<File> findFiles(final File baseDir, final String regex){
        final List<File> files = new ArrayList<File>();

        scanFolder(baseDir, Pattern.compile(regex), files);
        return files;
    }

    private static void scanFolder(final File dir,
        final Pattern pattern,
        final List<File> files){

        for(final File candidate : dir.listFiles()){
            if(candidate.isDirectory()){
                scanFolder(candidate, pattern, files);
            } else if(pattern.matcher(candidate.getName()).matches()){
                files.add(candidate);
            }
        }
    }

}

这样称呼：

public static void main(String[] args){
    List<File> filesAsList = FileFinder.findFiles(
                                new File("c:\\my\\dir"), ".*\\.properties");
    File[] filesAsArray = filesAsList.toArray(new File[filesAsList.size()]);
}

如何为给定目录下的所有* .properties创建File []？

6 个答案: