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I have to filter files from Directory which matches the same file extension from ArrayList which I added

String folderpath = "G:\\AE_IntegrationComp";
//Above is Folder where is Different files are present
List <String>filet = new ArrayList<String>();
filet.add(".txt");
filet.add(".doc");
//extension which I added
for(String str : filet)
{
}
File directory = new File(folderpath);
for(File list : directory.listFiles())
{
if(list.getName().contains(""))
{
System.out.println(list.getName());
}
}
I have to check if Directory is empty or not
if not,
file extension in Arraylist should matched with extensions Are available in Directory
and print files that matched

What you wanna do is:
Iterate through all files into a directory (which you have done)
Check if it has a certain extension (it ends with a certain string)
Print the file name if that matches.
public class Main {
// Here we have a constant containing the interesting file extensions
public static final String[] extensions = new[] { ".txt", ".doc" };
// This helper function will tell us whether
// a file has one of the interesting file extensions
public static boolean matchesExtension(File file) {
for(String ext : extensions) {
if(file.getName().endsWith(ext)) {
return true;
}
}
return false;
}
public static void main(String[] args) {
String folderpath = "G:\\AE_IntegrationComp";
File directory = new File(folderpath);
// Iterate through all files in the directory
for(File file : directory.listFiles()){
if(matchesExtension(file)){
System.out.println(file.getName());
}
}
}
}

How to get sub path from the given file path

I want to get path after given token "html" which is a fix token and file path is below
String token = "html"
Path path = D:\data\test\html\css\Core.css
Expected Output : css\Core.css
below is input folder for the program. and defined as the constant in the code.
public static final String INPUT_DIR = "D:\data\test\html"
which will contains input html, css, js files. and want to copy these files to different location E:\data\test\html\ here so just need to extract sub path after html from the input file path to append it to the output path.
lets say input file are
D:\data\test\html\css\Core.css
D:\data\test\html\css\Core.html
D:\data\test\html\css\Core.js
so want to extract css\Core.css, css\Core.html, css\Core.js to append it to the destination path E:\data\test\html\ to copy it.
Tried below
String [] array = path.tostring().split("html");
String subpath = array[1];
Output : \css\Core.css
which is not expected output expected output is css\Core.css
Also above code is not working for below path
Path path = D:\data\test\html\bla\bla\html\css\Core.css;
String [] array = path.toString().split("html");
String subpath = array[1];
In this case I am getting something like \bla\bla\ which is not
expected.

If you only need the path in the form of a string another solution would be to use this code:
String path = "D:\\data\\test\\html\\css\\Core.css";
String keyword = "\\html";
System.out.println(path.substring(path.lastIndexOf(keyword) + keyword.length()).trim());
You can replace the path with file.getAbsolutePath() as mentioned above.

import java.io.File;
public class Main {
public static void main(String[] args) {
// Create a File object for the directory that you want to start from
File directory = new File("/path/to/starting/directory");
// Get a list of all files and directories in the directory
File[] files = directory.listFiles();
// Iterate through the list of files and directories
for (File file : files) {
// Check if the file is a directory
if (file.isDirectory()) {
// If it's a directory, recursively search for the file
findFile(file, "target-file.txt");
} else {
// If it's a file, check if it's the target file
if (file.getName().equals("target-file.txt")) {
// If it's the target file, print the file path
System.out.println(file.getAbsolutePath());
}
}
}
}
public static void findFile(File directory, String targetFileName) {
// Get a list of all files and directories in the directory
File[] files = directory.listFiles();
// Iterate through the list of files and directories
for (File file : files) {
// Check if the file is a directory
if (file.isDirectory()) {
// If it's a directory, recursively search for the file
findFile(file, targetFileName);
} else {
// If it's a file, check if it's the target file
if (file.getName().equals(targetFileName)) {
// If it's the target file, print the file path
System.out.println(file.getAbsolutePath());
}
}
}
}
}
This code uses a recursive function to search through all subdirectories of the starting directory and print the file path of the target file (in this case, "target-file.txt") if it is found.
You can modify this code to suit your specific needs, such as changing the starting directory or target file name. You can also modify the code to perform different actions on the target file, such as reading its contents or copying it to another location.

Your question lacks details.
Is the "path" a Path or a String?
How do you determine which part of the "path" you want?
Do you know the entire structure of the "path" or do you just have the delimiting part, for example the html?
Here are six different ways (without iterating, as you stated in your comment). The first two use methods of java.nio.file.Path. The next two use methods of java.lang.String. The last two use regular expressions. Note that there are probably also other ways.
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class PathTest {
public static void main(String[] args) {
// D:\data\test\html\css\Core.css
Path path = Paths.get("D:", "data", "test", "html", "css", "Core.css");
System.out.println("Path: " + path);
Path afterHtml = Paths.get("D:", "data", "test", "html").relativize(path);
System.out.println("After 'html': " + afterHtml);
System.out.println("subpath(3): " + path.subpath(3, path.getNameCount()));
String str = path.toString();
System.out.println("replace: " + str.replace("D:\\data\\test\\html\\", ""));
System.out.println("substring: " + str.substring(str.indexOf("html") + 5));
System.out.println("split: " + str.split("\\\\html\\\\")[1]);
Pattern pattern = Pattern.compile("\\\\html\\\\(.*$)");
Matcher matcher = pattern.matcher(str);
if (matcher.find()) {
System.out.println("regex: " + matcher.group(1));
}
}
}
Running the above code produces the following output:
Path: D:\data\test\html\css\Core.css
After 'html': css\Core.css
subpath(3): css\Core.css
replace: css\Core.css
substring: css\Core.css
split: css\Core.css
regex: css\Core.css
I assume you know how to modify the above in order to
I want to get file path after /test

How to access the folder name from the directory

I want to get the name of the folders from directory who only have .c and .h files.
below is my code but I am not getting that how exactly I can get the folder names who only have .c and .h files.
File directory = new File(directoryName);
//get all the files from a directory
if(directory.exists()){
File[] fList = directory.listFiles();
for (File file : fList){
if (file.isDirectory()){
System.out.println(file.getName());
System.out.println(file.getAbsolutePath());
}
Above code will take the input path for directory and prints the name of all sub folders or sub directories if the main directory is exist.and also prints the path.Now I only want the name of all sub folders from directory which have .c and .h files.
Thanks If anyone help me.

Try to take a look at Apache's DirectoryScanner
Using that we can mention the file extension types to be considered/omitted
DirectoryScanner scanner = new DirectoryScanner();
scanner.setIncludes(new String[]{"*.c", "*.h"});
https://ant.apache.org/manual/api/org/apache/tools/ant/DirectoryScanner.html

You can use a list and getParent() function like:
List<String> list;
File directory = new File(directoryName);
if(directory.exists()){
File[] fList = directory.listFiles();
for (File file : fList){
if (file.isDirectory()){
System.out.println(file.getName());
if(file.getName().contains(".c") || file.getName().contains(".h"))
list.add(file.getParent());
System.out.println(file.getAbsolutePath());
}
}
}
for(String item : list) {
System.out.println(item);
}

I've given a pure Java solution here, but if your directory structure is too deep or directories have thousands of files, this may not work out. In that case you may have to run an OS command and dump the output into Java. For instance if you use Unix (or Unix-based) system, you can use find to list directories and invoke the command from Java using ProcessBuilder.
Now the Java solution:
Create a custom FileNameFilter first. This will filter files based on extensions you pass.
public class ExtensionFilter implements FilenameFilter {
private String[] extensions;
public ExtensionFilter(String... extensions) {
this.extensions = extensions;
}
#Override
public boolean accept(File dir, String name) {
for (String extension : extensions) {
if ( name.toLowerCase().endsWith(extension.toLowerCase()) ) {
return true;
}
}
return false;
}
}
Create a FileFilter to help you filter for only directories (for recursion)
public class FolderFilter implements FileFilter {
#Override
public boolean accept(File path) {
return path.isDirectory();
}
}
Use recursion to build list of folder paths contains files with the given extension.
private static final FolderFilter folderFilter = new FolderFilter();
public List<String> recursiveSearch(File base, ExtensionFilter extFilter) {
List<String> paths = new ArrayList<>();
//Does current directory itself have files of given extension?
if (base.list(extFilter).length > 0) {
paths.add(base.getPath()); //Use base.getName() here instead, for just name
}
// Recurse through current directory's subfolders
for (File dir : base.listFiles(folderFilter)) {
paths.addAll(recurse(dir, extFilter));
}
return paths;
}
Finally, invoke it like so:
String basePath = "...";
File baseDir = new File(basePath);
ExtensionFilter extFilter = new ExtensionFilter(".c",".h");
List<String> folders = recurse(baseDir, extFilter);
This will now contain all paths (or names as mentioned above) of folders which have files with given extensions.

How to merge two Folder files into one in Java

I am trying to create a simple function which copies or merge two or more folder files into one single folder.
I started with below. I thought to post here to get a better quality code.
public void copyDifferentFolderFilesIntoOne(String mergedFolderStr,String ... foldersStr)
{
File mergedFolder= new File(mergedFolderStr);
for(String folder: foldersStr)
{
//copy folder's files into mergedFolder
}
}
When there is a conflict in file copying (i.e. file with same name exists on two or more folder) I want the file with latest timestamp get copied in mergedFolder.
Do you know the best way to merge two or more folders files into one?
Let me know if question is not clear.

You can create a Map<String, File> of the files you want to copy by traversing the merged dirs and keeping the newest files. Then you can copy the files you have in a map.
A sample code (haven't tried it) might look like this:
public void copyDifferentFolderFilesIntoOne(String mergedFolderStr,
String... foldersStr) {
final File mergedFolder = new File(mergedFolderStr);
final Map<String, File> filesMap = new HashMap<String, File> ();
for (String folder : foldersStr) {
updateFilesMap(new File (folder), filesMap, null);
}
for (final Map.Entry<String, File> fileEntry : filesMap.entrySet()) {
final String relativeName = fileEntry.getKey();
final File srcFile = fileEntry.getValue();
FileUtils.copyFile (srcFile, new File (mergedFolder, relativeName));
}
}
private void updateFilesMap(final File baseFolder, final Map<String, File> filesMap,
final String relativeName) {
for (final File file : baseFolder.listFiles()) {
final String fileRelativeName = getFileRelativeName (relativeName, file.getName());
if (file.isDirectory()) {
updateFilesMap(file, filesMap, fileRelativeName);
}
else {
final File existingFile = filesMap.get (fileRelativeName);
if (existingFile == null || file.lastModified() > existingFile.lastModified() ) {
filesMap.put (fileRelativeName, file);
}
}
}
}
private String getFileRelativeName(final String baseName, final String fileName) {
return baseName == null ? fileName : baseName + "/" + fileName;
}

To copy file, look at Standard concise way to copy a file in Java?
To get timestamp, see File.lastModified()

Delete Files with same Prefix String using Java

I have around 500 text files inside a directory with each with the same prefix in their filename, for example: dailyReport_.
The latter part of the file is the date of the file. (For example dailyReport_08262011.txt, dailyReport_08232011.txt)
I want to delete these files using a Java procedure. (I could go for a shell script and add it a job in the crontab but the application is meant to used by laymen).
I can delete a single file using something like this:
try{
File f=new File("dailyReport_08232011.txt");
f.delete();
}
catch(Exception e){
System.out.println(e);
}
but can I delete the files having a certain prefix? (e.g. dailyReport08 for the 8th month) I could easily do that in shell script by using rm -rf dailyReport08*.txt .
But File f=new File("dailyReport_08*.txt"); doesnt work in Java (as expected).
Now is anything similar possible in Java without running a loop that searches the directory for files?
Can I achieve this using some special characters similar to * used in shell script?

No, you can't. Java is rather low-level language -- comparing with shell-script -- so things like this must be done more explicetly. You should search for files with required mask with folder.listFiles(FilenameFilter), and iterate through returned array deleting each entry. Like this:
final File folder = ...
final File[] files = folder.listFiles( new FilenameFilter() {
#Override
public boolean accept( final File dir,
final String name ) {
return name.matches( "dailyReport_08.*\\.txt" );
}
} );
for ( final File file : files ) {
if ( !file.delete() ) {
System.err.println( "Can't remove " + file.getAbsolutePath() );
}
}

You can use a loop
for (File f : directory.listFiles()) {
if (f.getName().startsWith("dailyReport_")) {
f.delete();
}
}

Java 8 :
final File downloadDirectory = new File("directoryPath");
final File[] files = downloadDirectory.listFiles( (dir,name) -> name.matches("dailyReport_.*?" ));
Arrays.asList(files).stream().forEach(File::delete)

With Java 8:
public static boolean deleteFilesForPathByPrefix(final String path, final String prefix) {
boolean success = true;
try (DirectoryStream<Path> newDirectoryStream = Files.newDirectoryStream(Paths.get(path), prefix + "*")) {
for (final Path newDirectoryStreamItem : newDirectoryStream) {
Files.delete(newDirectoryStreamItem);
}
} catch (final Exception e) {
success = false;
e.printStackTrace();
}
return success;
}
Simple version:
public static void deleteFilesForPathByPrefix(final Path path, final String prefix) {
try (DirectoryStream<Path> newDirectoryStream = Files.newDirectoryStream(path, prefix + "*")) {
for (final Path newDirectoryStreamItem : newDirectoryStream) {
Files.delete(newDirectoryStreamItem);
}
} catch (final Exception e) { // empty
}
}
Modify the Path/String argument as needed. You can even convert between File and Path. Path is preferred for Java >= 8.

I know I'm late to the party. However, for future reference, I wanted to contribute a java 8 stream solution that doesn't involve a loop.
It may not be pretty. I welcome suggestions to make it look better. However, it does the job:
Files.list(deleteDirectory).filter(p -> p.toString().contains("dailyReport_08")).forEach((p) -> {
try {
Files.deleteIfExists(p);
} catch (Exception e) {
e.printStackTrace();
}
});
Alternatively, you can use Files.walk which will traverse the directory depth-first. That is, if the files are buried in different directories.

Use FileFilter like so:
File dir = new File(<path to dir>);
File[] toBeDeleted = dir.listFiles(new FileFilter() {
boolean accept(File pathname) {
return (pathname.getName().startsWith("dailyReport_08") && pathname.getName().endsWith(".txt"));
}
for (File f : toBeDeleted) {
f.delete();
}

There isn't a wildcard but you can implement a FilenameFilter and check the path with a startsWith("dailyReport_"). Then calling File.listFiles(filter) gives you an array of Files that you can loop through and call delete() on.

I agree with BegemoT.
However, just one optimization:
If you need a simple FilenameFilter, there is a class in the Google packages.
So, in this case you do not even have to create your own anonymous class.
import com.google.common.io.PatternFilenameFilter;
final File folder = ...
final File[] files = folder.listFiles(new PatternFilenameFilter("dailyReport_08.*\\.txt"));
// loop through the files
for ( final File file : files ) {
if ( !file.delete() ) {
System.err.println( "Can't remove " + file.getAbsolutePath() );
}
}
Enjoy !

You can't do it without a loop. But you can enhance this loop. First of all, ask you a question: "what's the problem with searching and removing in the loop?" If it's too slow for some reason, you can just run your loop in a separate thread, so that it will not affect your user interface.
Other advice - put your daily reports in a separate folder and then you will be able to remove this folder with all content.

or in scala
new java.io.File(<<pathStr>>).listFiles.filter(_.getName.endsWith(".txt")).foreach(_.delete())

Have a look at Apache FileUtils which offers many handy file manipulations.