获取java中文件夹中的文件数

Question

我正在制作一个基本的文件浏览器，想知道如何获取任何给定目录中的文件数（对于将文件添加到树和表中的for循环所必需的）

Answer 1

来自javadocs：

• http://download.oracle.com/javase/6/docs/api/java/io/File.html

您可以使用：

new File("/path/to/folder").listFiles().length

Answer 2

new File(<directory path>).listFiles().length

Answer 3

至于java 7：

/**
 * Returns amount of files in the folder
 *
 * @param dir is path to target directory
 *
 * @throws NotDirectoryException if target {@code dir} is not Directory
 * @throws IOException if has some problems on opening DirectoryStream
 */
public static int getFilesCount(Path dir) throws IOException, NotDirectoryException {
    int c = 0;
    if(Files.isDirectory(dir)) {
        try(DirectoryStream<Path> files = Files.newDirectoryStream(dir)) {
            for(Path file : files) {
                if(Files.isRegularFile(file) || Files.isSymbolicLink(file)) {
                    // symbolic link also looks like file
                    c++;
                }
            }
        }
    }
    else
        throw new NotDirectoryException(dir + " is not directory");

    return c;
}