如何通过Java读取文件夹中的所有文件?这与哪个API无关。


当前回答

在Java 7及更高版本中,您可以使用listdir

Path dir = ...;
try (DirectoryStream<Path> stream = Files.newDirectoryStream(dir)) {
    for (Path file: stream) {
        System.out.println(file.getFileName());
    }
} catch (IOException | DirectoryIteratorException x) {
    // IOException can never be thrown by the iteration.
    // In this snippet, it can only be thrown by newDirectoryStream.
    System.err.println(x);
}

您还可以创建一个过滤器,然后将其传递给上面的newDirectoryStream方法

DirectoryStream.Filter<Path> filter = new DirectoryStream.Filter<Path>() {
    public boolean accept(Path file) throws IOException {
        try {
            return (Files.isRegularFile(path));
        } catch (IOException x) {
            // Failed to determine if it's a file.
            System.err.println(x);
            return false;
        }
    }
};

有关其他过滤示例,[参见文档]。(http://docs.oracle.com/javase/tutorial/essential/io/dirs.html#glob)

其他回答

File folder = new File("/Users/you/folder/");
File[] listOfFiles = folder.listFiles();

for (File file : listOfFiles) {
    if (file.isFile()) {
        System.out.println(file.getName());
    }
}
package com;


import java.io.File;

/**
 *
 * @author ?Mukesh
 */
public class ListFiles {

     static File mainFolder = new File("D:\\Movies");

     public static void main(String[] args)
     {
         ListFiles lf = new ListFiles();
         lf.getFiles(lf.mainFolder);

         long fileSize = mainFolder.length();
             System.out.println("mainFolder size in bytes is: " + fileSize);
             System.out.println("File size in KB is : " + (double)fileSize/1024);
             System.out.println("File size in MB is :" + (double)fileSize/(1024*1024));
     }
     public void getFiles(File f){
         File files[];
         if(f.isFile())
             System.out.println(f.getAbsolutePath());
         else{
             files = f.listFiles();
             for (int i = 0; i < files.length; i++) {
                 getFiles(files[i]);
             }
         }
     }
}

java.io.FileFilter的用法很好,见https://stackoverflow.com/a/286001/146745

File fl = new File(dir);
File[] files = fl.listFiles(new FileFilter() {          
    public boolean accept(File file) {
        return file.isFile();
    }
});
public static List<File> files(String dirname) {
    if (dirname == null) {
        return Collections.emptyList();
    }

    File dir = new File(dirname);
    if (!dir.exists()) {
        return Collections.emptyList();
    }

    if (!dir.isDirectory()) {
        return Collections.singletonList(file(dirname));
    }

    return Arrays.stream(Objects.requireNonNull(dir.listFiles()))
        .collect(Collectors.toList());
}
public void listFilesForFolder(final File folder) {
    for (final File fileEntry : folder.listFiles()) {
        if (fileEntry.isDirectory()) {
            listFilesForFolder(fileEntry);
        } else {
            System.out.println(fileEntry.getName());
        }
    }
}

final File folder = new File("/home/you/Desktop");
listFilesForFolder(folder);

文件。walk API可从Java 8获得。

try (Stream<Path> paths = Files.walk(Paths.get("/home/you/Desktop"))) {
    paths
        .filter(Files::isRegularFile)
        .forEach(System.out::println);
} 

这个例子使用了API指南中推荐的try-with-resources模式。它确保在任何情况下流都将被关闭。