Print Catalog Tree

Question

I need to print a directory tree (e.g. tree command), for example:

. +---A | +---IMAGES | +---BACKUP +---ADOKS | +---ROZDZIAL_2 | +---ROZDZIAL_3 | +---ROZDZIAL_4 +---AMSC2005 | +---AMSC2004 +---FCCS2005 | +---source | +---TMP +---LODZ2004 +---ZAKOPANE2004 +---DYDAKTYKA | +---DYDAKTYKA_ISI | | +---COLLS | | | +---Q1 | | | +---Q2 | | | +---RAZEM | | | +---RYSUNKI_COLL1 | | | +---RYSUNKI_COLL2 | | +---IMAGES | | +---src | | +---WYKLAD5 | +---DYDAKTYKA_PRG | +---images | +---POMOC +---DYDAKTYKA_KST | +---images | +---src +---DYDAKTYKA_WPR +---images +---src 

I tried with the following code:

 private static void getInto(String p, int n) { File path = new File(p); File[] list = path.listFiles(); for (int i = 0; i < list.length; i++) { if (list[i].isDirectorhowny()) { for (int j = 0; j < n; j++) if (WHAT HERE?) System.out.print("| "); else System.out.print(" "); System.out.println("+--" + list[i].getName().toString()); getInto(list[i].getPath(), n + 1); } } } 

I tried several versions, but it still does not work. How to do it? What condition should be included in If? I know this is pretty simple, but I can't do it.

Answer 1

Here is how I did it.

The code

 import java.io.File; public class FileAssert { /** * Pretty print the directory tree and its file names. * * @param folder * must be a folder. * @return */ public static String printDirectoryTree(File folder) { if (!folder.isDirectory()) { throw new IllegalArgumentException("folder is not a Directory"); } int indent = 0; StringBuilder sb = new StringBuilder(); printDirectoryTree(folder, indent, sb); return sb.toString(); } private static void printDirectoryTree(File folder, int indent, StringBuilder sb) { if (!folder.isDirectory()) { throw new IllegalArgumentException("folder is not a Directory"); } sb.append(getIndentString(indent)); sb.append("+--"); sb.append(folder.getName()); sb.append("/"); sb.append("\n"); for (File file : folder.listFiles()) { if (file.isDirectory()) { printDirectoryTree(file, indent + 1, sb); } else { printFile(file, indent + 1, sb); } } } private static void printFile(File file, int indent, StringBuilder sb) { sb.append(getIndentString(indent)); sb.append("+--"); sb.append(file.getName()); sb.append("\n"); } private static String getIndentString(int indent) { StringBuilder sb = new StringBuilder(); for (int i = 0; i < indent; i++) { sb.append("| "); } return sb.toString(); } } 

Result

 +--folder1/ | +--a.txt | +--folder2/ | | +--b1.txt | | +--b2.txt | | +--b3.txt | | +--folder3/ | +--folder4/ 

Unittest

 import static org.junit.Assert.*; import java.io.File; import org.junit.Before; import org.junit.Rule; import org.junit.Test; import org.junit.rules.TemporaryFolder; import org.junit.runner.RunWith; import org.junit.runners.JUnit4; @RunWith(JUnit4.class) public class FileAssertTest { @Rule public TemporaryFolder temporaryFolder = new TemporaryFolder(); private File folder1; @Before public void setUp() { folder1 = temporaryFolder.newFolder("folder1"); } @Test public void testPrintDirectoryTreeWhenFolderIsEmpty() { // Invoke String actual = FileAssert.printDirectoryTree(folder1); // Verify assertEquals("+--folder1/\n", actual); } private static final String EXPECTED_FCOF = "" + "+--folder1/\n" + "| +--a.txt\n"; @Test public void testPrintDirectoryTreeWhenFolderContainsOneFile() throws Exception { // Setup File aFile = new File(folder1, "a.txt"); assertTrue(aFile.createNewFile()); // Invoke String actual = FileAssert.printDirectoryTree(folder1); // Verify assertEquals(EXPECTED_FCOF, actual); } private static final String EXPECTED_COMPLEX = "+--folder1/\n" + "| +--a.txt\n" + "| +--folder2/\n" + "| | +--b1.txt\n" + "| | +--b2.txt\n" + "| | +--b3.txt\n" + "| | +--folder3/\n" + "| +--folder4/\n"; @Test public void testPrintDirectoryTreeComplex() throws Exception { // Setup File aFile = new File(folder1, "a.txt"); assertTrue(aFile.createNewFile()); File folder2 = new File(folder1, "folder2"); assertTrue(folder2.mkdir()); File b1File = new File(folder2, "b1.txt"); assertTrue(b1File.createNewFile()); File b2File = new File(folder2, "b2.txt"); assertTrue(b2File.createNewFile()); File folder3 = new File(folder2, "folder3"); assertTrue(folder3.mkdir()); File b3File = new File(folder2, "b3.txt"); assertTrue(b3File.createNewFile()); File folder4 = new File(folder1, "folder4"); assertTrue(folder4.mkdir()); // Invoke String actual = FileAssert.printDirectoryTree(folder1); // Verify assertEquals(EXPECTED_COMPLEX, actual); } } 

file directory printing pretty-printing

Answer 2

This is my decision:

(The TreeNode class TreeNode copied from there .)

 public static String renderDirectoryTree(TreeNode<FileInformation> tree) { List<StringBuilder> lines = renderDirectoryTreeLines(tree); String newline = System.getProperty("line.separator"); StringBuilder sb = new StringBuilder(lines.size() * 20); for (StringBuilder line : lines) { sb.append(line); sb.append(newline); } return sb.toString(); } public static List<StringBuilder> renderDirectoryTreeLines(TreeNode<FileInformation> tree) { List<StringBuilder> result = new LinkedList<>(); result.add(new StringBuilder().append(tree.getData().getPath().getFileName())); Iterator<TreeNode<FileInformation>> iterator = tree.getChildren().iterator(); while (iterator.hasNext()) { List<StringBuilder> subtree = renderDirectoryTreeLines(iterator.next()); if (iterator.hasNext()) { addSubtree(result, subtree); } else { addLastSubtree(result, subtree); } } return result; } private static void addSubtree(List<StringBuilder> result, List<StringBuilder> subtree) { Iterator<StringBuilder> iterator = subtree.iterator(); //subtree generated by renderDirectoryTreeLines has at least one line which is tree.getData() result.add(iterator.next().insert(0, "├── ")); while (iterator.hasNext()) { result.add(iterator.next().insert(0, "│ ")); } } private static void addLastSubtree(List<StringBuilder> result, List<StringBuilder> subtree) { Iterator<StringBuilder> iterator = subtree.iterator(); //subtree generated by renderDirectoryTreeLines has at least one line which is tree.getData() result.add(iterator.next().insert(0, "└── ")); while (iterator.hasNext()) { result.add(iterator.next().insert(0, " ")); } } 

with this output:

 DirectoryCatalog ├── .git │ ├── COMMIT_EDITMSG │ ├── config │ ├── description │ ├── HEAD │ ├── hooks │ │ ├── applypatch-msg.sample │ │ ├── commit-msg.sample │ │ ├── post-commit.sample │ │ ├── post-receive.sample │ │ ├── post-update.sample │ │ ├── pre-applypatch.sample │ │ ├── pre-commit.sample │ │ ├── pre-push.sample │ │ ├── pre-rebase.sample │ │ ├── prepare-commit-msg.sample │ │ └── update.sample │ ├── index │ ├── info │ │ └── exclude │ ├── logs │ │ ├── HEAD │ │ └── refs │ │ ├── heads │ │ │ └── master │ │ └── remotes │ │ └── origin │ │ └── master │ ├── objects │ │ ├── 0b │ │ │ └── b3fb0a15268c9770220938b1048305429527c7 │ │ ├── 0d │ │ │ └── e508f20f1cb44ff543cec54ea93a71e5e40d1d │ │ ├── 10 │ │ │ └── 9c753f3aab08f167f8409e6c9abec27cad6548 │ │ ├── 15 │ │ │ └── 7602556ebd120e656ae8dcd00cb361bfb3ef79 │ │ ├── 16 │ │ │ └── 952a5d1f5f3d15199f3e85b3d895a81990024e │ │ ├── 1c │ │ │ └── 5b36cd4d41b9b7d0df46d4184512098186c904 │ │ ├── 20 │ │ │ └── ae5cc82ebbb85f9161d8fd9783905e4cbee72c │ │ ├── 21 │ │ │ └── e42add0fb2205a75ff621dbeb6d76455816b79 │ │ ├── 23 │ │ │ └── af4eaa4007ca941e562406b7b329c6ba4b395e │ │ ├── 28 │ │ │ └── 6caf4b7be3ac85a476f3782220fe167a040971 │ │ ├── 2b │ │ │ └── f6743fb97162e999fb6429510bb8a52114bc31 │ │ ├── 35 │ │ │ └── acd4ab6acb599d4e3244be2a8dc3a0161bcb3c │ │ ├── 46 │ │ │ └── 1ef7c4db86e0466bb8f1f81dc25f12e3598db6 │ │ ├── 47 │ │ │ └── 4ce7f18330e5295ab1ef2eea66505235819e22 │ │ ├── 4b │ │ │ └── 825dc642cb6eb9a060e54bf8d69288fbee4904 │ │ ├── 4e │ │ │ └── 4e047c077c7825a845deebda7f97832cee847b │ │ ├── 4f │ │ │ └── 20b118269d71535e469966fdb5fe8a78ae6c9a │ │ ├── 51 │ │ │ └── 677b295b4cd9931354dd52fb6050015d524fea │ │ ├── 52 │ │ │ └── 9c34997d8262bd207037f0373703d68d4e1a4e │ │ ├── 5b │ │ │ └── 928f45816cc51609861f0930251accbe7de7f9 │ │ ├── 5d │ │ │ └── 7cdbe029c6eff99c72d09b0a81347b605e77d7 │ │ ├── 61 │ │ │ └── 2b9d86f6ac365ede894e13a6273fd13833f44f │ │ ├── 67 │ │ │ └── 2209cb240eac0303d6e3b6c7eb04242d661fad │ │ ├── 6b │ │ │ ├── c84e19913908f16141677b9d66abdb620350a0 │ │ │ └── d278b63be854ccd3c02b9038ee43366021b1a1 │ │ ├── 6c │ │ │ └── 9d10e91679988caaee6759d48daf336f28a9a3 │ │ ├── 70 │ │ │ └── 4284c78f1c664c1348af5a784cca55c51fd66a │ │ ├── 72 │ │ │ └── 1ab5fe4e4226930668048d97331103a92751be │ │ ├── 78 │ │ │ └── 64a41eaf50f32ae8d2cab1acd200c405215c1a │ │ ├── 82 │ │ │ └── 36f772feca12b3e301eea50774458a7e77c7fb │ │ ├── 83 │ │ │ └── bc1e2a1f3187f28d63d7fa334744810d80c20d │ │ ├── 87 │ │ │ └── 3ce97f624e9a1ae4a1bbf41218d50dc3503d6f │ │ ├── 8a │ │ │ └── 0b282aa6885fb573c106b3551f7275c5f17e8e │ │ ├── 91 │ │ │ └── a7e269e19dfc62e27137a0b57ef3e430cee4fd │ │ ├── 94 │ │ │ ├── 065a39b0dd7ce05604b96aff84d984493553e2 │ │ │ └── 5cbc994fb2d251437e71edf3a6eb289c5836ec │ │ ├── 95 │ │ │ └── f481326b62c9adff2a0dad47480e279adb518f │ │ ├── 9e │ │ │ └── 1f7de67de38e67479cb8e38ad92d6354838393 │ │ ├── a1 │ │ │ └── e385dff1fb08b7a45ea52af43b22d240f0adab │ │ ├── a7 │ │ │ └── 8934a5a81d95a85b9c97a3e1c1429186feb83d │ │ ├── ab │ │ │ └── 855c3379bdb3e4a22605de58f3438148d6ffe7 │ │ ├── b7 │ │ │ └── 64eafa2ba4e7f8f52a4e96da61b3d77f262d16 │ │ ├── bd │ │ │ └── 9374662b409bb364779212874e7cf611541c38 │ │ ├── c1 │ │ │ └── f858c163f9c8cb89a145a60e87c9e35c97fb93 │ │ ├── c3 │ │ │ └── 35d07a1078656646ca6e980b468b938106d357 │ │ ├── c5 │ │ │ └── ac562c59d6a0430fa0ccd1fa6318fa5d48604f │ │ ├── c8 │ │ │ └── f3d9284a65afbff6640da7970664ee2134c85b │ │ ├── c9 │ │ │ └── 7a8bdb9088d370da7e88784a7a093b971aa23a │ │ ├── cc │ │ │ └── a6a5141b614b5e351c7e5b6b677ef09a931786 │ │ ├── d1 │ │ │ └── 76229a9e1d0172f84d060904d171be51f9d0f6 │ │ ├── d3 │ │ │ ├── 2f0a1ba59a0c52d3acc62de1d624fb68423ee3 │ │ │ └── b9dfcb3216a2feab03b1ae96280e3c1c963953 │ │ ├── e0 │ │ │ └── 6d2081865a766a8668acc12878f98b27fc9ea0 │ │ ├── e5 │ │ │ └── 3106578cd8adcd085c5c63c05fc49d5a5a3dbb │ │ ├── info │ │ └── pack │ └── refs │ ├── heads │ │ └── master │ ├── remotes │ │ └── origin │ │ └── master │ └── tags ├── .gitattributes ├── .gitignore ├── .gradle │ └── 2.2.1 │ └── taskArtifacts │ ├── cache.properties │ ├── cache.properties.lock │ ├── fileHashes.bin │ ├── fileSnapshots.bin │ ├── outputFileStates.bin │ └── taskArtifacts.bin ├── .idea │ ├── .name │ ├── compiler.xml │ ├── copyright │ │ └── profiles_settings.xml │ ├── encodings.xml │ ├── gradle.xml │ ├── libraries │ │ ├── Gradle__commons_io_commons_io_2_4.xml │ │ ├── Gradle__junit_junit_4_11.xml │ │ └── Gradle__org_hamcrest_hamcrest_core_1_3.xml │ ├── misc.xml │ ├── modules.xml │ ├── scopes │ │ └── scope_settings.xml │ ├── uiDesigner.xml │ ├── vcs.xml │ └── workspace.xml ├── app │ ├── app.iml │ ├── build │ │ ├── classes │ │ │ └── main │ │ │ └── gq │ │ │ └── baijie │ │ │ └── catalog │ │ │ ├── controllor │ │ │ │ ├── FilesScanner$MyFileVisitor.class │ │ │ │ └── FilesScanner.class │ │ │ ├── entity │ │ │ │ └── FileInformation.class │ │ │ ├── Main.class │ │ │ └── util │ │ │ ├── FileAssert.class │ │ │ ├── Hash.class │ │ │ ├── HEX.class │ │ │ ├── Printer$1.class │ │ │ ├── Printer$DirectoryTreeRender.class │ │ │ ├── Printer.class │ │ │ └── TreeNode.class │ │ ├── dependency-cache │ │ ├── resources │ │ │ └── main │ │ └── tmp │ │ └── compileJava │ ├── build.gradle │ └── src │ ├── main │ │ └── java │ │ └── gq │ │ └── baijie │ │ └── catalog │ │ ├── controllor │ │ │ └── FilesScanner.java │ │ ├── entity │ │ │ └── FileInformation.java │ │ ├── Main.java │ │ └── util │ │ ├── FileAssert.java │ │ ├── Hash.java │ │ ├── HEX.java │ │ ├── Printer.java │ │ └── TreeNode.java │ └── test │ └── java ├── DirectoryCatalog.iml ├── gradle │ └── wrapper │ ├── gradle-wrapper.jar │ └── gradle-wrapper.properties ├── gradlew ├── gradlew.bat ├── LICENSE ├── README.md ├── settings.gradle └── temp ├── 150110161006.txt ├── 150110173453.txt ├── 150110175353.txt ├── 150111111311.txt ├── 150111112500.txt ├── 150111113411.txt ├── 150111155619.txt ├── 150111161958.txt ├── 150111162230.txt ├── 150111162632.txt ├── 150111163225.txt ├── 150111163330.txt ├── 150111164526.txt ├── 150111205412.txt ├── 150111210322.txt ├── 150111210506.txt ├── 150111210927.txt ├── 150111211249.txt ├── 150111211321.txt ├── 150111220750.txt ├── 150111220822.txt ├── 150111221437.txt ├── 150111221842.txt ├── 150111222437.txt ├── 150111234344.txt ├── 150111234433.txt └── 150112000034.txt 

Answer 3

You need to print "|" whenever you do not process the last record at the appropriate level, but one of the records to the last. You must know this for each level separately, so you can add a bitmask or string (say) as an additional argument to "getInto".

Answer 4

 import java.io.File; public class MainEntry { public static void main(String[] args) { walkin(new File("/home/user")); //Replace this with a suitable directory } /** * Recursive function to descend into the directory tree and find all the files @param dir A file object defining the top directory **/ public static void walkin(File dir) { File listFile[] = dir.listFiles(); if (listFile != null) { for (int i=0; i<listFile.length; i++) { if (listFile[i].isDirectory()) { System.out.println("|\t\t"); walkin(listFile[i]); } else { System.out.println("+---"+listFile[i].getName().toString()); } } } } 

}

Will work fine .. The logic is correct

Answer 5

Think of it this way:

 procedure printOutput(file, depth): print "| " depth times; print "+---" + file name; print new line if(file is a directory): for(each file inside file, say innerFile): call printOutput(innerFile, depth + 1); 

Hope this helps.

Answer 6

  import java.io.File; public class Tree { public static void main(String[] args) throws Exception { File folder = new File((args.length >= 1 && args[0].length() > 0) ? args[0] : "."); if (!folder.isDirectory()) { throw new IllegalArgumentException("Invalid directory: " + folder.getName()); } int level = 0; System.out.println(renderFolder(folder, level, new StringBuilder(), false)); } private static StringBuilder renderFolder(File folder, int level, StringBuilder sb, boolean isLast) { indent(sb, level, isLast).append("[D] ").append(folder.getName()).append("\n"); File[] objects = folder.listFiles(); for (int i = 0; i < objects.length; i++) { boolean last = ((i + 1) == objects.length); if (objects[i].isDirectory()) { renderFolder(objects[i], level + 1, sb, last); } else { renderFile(objects[i], level + 1, sb, last); } } return sb; } private static StringBuilder renderFile(File file, int level, StringBuilder sb, boolean isLast) { return indent(sb, level, isLast).append("--- ").append(file.getName()).append("\n"); } private static StringBuilder indent(StringBuilder sb, int level, boolean isLast) { for (int i = 1; i < level; i++) { sb.append("| "); } if (level > 0) { sb.append(isLast ? "`-" : "|-"); } return sb; } } [D] . |-[D] classes | |-[D] .data | | `---- Play.cdi_javac | |---- ArrayListTest$Pair.class | |---- ArrayListTest.class | |---- ArrayTest.class | |-[D] fruit | | |---- Apple.class | | `---- GrannySmith.class | |---- IfTest.class | |-[D] interview | | |---- Q1.class | | |---- Q2.class | | |---- Q3.class | | |---- Q3Sub.class | | |---- Q9Sub.class | | `---- Q9Super.class | |---- IntOverflowTest.class | |---- LinkedMapTest.class | |-[D] log | | `---- Logger.class | |---- log.properties | |---- StringCaseTest.class | |-[D] test | | |-[D] cache | | | |-[D] test1 | | | | |---- Cache.class | | | | |---- CacheEntry.class | | | | `---- RevisedCacheTest.class | | | |-[D] test2 | | | | |---- Cache.class | | | | |---- Log.class | | | | `---- RevisedCacheTest.class | | | `-[D] test3 | | | | |---- ConcurrentCache.class | | | | `---- ConcurrentCacheTest.class | | |---- Test.class | | `---- Test2.class | |---- Test.class | |---- Test2.class | `---- ZipTest.class `---- Play.jpr 

Answer 7

This is my decision:

 import java.io.File; public class MostrarArbol { public static void main(String args[]) { File carpeta = new File(args[0]); // File carpeta = new File("."); if (!carpeta.exists()) { System.out.println(args[0] + " NO existe."); return; } imprimeArbol(carpeta, ""); } public static void imprimeArbol(File carpeta, String tabulador) { File contenido[] = carpeta.listFiles(); if (contenido != null) { for (int i = 0; i < contenido.length; i++) if (contenido[i].isDirectory()) { System.out.println(tabulador + "|-" + contenido[i].getName()); imprimeArbol(contenido[i], tabulador + "| "); } else { System.out.println(tabulador + "+-" + contenido[i].getName().toString()); } } } } 

Answer 8

This is my code. It works.

 package DIRS; import java.io.File; public class LISTDIR { public static void main(String[] args) { String path = System.getProperty("user.dir")+File.separator; File file[] = new File(path).listFiles(); for(int i = 0 ; i < file.length ; i++) { if(file[i].isDirectory()) { System.out.println("->"+file[i].getName()); new LISTDIR().listfiles(file[i],"--"); } else { System.out.println("-> "+file[i].getName()); } } } public void listfiles(File f,String sprtr) { File file[] = f.listFiles(); for(int i = 0 ; i < file.length ; i++) { if(file[i].isDirectory()) { System.out.println(sprtr+file[i].getName()); new LISTDIR().listfiles(file[i],"--"+sprtr); } else { System.out.println(sprtr+file[i].getName()); } } } } 

Answer 9

I tested the solution with the most bursts written by @ tan70, however it caused a null pointer exception when printing my home directory. I did some research and found that listFiles () can return zero.

open file [] listFiles ()

Returns an array of abstract paths denoting files in the directory indicated by this abstract path.

If this abstract path does not indicate a directory, then this method returns zero . Otherwise, an array of File objects is returned, one for each file or directory in the directory.

 /** * Pretty print the directory tree and its file names. * * @param path * @return */ public static String printDirectoryTree(String path) { File folder = new File(path); if (!folder.isDirectory()) { throw new IllegalArgumentException("folder is not a Directory"); } int indent = 0; StringBuilder sb = new StringBuilder(); printDirectoryTree(folder, indent, sb); return sb.toString(); } private static void printDirectoryTree(File folder, int indent, StringBuilder sb) { if (folder != null && folder.isDirectory() && folder.listFiles() != null) { sb.append(getIndentString(indent)); sb.append("+--"); sb.append(folder.getName()); sb.append("/"); sb.append("\n"); for (File file : folder.listFiles()) { if (file.isDirectory()) { printDirectoryTree(file, indent + 1, sb); } else { printFile(file, indent + 1, sb); } } } } private static void printFile(File file, int indent, StringBuilder sb) { sb.append(getIndentString(indent)); sb.append("+--"); if (file != null) { sb.append(file.getName()); } else { sb.append("null file name"); } sb.append("\n"); } private static String getIndentString(int indent) { StringBuilder sb = new StringBuilder(); for (int i = 0; i < indent; i++) { sb.append("| "); } return sb.toString(); } 

Answer 10

Link and change the functions of tree structures from this :

 import org.apache.commons.io.FileUtils; import java.io.File; import java.io.FileWriter; import java.io.IOException; import java.util.Iterator; import java.util.LinkedList; import java.util.List; public class TreeNode<T> implements Iterable<TreeNode<T>> { public T data; public TreeNode<T> parent; public List<TreeNode<T>> children; public boolean isRoot() { return parent == null; } public boolean isLeaf() { return children.size() == 0; } private List<TreeNode<T>> elementsIndex; public TreeNode(T data) { this.data = data; this.children = new LinkedList<TreeNode<T>>(); this.elementsIndex = new LinkedList<TreeNode<T>>(); this.elementsIndex.add(this); } public TreeNode<T> addChild(T child) { TreeNode<T> childNode = new TreeNode<T>(child); childNode.parent = this; this.children.add(childNode); this.registerChildForSearch(childNode); return childNode; } public int getLevel() { if (this.isRoot()) return 0; else return parent.getLevel() + 1; } private void registerChildForSearch(TreeNode<T> node) { elementsIndex.add(node); if (parent != null) parent.registerChildForSearch(node); } public TreeNode<T> findTreeNode(Comparable<T> cmp) { for (TreeNode<T> element : this.elementsIndex) { T elData = element.data; if (cmp.compareTo(elData) == 0) return element; } return null; } @Override public String toString() { return data != null ? data.toString() : "[data null]"; } @Override public Iterator<TreeNode<T>> iterator() { TreeNodeIter<T> iter = new TreeNodeIter<T>(this); return iter; } public static TreeNode<File> createDirTree(File folder) { if (!folder.isDirectory()) { throw new IllegalArgumentException("folder is not a Directory"); } TreeNode<File> DirRoot = new TreeNode<File>(folder); for (File file : folder.listFiles()) { if (file.isDirectory()) { appendDirTree(file, DirRoot); } else { appendFile(file, DirRoot); } } return DirRoot; } public static void appendDirTree(File folder, TreeNode<File> DirRoot) { DirRoot.addChild(folder); for (File file : folder.listFiles()) { if (file.isDirectory()) { appendDirTree(file, DirRoot.children.get(DirRoot.children.size() - 1)); } else { appendFile(file, DirRoot.children.get(DirRoot.children.size() - 1)); } } } public static void appendFile(File file, TreeNode<File> filenode) { filenode.addChild(file); } public static String renderDirectoryTree(TreeNode<File> tree) { List<StringBuilder> lines = renderDirectoryTreeLines(tree); String newline = System.getProperty("line.separator"); StringBuilder sb = new StringBuilder(lines.size() * 20); for (StringBuilder line : lines) { sb.append(line); sb.append(newline); } return sb.toString(); } public static List<StringBuilder> renderDirectoryTreeLines(TreeNode<File> tree) { List<StringBuilder> result = new LinkedList<>(); result.add(new StringBuilder().append(tree.data.getName())); Iterator<TreeNode<File>> iterator = tree.children.iterator(); while (iterator.hasNext()) { List<StringBuilder> subtree = renderDirectoryTreeLines(iterator.next()); if (iterator.hasNext()) { addSubtree(result, subtree); } else { addLastSubtree(result, subtree); } } return result; } private static void addSubtree(List<StringBuilder> result, List<StringBuilder> subtree) { Iterator<StringBuilder> iterator = subtree.iterator(); //subtree generated by renderDirectoryTreeLines has at least one line which is tree.getData() result.add(iterator.next().insert(0, "├── ")); while (iterator.hasNext()) { result.add(iterator.next().insert(0, "│ ")); } } private static void addLastSubtree(List<StringBuilder> result, List<StringBuilder> subtree) { Iterator<StringBuilder> iterator = subtree.iterator(); //subtree generated by renderDirectoryTreeLines has at least one line which is tree.getData() result.add(iterator.next().insert(0, "└── ")); while (iterator.hasNext()) { result.add(iterator.next().insert(0, " ")); } } public static void main(String[] args) { File file = new File("./"); TreeNode<File> DirTree = createDirTree(file); String result = renderDirectoryTree(DirTree); System.out.println(result); try { File newTextFile = new File("./DirectoryTree.txt"); FileWriter fw = new FileWriter(newTextFile); fw.write(result); fw.close(); } catch (IOException iox) { iox.printStackTrace(); } } } 

with this conclusion:

 . ├── .DS_Store ├── .idea │ ├── compiler.xml │ ├── dictionaries │ │ └── yankai01.xml │ ├── encodings.xml │ ├── misc.xml │ └── workspace.xml ├── data_exploring.iml ├── pom.xml ├── src │ ├── .DS_Store │ ├── main │ │ ├── .DS_Store │ │ ├── java │ │ │ ├── FileAssert.java │ │ │ ├── HttpUtils.java │ │ │ ├── QuerySaveToCsv.java │ │ │ ├── SampleData.java │ │ │ ├── SampleIterating.java │ │ │ ├── SampleSearching.java │ │ │ ├── TreeNode.java │ │ │ └── TreeNodeIter.java │ │ └── resources │ └── test │ └── java └── target ├── classes │ ├── FileAssert.class │ ├── HttpUtils.class │ ├── QuerySaveToCsv.class │ ├── SampleData.class │ ├── SampleIterating.class │ ├── SampleSearching$1.class │ ├── SampleSearching.class │ ├── TreeNode.class │ ├── TreeNodeIter$ProcessStages.class │ └── TreeNodeIter.class └── generated-sources └── annotations