List files within directory

Issue: BAEL-2447
2019-01-27 11:51:13 +05:30
parent 6a2dc09fb6
commit 9a567f95b4
6 changed files with 114 additions and 0 deletions
@@ -0,0 +1,64 @@
+package com.baeldung.files;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.DirectoryStream;
+import java.nio.file.FileVisitResult;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.SimpleFileVisitor;
+import java.nio.file.attribute.BasicFileAttributes;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class ListFiles {
+    public static final int DEPTH = 1;
+
+    public Set<String> listFilesUsingJavaIO(String dir) {
+        return Stream.of(new File(dir).listFiles())
+            .filter(file -> !file.isDirectory())
+            .map(File::getName)
+            .collect(Collectors.toSet());
+    }
+
+    public Set<String> listFilesUsingFileWalk(String dir, int depth) throws IOException {
+        try (Stream<Path> stream = Files.walk(Paths.get(dir), depth)) {
+            return stream.filter(file -> !Files.isDirectory(file))
+                .map(Path::getFileName)
+                .map(Path::toString)
+                .collect(Collectors.toSet());
+        }
+    }
+
+    public Set<String> listFilesUsingFileWalkAndVisitor(String dir) throws IOException {
+        Set<String> fileList = new HashSet<>();
+        Files.walkFileTree(Paths.get(dir), new SimpleFileVisitor<Path>() {
+            @Override
+            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
+                if (!Files.isDirectory(file)) {
+                    fileList.add(file.getFileName()
+                        .toString());
+                }
+                return FileVisitResult.CONTINUE;
+            }
+        });
+        return fileList;
+    }
+
+    public Set<String> listFilesUsingDirectoryStream(String dir) throws IOException {
+        Set<String> fileList = new HashSet<>();
+        try (DirectoryStream<Path> stream = Files.newDirectoryStream(Paths.get(dir))) {
+            for (Path path : stream) {
+                if (!Files.isDirectory(path)) {
+                    fileList.add(path.getFileName()
+                        .toString());
+                }
+            }
+        }
+        return fileList;
+    }
+
+}