Java 递归列出目录下的文件以及子目录
2018-07-20 来源:open-open
import java.io.File; import java.io.FilenameFilter; import java.io.FileFilter; /** * ----------------------------------------------------------------------------- * This program demonstrates how to list the file or subdirectories in a * given directory * * @version 1.0 * ----------------------------------------------------------------------------- */ public class ListFilesSubs { /** * Used to list the files / subdirectories in a given directory. * @param dir Directory to start listing from */ private static void doSimpleFileListing(String dirName) { System.out.println(); System.out.println("Simple file listing..."); System.out.println("----------------------"); File dir = new File(dirName); String[] children = dir.list(); printFiles(children, dirName); } /** * Used to list the files / subdirectories in a given directory and also * provide a filter class. * @param dir Directory to start listing from * @param ff A string that can be used to filter out files from the * returned list of files. In this example, the String * values is used to only return those values that start * with the given String. */ private static void doFileFilterListing(String dirName, String ff) { System.out.println("Filter file listing..."); System.out.println("----------------------"); final String fileFilter = ff; File dir = new File(dirName); FilenameFilter filter = null; if (fileFilter != null) { // It is also possible to filter the list of returned files. // This example uses the passed in String value (if any) to only // list those files that start with the given String. filter = new FilenameFilter() { public boolean accept(File dir, String name) { return name.startsWith(fileFilter); } }; } String[] children = dir.list(filter); printFiles(children, dirName); } /** * Used to list the files / subdirectories in a given directory and also * provide a filter class that only lists the directories. * @param dir Directory to start listing from */ private static void doFileFilterDirectoryListing(String dirName) { System.out.println("Filter Directory listing..."); System.out.println("---------------------------"); File dir = new File(dirName); // The list of files can also be retrieved as File objects. In this // case, we are just listing all files in the directory. For the sake // of this example, we will not print them out here. File[] files = (new File(dirName)).listFiles(); // This filter only returns directories FileFilter dirFilter = new FileFilter() { public boolean accept(File dir) { return dir.isDirectory(); } }; files = dir.listFiles(dirFilter); for (int i=0; i<files.length; i++) { System.out.println("[D] : " + files[i]); } System.out.println(); } /** * Utility method to print the list of files to the terminal * @param children A String array of the file names to print out * @param dirName The given directory to start the listing at. */ private static void printFiles(String[] children, String dirName) { if (children == null) { System.out.println("Error with " + dirName); System.out.println("Either directory does not exist or is not a directory"); } else { for (int i=0; i<children.length; i++) { // Get filename of file or directory String filename = children[i]; if ((new File(dirName + File.separatorChar + filename)).isDirectory()) { System.out.print("[D] : "); } else { System.out.print("[F] : "); } System.out.println(dirName + File.separatorChar + filename); } } System.out.println(); } /** * Sole entry point to the class and application. * @param args Array of String arguments. */ public static void main(String[] args) { // Call the simple file listing method doSimpleFileListing("new_dir"); // Now do the file listing but pass in a String to filter the file list if (args.length == 0) { doFileFilterListing("new_dir", null); } else { doFileFilterListing("new_dir", args[0]); } // Now do another example that only prints out the directories doFileFilterDirectoryListing("new_dir"); } }
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