Hi guys I'm trying to find if a specific file is inside the project directory.
File f = new File(System.getProperty("user.dir"));
System.out.println(f);
String archivoLiga="LigaV2";
System.out.println(f.listFiles((dir1, name) -> name.startsWith(archivoLiga) && name.endsWith(".properties")).length == 0);
But this only works if the file is in the "first" level, i want it to find it even if it's inside another folder. Any ideas?
Use Java 8's find() method to recurse subdirectories:
final int MAX_DEPTH = 50; // Max depth of subdirectories to search
Path userDir = Paths.get(System.getProperty("user.dir"));
System.out.println(userDir);
String archivoLiga="LigaV2";
System.out.println(
Files.find(
userDir,
maxDepth,
(path,attr) -> path.getFileName().startsWith(archivoLiga)
&& path.getFileName().endsWith(".properties"))
.findAny()
.isPresent());
Try recursively looking inside subfolders :-
public boolean checkForFile(String dirname,String prefix,String ext){
File dir = new File(dirname);
//System.out.println(dir);
for(File f : dir.listFiles()){
if(f.isFile()){
if(f.getName().startsWith(prefix) && f.getName().endsWith(ext)){
System.out.println(f.getName());
return true;
}
}
else{
//This step starts looking inside subfolder as well
return checkForFile(f.getAbsolutePath(),prefix,ext);
}
}
return true;
}
To check a file inside a folder, You will need to use exists() method of java.io.File like this:
boolean exists = new File("FOLDER_PATH/FILE_NAME").exists();
if (exists) {
System.out.println("File exists inside given folder");
} else {
System.out.println("File does not exists inside given folder");
}
Also possible with FileVisitor:
#Getter #Setter
#RequiredArgsConstructor
public static class SearchVisitor extends SimpleFileVisitor<Path> {
private final String fileToSearch;
private boolean found=false;
#Override
public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
if(!file.getFileName().toString().equals(fileToSearch)) return FileVisitResult.CONTINUE;
found=true;
return FileVisitResult.TERMINATE;
}
}
public void test() throws IOException {
SearchVisitor sv = new SearchVisitor("LigaV2");
Files.walkFileTree( Paths.get(System.getProperty("user.dir")), sv);
log.info("found file {}:{}", sv.getFileToSearch(), sv.isFound());
}
Use public boolean isDirectory() in java file API following is the link to oracle documentation. Tests whether the file denoted by this abstract pathname is a directory.
https://docs.oracle.com/javase/7/docs/api/java/io/File.html#isDirectory()
Related
I need to get a list of all the files in a directory, including files in all the sub-directories. What is the standard way to accomplish directory iteration with Java?
You can use File#isDirectory() to test if the given file (path) is a directory. If this is true, then you just call the same method again with its File#listFiles() outcome. This is called recursion.
Here's a basic kickoff example:
package com.stackoverflow.q3154488;
import java.io.File;
public class Demo {
public static void main(String... args) {
File dir = new File("/path/to/dir");
showFiles(dir.listFiles());
}
public static void showFiles(File[] files) {
for (File file : files) {
if (file.isDirectory()) {
System.out.println("Directory: " + file.getAbsolutePath());
showFiles(file.listFiles()); // Calls same method again.
} else {
System.out.println("File: " + file.getAbsolutePath());
}
}
}
}
Note that this is sensitive to StackOverflowError when the tree is deeper than the JVM's stack can hold. If you're already on Java 8 or newer, then you'd better use Files#walk() instead which utilizes tail recursion:
package com.stackoverflow.q3154488;
import java.io.File;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
public class DemoWithJava8 {
public static void main(String... args) throws Exception {
Path dir = Paths.get("/path/to/dir");
Files.walk(dir).forEach(path -> showFile(path.toFile()));
}
public static void showFile(File file) {
if (file.isDirectory()) {
System.out.println("Directory: " + file.getAbsolutePath());
} else {
System.out.println("File: " + file.getAbsolutePath());
}
}
}
If you are using Java 1.7, you can use java.nio.file.Files.walkFileTree(...).
For example:
public class WalkFileTreeExample {
public static void main(String[] args) {
Path p = Paths.get("/usr");
FileVisitor<Path> fv = new SimpleFileVisitor<Path>() {
#Override
public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)
throws IOException {
System.out.println(file);
return FileVisitResult.CONTINUE;
}
};
try {
Files.walkFileTree(p, fv);
} catch (IOException e) {
e.printStackTrace();
}
}
}
If you are using Java 8, you can use the stream interface with java.nio.file.Files.walk(...):
public class WalkFileTreeExample {
public static void main(String[] args) {
try (Stream<Path> paths = Files.walk(Paths.get("/usr"))) {
paths.forEach(System.out::println);
} catch (IOException e) {
e.printStackTrace();
}
}
}
Check out the FileUtils class in Apache Commons - specifically iterateFiles:
Allows iteration over the files in given directory (and optionally its subdirectories).
Using org.apache.commons.io.FileUtils
File file = new File("F:/Lines");
Collection<File> files = FileUtils.listFiles(file, null, true);
for(File file2 : files){
System.out.println(file2.getName());
}
Use false if you do not want files from sub directories.
For Java 7+, there is also https://docs.oracle.com/javase/7/docs/api/java/nio/file/DirectoryStream.html
Example taken from the Javadoc:
List<Path> listSourceFiles(Path dir) throws IOException {
List<Path> result = new ArrayList<>();
try (DirectoryStream<Path> stream = Files.newDirectoryStream(dir, "*.{c,h,cpp,hpp,java}")) {
for (Path entry: stream) {
result.add(entry);
}
} catch (DirectoryIteratorException ex) {
// I/O error encounted during the iteration, the cause is an IOException
throw ex.getCause();
}
return result;
}
It's a tree, so recursion is your friend: start with the parent directory and call the method to get an array of child Files. Iterate through the child array. If the current value is a directory, pass it to a recursive call of your method. If not, process the leaf file appropriately.
As noted, this is a recursion problem. In particular, you may want to look at
listFiles()
In the java File API here. It returns an array of all the files in a directory. Using this along with
isDirectory()
to see if you need to recurse further is a good start.
You can also misuse File.list(FilenameFilter) (and variants) for file traversal. Short code and works in early java versions, e.g:
// list files in dir
new File(dir).list(new FilenameFilter() {
public boolean accept(File dir, String name) {
String file = dir.getAbsolutePath() + File.separator + name;
System.out.println(file);
return false;
}
});
To add with #msandiford answer, as most of the times when a file tree is walked u may want to execute a function as a directory or any particular file is visited. If u are reluctant to using streams. The following methods overridden can be implemented
Files.walkFileTree(Paths.get(Krawl.INDEXPATH), EnumSet.of(FileVisitOption.FOLLOW_LINKS), Integer.MAX_VALUE,
new SimpleFileVisitor<Path>() {
#Override
public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs)
throws IOException {
// Do someting before directory visit
return FileVisitResult.CONTINUE;
}
#Override
public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)
throws IOException {
// Do something when a file is visited
return FileVisitResult.CONTINUE;
}
#Override
public FileVisitResult postVisitDirectory(Path dir, IOException exc)
throws IOException {
// Do Something after directory visit
return FileVisitResult.CONTINUE;
}
});
I like to use Optional and streams to have a net and clear solution,
i use the below code to iterate over a directory. the below cases are handled by the code:
handle the case of empty directory
Laziness
but as mentioned by others, you still have to pay attention for outOfMemory in case you have huge folders
File directoryFile = new File("put your path here");
Stream<File> files = Optional.ofNullable(directoryFile// directoryFile
.listFiles(File::isDirectory)) // filter only directories(change with null if you don't need to filter)
.stream()
.flatMap(Arrays::stream);// flatmap from Stream<File[]> to Stream<File>
I did this simple experiment to list all files/directory in a parent directory.
Did this by making a java project in eclipse by name 'JavaProject' and a class 'Temp.java' under src/com. Code is as below:
public class Temp {
public static void main(String[] args) {
search("../JavaProject");
}
public static void search(String dName) {
String[] files = new String[100];
File search = new File(dName); // make file object
if (!search.isDirectory()) {
return;
}
files = search.list(); // create the list
for (String fn : files) {// iterate through it
System.out.print(" " + fn);
File temp = new File(fn);
if (temp.isDirectory()) {
search(fn);
}
System.out.println();
}
}
}
The file structure is as below :
JavaProject(dir)
.classpath(file)
.project(file)
.settings(dir)
org.eclipse.jdt.core.prefs(file)
bin(dir)
com(file)
Temp.class(file)
src(dir)
com(dir)
Temp.java(file)
When I run the above program, it gives the following output:
.classpath
.project
.settings org.eclipse.jdt.core.prefs
bin com
src com
I cant understand why it does not print the .java file and .class file inside the com folders.
When I try debugging then the file object on 'com' returns 'false' for both isDirectory() and isFile() methods.
When it gets to the 'com' directory your code is doing:
File temp = new File("com");
Since you have not specified any path this will be taken to be relative to the current directory which is not the directory containing 'com'.
You should use something like:
File temp = new File(parent, fn);
where parent is the File object for the parent directory.
You can use listFiles() instead of list(). See below example:
public class Program {
public static void main(String args[]) throws IOException {
search(new File("."), 0);
}
public static void search(File file, int level) {
if (!file.isDirectory()) {
return;
}
for (File f : file.listFiles()) {
for (int i = 0; i < level; i++) {
System.out.print(" ");
}
System.out.println(f.getName());
if (f.isDirectory()) {
search(f, ++level);
}
}
}
}
I am playing a bit with the new Java 7 IO features. Actually I am trying to retrieve all the XML files in a folder. However this throws an exception when the folder does not exist. How can I check if the folder exists using the new IO?
public UpdateHandler(String release) {
log.info("searching for configuration files in folder " + release);
Path releaseFolder = Paths.get(release);
try(DirectoryStream<Path> stream = Files.newDirectoryStream(releaseFolder, "*.xml")){
for (Path entry: stream){
log.info("working on file " + entry.getFileName());
}
}
catch (IOException e){
log.error("error while retrieving update configuration files " + e.getMessage());
}
}
Using java.nio.file.Files:
Path path = ...;
if (Files.exists(path)) {
// ...
}
You can optionally pass this method LinkOption values:
if (Files.exists(path, LinkOption.NOFOLLOW_LINKS)) {
There's also a method notExists:
if (Files.notExists(path)) {
Quite simple:
new File("/Path/To/File/or/Directory").exists();
And if you want to be certain it is a directory:
File f = new File("/Path/To/File/or/Directory");
if (f.exists() && f.isDirectory()) {
...
}
To check if a directory exists with the new IO:
if (Files.isDirectory(Paths.get("directory"))) {
...
}
isDirectory returns true if the file is a directory; false if the file does not exist, is not a directory, or it cannot be determined if the file is a directory or not.
See: documentation.
Generate a file from the string of your folder directory
String path="Folder directory";
File file = new File(path);
and use method exist.
If you want to generate the folder you sould use mkdir()
if (!file.exists()) {
System.out.print("No Folder");
file.mkdir();
System.out.print("Folder created");
}
You need to transform your Path into a File and test for existence:
for(Path entry: stream){
if(entry.toFile().exists()){
log.info("working on file " + entry.getFileName());
}
}
There is no need to separately call the exists() method, as isDirectory() implicitly checks whether the directory exists or not.
import java.io.File;
import java.nio.file.Paths;
public class Test
{
public static void main(String[] args)
{
File file = new File("C:\\Temp");
System.out.println("File Folder Exist" + isFileDirectoryExists(file));
System.out.println("Directory Exists" + isDirectoryExists("C:\\Temp"));
}
public static boolean isFileDirectoryExists(File file)
{
if (file.exists())
{
return true;
}
return false;
}
public static boolean isDirectoryExists(String directoryPath)
{
if (!Paths.get(directoryPath).toFile().isDirectory())
{
return false;
}
return true;
}
}
We can check files and thire Folders.
import java.io.*;
public class fileCheck
{
public static void main(String arg[])
{
File f = new File("C:/AMD");
if (f.exists() && f.isDirectory()) {
System.out.println("Exists");
//if the file is present then it will show the msg
}
else{
System.out.println("NOT Exists");
//if the file is Not present then it will show the msg
}
}
}
File sourceLoc=new File("/a/b/c/folderName");
boolean isFolderExisted=false;
sourceLoc.exists()==true?sourceLoc.isDirectory()==true?isFolderExisted=true:isFolderExisted=false:isFolderExisted=false;
From SonarLint, if you already have the path, use path.toFile().exists() instead of Files.exists for better performance.
The Files.exists method has noticeably poor performance in JDK 8, and can slow an application significantly when used to check files that don't actually exist.
The same goes for Files.notExists, Files.isDirectory and Files.isRegularFile.
Noncompliant Code Example:
Path myPath;
if(java.nio.Files.exists(myPath)) { // Noncompliant
// do something
}
Compliant Solution:
Path myPath;
if(myPath.toFile().exists())) {
// do something
}
I have the below code which checks to see if folder exists on the sdcard, I would like to add another if statement if the folder exists to check that there are zip files inside the actual folder if it in fact exists. What could i do to check the folder for a zip extension. The folder should have a lot of zips in it but i only want it to check to make sure there are zips and no other file extension. I thank you for any help with this.
File z = new File("/mnt/sdcard/folder");
if(!z.exists()) {
Toast.makeText(MainMethod.this, "/sdcard/folder Not Found!", Toast.LENGTH_LONG).show();
} else {
Toast.makeText(MainMethod.this, "/sdcard/folder Found!", Toast.LENGTH_LONG).show();
}
EDIT:
Thanks guys for the help here is what i ended up using with your help, i haven't tested it yet but it looks good to me.
File z = new File("/mnt/sdcard/Folder");
if(!z.exists()) {
//create folder
} else {
FilenameFilter f2 = new FilenameFilter() {
public boolean accept(File dir, String filename) {
return filename.endsWith("zip");
}
};
if (z.list(f2).length > 0) {
// there's a zip file in there..
} else {
//no zips inside folder
}
}
File f = new File("folder");
FilenameFilter f2 = new FilenameFilter() {
public boolean accept(File dir, String filename) {
return filename.endsWith("zip");
}
};
if (f.list(f2).length > 0) {
// there's a zip file in there..
}
Try the above..
Have you looked at FileNameFilter ?
File f = new File("/mnt/sdcard/folder");
if(e.exist()){//file exist ??
File[] matchingFiles = f.listFiles(new FilenameFilter() {
public boolean accept(File dir, String name) {
return name.endsWith("zip");
}
});//list out files with zip at the end
}
Here is the code I have thus far:
import java.io.*;
class JAVAFilter implements FilenameFilter {
public boolean accept(File dir, String name) {
return (name.endsWith(".java"));
}
}
public class tester {
public static void main(String args[])
{
FilenameFilter filter = new JAVAFilter();
File directory = new File("C:\\1.3\\");
String filename[] = directory.list(filter);
}
}
At this point, it'll store a list of all the *.java files from the directory C:\1.3\ in the string array filename. However, i'd like to store a list of all the java files also in subdirectories (preferably with their path within C:\1.3\ specified also. How do I go about doing this? Thanks!
you should look at DirectoryWalker from Apache
I'm afraid you can't do it with the list(FilenameFilter) method. You'll have to list all files and directories, and then do the filtering yourself. Something like this:
public List<File> getFiles(File dir, FilenameFilter filter) {
List<File> ret = new ArrayList<File>();
for (File f : dir.listFiles()) {
if (f.isDirectory()) {
ret.addAll(getFiles(f, filter));
} else if (filter.accept(dir, f.getName())) {
ret.add(f);
}
}
return ret;
}
As far as I know, you will have to do this manually (recursively), i.e. you will have to call list(filter) for all sub-directories of C:\1.3\, and so on....