Develop Reference

How to download a file into the specific folder in java?

I am working on an application which will download 3rd party dependencies to a particular folder and then execute dependency check on it. The files downloaded can be of any type, they can be zip, jar or may b a folder. I am trying to find a code example but nothing seems to work for me. I tried NIO in java but that seems to work only for writing to a particular file not folder. Below is code where I used NIO
// Checking If The File Exists At The Specified Location Or Not
Path filePathObj = Paths.get(filePath);
boolean fileExists = Files.exists(filePathObj);
if(fileExists) {
try {
urlObj = new URL(sampleUrl);
rbcObj = Channels.newChannel(urlObj.openStream());
fOutStream = new FileOutputStream(filePath);
fOutStream.getChannel().transferFrom(rbcObj, 0, Long.MAX_VALUE);
System.out.println("! File Successfully Downloaded From The Url !");
} catch (IOException ioExObj) {
System.out.println("Problem Occured While Downloading The File= " + ioExObj.getMessage());
} finally {
try {
if(fOutStream != null){
fOutStream.close();
}
if(rbcObj != null) {
rbcObj.close();
}
} catch (IOException ioExObj) {
System.out.println("Problem Occured While Closing The Object= " + ioExObj.getMessage());
}
}
} else {
System.out.println("File Not Present! Please Check!");
}```

public Class CopyAndWrite {
public static final String SOURCES = "C:\\Users\\Administrator\\Desktop\\resources";
public static final String TARGET = "C:\\Users\\Administrator\\Desktop\\111";
public static void main (String[]args) throws IOException {
Path startingDir = Paths.get(SOURCES);
Files.walkFileTree(startingDir, new FindJavaVisitor());
}
private static class FindJavaVisitor extends SimpleFileVisitor<Path> {
#Override
public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException {
if (!StringUtils.equals(dir.toString(), SOURCES)) {
Path targetPath = Paths.get(TARGET + dir.toString().substring(SOURCES.length()));
if (!Files.exists(targetPath)) {
Files.createDirectory(targetPath);
}
}
return FileVisitResult.CONTINUE;
}
#Override
public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
Path targetPath = Paths.get(TARGET + file.toString().substring(SOURCES.length()));
copyFile(targetPath, Files.readAllBytes(file));
return FileVisitResult.CONTINUE;
}
}
private static void copyFile (Path path,byte[] bytes){
// write file
try {
Files.write(path, bytes);
} catch (IOException e) {
e.printStackTrace();
}
}
}

Using OKHttpClient to download the file and place in a folder.
Request request = new Request.Builder().url(downloadUrl).build();
Response response;
try {
response = client.newCall(request).execute();
if (response.isSuccessful()) {
fileName = abc.zip
Path targetPath = new File(inDir + File.separator + fileName).toPath();
try (FileOutputStream fos = new FileOutputStream(targetPath)) {
fos.write(response.body().bytes());
}
return 0;
}
} catch (IOException e) {
logger.error(e.getMessage());
}```

Recursively finding directory based on pattern

public static printFnames(String sDir) {
Files.find(Paths.get(sDir), 999, (p, bfa) -> bfa.isRegularFile()).forEach(System.out::println);
}
Given something like above, or using Apache IO or Java NIO, how can I recursively look for directory that match the following pattern:
COB03Oct2017 (which resembles last working day basically)
I have a structure like /sourcefolder/clientfolders/COB03Oct2017/file.pdf
There are many clientfolders and many COBddmmyyyy folders.
Let's say I have already got a method that gives me the cob folder name.
How can I find all matching cob folders for all client folders?
#Test
public void testFiles() {
String sourcePath = "C:\\sourcepath\\";
String cobPattern = "COB" + DateHelper.getPreviousWorkingDay();
List<Path> clientDirectories = null;
try {
clientDirectories = Files.find(Paths.get(sourcePath), 1,
(path, bfa) -> bfa.isDirectory())
.collect(Collectors.toList());
} catch (IOException e) {
e.printStackTrace();
}
List<Path> cobDirectories = getCobDirectories(clientDirectories, cobPattern);
}
private List<Path> getCobDirectories(List<Path> clientDirectories, String cobPattern) {
List<Path> collect = new ArrayList<>();
clientDirectories
.stream()
.forEach(path -> {
try {
collect.addAll(Files.find(Paths.get(path.toString()), 1,
(p, bfa) -> bfa.isDirectory()
&& p.getFileName().toString().equals(cobPattern)).collect(Collectors.toList()));
} catch (IOException e) {
e.printStackTrace();
}
});
System.out.println("Done");
return collect;
}
The above is my attempt. But with your help, I would like to know if I am doing anything wrong, how it can be written better etc
This bit also worked. But again can this be improved? How do ignore exceptions such AccessDenied
#Test
public void testFiles() {
String sourcePath = "\\\\server\\pathToCustomerReports\\";
String cobPattern = "COB" + DateHelper.getPreviousWorkingDay();
List<Path> clientDirectories = null;
try {
clientDirectories = Files.find(Paths.get(sourcePath), 1,
(path, bfa) -> bfa.isDirectory())
.collect(Collectors.toList());
} catch (IOException e) {
e.printStackTrace();
}
List<Path> cobDirectories = new ArrayList<>();
clientDirectories.forEach(path -> cobDirectories.addAll(getCobdirs(path)));
System.out.println("Done");
}
private List<Path> getCobdirs(Path path) {
List<Path> cobDirs = new ArrayList<>();
String cobPattern = "COB" + DateHelper.getPreviousWorkingDay();
try (DirectoryStream<Path> stream = Files.newDirectoryStream(path)) {
for (Path p : stream) {
if (path.toFile().isDirectory() && p.getFileName().toString().equals(cobPattern)) {
cobDirs.add(p);
}
}
} catch (IOException e) {
e.printStackTrace();
}
return cobDirs;
}

This is what I have tried to find the specific folder in your SourceFolder. I have used Java's file.fileList(filter)
public abstract class ChooseFile {
public static File parent = new File("your/path/name");
public static void main(String args[]) throws IOException {
printFnames(parent.getAbsolutePath());
}
public static void printFnames(String sDir) throws IOException {
// Take action only when parent is a directory
if (parent.isDirectory()) {
File[] children = parent.listFiles(new FileFilter() {
public boolean accept(File file) {
if (file.isDirectory() && file.getName().equalsIgnoreCase("YourString")) // I have serached for "bin" folders in my Source folder.
System.out.println(file.getAbsolutePath());
else if (file.isDirectory())
try {
parent = file;
printFnames(file.getAbsolutePath());
}
catch (IOException exc) {
// TODO Auto-generated catch block
exc.printStackTrace();
}
return file.isDirectory() || file.getName().toLowerCase().contains("YourString");
}
});
}
}
}
This would return all the folders which contains the string "YourString" as a name. In case, if you want to match the names with regex then you need to change the method .equalsIgnoreCase("YourString") to .matches("YourRegex"). I think that should work.
Cheers.

An alternative approach can be a recursive method, that will dig as deep as needed to find the specified folder:
public static void main(String[] args) {
//the directory to search. It will search the whole tree
//so it should work also for sourcePath = "c:\\";
String sourcePath = "c:\\sourcepath\\";
String cobPattern = "COB03Oct2017";
List<Path> cobDirectories = getCobDirectories(sourcePath, cobPattern);
cobDirectories.forEach(p -> System.out.println(p)); //check output
}
private static List<Path> getCobDirectories(String sourcePath, String cobPattern) {
List<Path> cobDirs = new ArrayList<>();
getCobDirectories(sourcePath,cobPattern, cobDirs);
return cobDirs;
}
private static void getCobDirectories(String sourcePath, String cobPattern, List<Path> cobDirs) {
File file = new File(sourcePath);
if( ! file.isDirectory()) {//search only in folders
return;
}
if(file.getName().equals(cobPattern)) {//add to collection
cobDirs.add(Paths.get(sourcePath));
return;
}
if(file.list() == null) {//for abstract path or errors
return;
}
for (String fileName: file.list() ){
getCobDirectories((sourcePath+"\\"+fileName),cobPattern, cobDirs);
}
}

Finding last folder in list of folders

Is there any faster method to find a folder that has no other folders inside?
File dir = new File("C:\\Users\\axs0552\\Desktop\\barcode\\");
File[] cartella = dir.listFiles();
List<String> Nome_cartela = null;
if (cartella == null) {
logger.debug("ERRORE: cartella inesistente, oppure directoy errata !!");
} else {
for (int i = 0; i < cartella.length; i++) {
if (cartella[i].isDirectory()) {
System.out.println("cartella radice n° :" + i + " " + cartella[i].getName());
File[] figli = cartella[i].listFiles();
for (int j = 0; i < figli.length; i++) {
if (figli[i].isDirectory()) {
System.out.println("cartella figlio n° :" + j + " " + figli[i].getName());
}
}
}
}
}

If you want to recursively examine all directories I suggest using a FileVisitor. This is a simple example that just outputs all names on entering and leaving and counts the directories:
public class MyFileVisitor implements FileVisitor<Path> {
private int dirCount = 0;
#Override
public FileVisitResult preVisitDirectory(Path path, BasicFileAttributes bfa) throws IOException {
System.out.println("Entering directory: " + path);
dirCount++;
return FileVisitResult.CONTINUE;
}
#Override
public FileVisitResult postVisitDirectory(Path path, IOException ex) throws IOException {
System.out.println("Leaving directory: " + path);
return FileVisitResult.CONTINUE;
}
#Override
public FileVisitResult visitFile(Path path, BasicFileAttributes bfa) throws IOException {
return FileVisitResult.CONTINUE;
}
#Override
public FileVisitResult visitFileFailed(Path path, IOException ex) throws IOException {
return FileVisitResult.CONTINUE;
}
public int getDirCount() {
return dirCount;
}
}
main could look like this:
public class Main {
public static void main(String[] args) {
Path path = Paths.get("c:/users");
MyFileVisitor fileVisitor = new MyFileVisitor();
try {
Files.walkFileTree(path, fileVisitor);
System.out.println(fileVisitor.getDirCount() + " directories");
} catch (IOException ex) {
ex.printStackTrace();
}
}
}

If you only want to have the logic from your script you could write it like this (note that findFolderWihtoutSubfolders is static only for simplicity of main):
package tests;
import java.io.File;
public class Directories {
public static File findFolderWithoutSubfolders(File dir) {
for (File f : dir.listFiles()) {
if (f.isDirectory()) {
boolean flag = true;
for (File ff : f.listFiles()) {
if (ff.isDirectory()) {
flag = false;
break;
}
}
if (flag) {
return f;
}
}
}
return null;
}
public static void main(String[] args) {
File f = findFolderWithoutSubfolders(new File("C:\\Users\\stack\\test"));
if (f != null) {
System.out.println("Folder is : " + f.getName());
} else {
System.out.println("no folder found");
}
}
}

The simple way to print all empty directories below a root directory could be the below snippet.
assuming the follwing structure (file are named *.file)
/tmp/foo
/tmp/foo/bar
/tmp/foo/bar/bar.file
/tmp/foo/bar/barfoo
/tmp/foo/bar/foobar
/tmp/foo/bar/foobar/foobar.file
/tmp/foo/bar.file
/tmp/foo/baz
The snippet
Path rootPath = Paths.get("/tmp/foo");
Files.walk(rootPath, FileVisitOption.FOLLOW_LINKS)
.map(Path::toFile)
.filter((file) -> file.isDirectory() && file.listFiles().length == 0)
.forEach(System.out::println);
output
/tmp/foo/bar/barfoo
/tmp/foo/baz
the following directories are not printed
/tmp/foo/bar - contains subdirectories and a file
/tmp/foo/bar - contains a file

the method is not recursive. only two levels are checked. tree browsing is achieved using the file tree walking from nio2
import java.io.File;
import java.io.FileFilter;
// yet another file util class
public class YAFU {
public static void main(String[] args) {
File[] simpleFolders = YAFU.simpleFolders(new File("/tmp"));
if (simpleFolders == null)
System.out.println("nothing found");
else
for (File f : simpleFolders) {
System.out.println(f.getName());
}
}
public static boolean containsDirectories(File file) {
if (file == null || !file.isDirectory()) {
return false;
} else {
File[] found = file.listFiles(new FileFilter() {
#Override
public boolean accept(File file) {
return file.isDirectory();
}
});
return (found == null) ? false : found.length > 0;
}
}
public static File[] simpleFolders(File rootDir) {
if (rootDir == null || !rootDir.isDirectory()) {
return null;
} else {
return rootDir.listFiles(new FileFilter() {
#Override
public boolean accept(File file) {
return containsDirectories(file);
}
});
}
}
}

you can do following
public class LastFolderFinder {
public static void main(final String[] args){
final Path dir = Paths.get("C:\\Users\\axs0552\\Desktop\\barcode\\");
visitDir(dir);
}
private static void visitDir(final Path dir) {
try (final DirectoryStream<Path> directoryStream = Files.newDirectoryStream(dir, new DirectoryFilter());) {
final Iterator<Path> iterator = directoryStream.iterator();
if (iterator.hasNext()) {
while (iterator.hasNext()) {
final Path next = iterator.next();
visitDir(next);
}
} else {
System.out.println("last directory: " + dir);
}
} catch (final Exception exception) {
exception.printStackTrace();
}
}
}
class DirectoryFilter implements Filter<Path> {
#Override
public boolean accept(final Path entry) throws IOException {
return entry.toFile().isDirectory();
}
}

or you can do following updated https://stackoverflow.com/a/36084399/3333885 a little
public class LastFolderFinder {
public static void main(final String[] args) throws IOException {
final Path dir = Paths.get("C:\\Users\\axs0552\\Desktop\\barcode\\");
Files.walkFileTree(dir, new SimpleFileVisitor<Path>() {
#Override
public FileVisitResult preVisitDirectory(final Path path, final BasicFileAttributes bfa) throws IOException {
if (hasDirectories(path)) {
return FileVisitResult.CONTINUE;
}
System.err.println(path);
return FileVisitResult.SKIP_SUBTREE;
}
#Override
public FileVisitResult postVisitDirectory(final Path path, final IOException ex) throws IOException {
return FileVisitResult.CONTINUE;
}
#Override
public FileVisitResult visitFile(final Path path, final BasicFileAttributes bfa) throws IOException {
return FileVisitResult.CONTINUE;
}
});
}
private static boolean hasDirectories(final Path dir) {
try (final DirectoryStream<Path> directoryStream = Files.newDirectoryStream(dir, new DirectoryFilter());) {
final Iterator<Path> iterator = directoryStream.iterator();
return iterator.hasNext();
} catch (final Exception exception) {
exception.printStackTrace();
}
return false;
}
}
class DirectoryFilter implements Filter<Path> {
#Override
public boolean accept(final Path entry) throws IOException {
return entry.toFile().isDirectory();
}
}

The WatchEvent's context doesn't reflect renaming of the directory

I'm trying to implement a recursive directory watching functionality. But I found the API very hard to understand.
Let's say I have an empty directory which is the root of the directory tree I would like to watch. Now I create a new directory within this root (it's default name is 'New folder' in Windows 7) and I immediately rename it to something like 'xxx'.
The problem is when I copy a file in the new created 'xxx' directory. The WatchEvent's context is 'New folder' instead of the 'xxx'.
Here is my sscce:
public class Test {
private static final String SRC_DIR = "D:/test";
private final WatchService watcherService;
public Test() throws IOException {
watcherService = FileSystems.getDefault().newWatchService();
registerDirectoryTree(Paths.get(SRC_DIR));
startWatching();
}
private void startWatching() throws IOException {
while (true) {
WatchKey watchKey;
try {
watchKey = watcherService.take();
} catch (InterruptedException e) {
break;
}
Path directory = null;
try {
directory = (Path) watchKey.watchable();
for (WatchEvent<?> event : watchKey.pollEvents()) {
if (event.kind() == StandardWatchEventKinds.ENTRY_CREATE) {
Path fileName = (Path) event.context();
Path filePath = directory.resolve(fileName);
if (Files.isDirectory(filePath, LinkOption.NOFOLLOW_LINKS)) {
registerDirectoryTree(filePath);
} else if (Files.isRegularFile(filePath, LinkOption.NOFOLLOW_LINKS)) {
System.out.println("Processing file. Path: " + filePath);
} else {
System.out.println("Unknown path type. Path: " + filePath);
}
}
}
} finally {
boolean valid = watchKey.reset();
if (!valid) {
System.out.println("Watch key is not valid. Directory: " + directory);
}
}
}
}
private void registerDirectoryTree(Path sourceDir) throws IOException {
Files.walkFileTree(sourceDir, new SimpleFileVisitor<Path>() {
#Override
public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException {
registerDirectory(dir);
return FileVisitResult.CONTINUE;
}
});
}
private void registerDirectory(Path path) throws IOException {
System.out.println("Registering watch service on " + path);
path.register(watcherService, StandardWatchEventKinds.ENTRY_CREATE);
}
public static void main(String[] args) throws IOException {
new Test();
}
}

how to get/ make file object in the program given below

i am a nibble in java. i have my own efforts to get the things done. but certainly i am facing a challenge. i have a dummy program that searches for files of a particular extension(.txt) supplied as a command line argument. i am trying to make file objects of these searched file for further manipulations. but i can't understand how to do this in my code.. here is my code sample...
public class Find {
public static class Finder extends SimpleFileVisitor<Path> {
private final PathMatcher matcher;
private int numMatches = 0;
Finder(String pattern) {
matcher = FileSystems.getDefault().getPathMatcher("glob:" + pattern);
}
void find(Path file) {
Path name = file.getFileName();
if (name != null && matcher.matches(name)) {
numMatches++;
System.out.println(file);
}
}
// Prints the total number of
// matches to standard out.
void done() {
System.out.println("Matched: "+ numMatches);
}
// Invoke the pattern matching
// method on each file.
//#Override
public FileVisitResult visitFile(Path file,
BasicFileAttributes attrs) {
find(file);
return CONTINUE;
}
// Invoke the pattern matching
// method on each directory.
//#Override
public FileVisitResult preVisitDirectory(Path dir,
BasicFileAttributes attrs) {
find(dir);
return CONTINUE;
}
//#Override
public FileVisitResult visitFileFailed(Path file, IOException exc) {
System.err.println(exc);
return CONTINUE;
}
}
public static void main(String[] args) throws IOException {
Iterable<Path> root;
root = FileSystems.getDefault().getRootDirectories();
// System.out.println(name.getAbsolutePath());
for (Path startingDir : FileSystems.getDefault().getRootDirectories()) {
String pattern = args[0];
Finder finder = new Finder(pattern);
Files.walkFileTree(startingDir, finder);
}
}
}

here is what i am trying to do. the output of my program is a long list of text files with their absolute path. now i want to make objects of these files so that i can upload these to a URL. to upload them i have to make a stream with file object to be sent..how to get absoluteFilename?? to get this you must have a file object...right.... and my revised question is : how to make file objects of searched files???
FileInputStream fileInputStream = null;
try {
new FileInputStream("absoluteFilename");
byte[] buffer = new byte[MAX_SIZE];
int bufferIndex = 0;
while (fileInputStream.available() > 0) {
buffer[bufferIndex++] = (byte) fileInputStream.read();
}
byte[] fileContent = new byte[bufferIndex];
System.arraycopy(buffer,0,fileContent,0,bufferIndex);
URL serverUrl = new URL(url);
URLConnection connection = serverURL.openConnection();
connection.setConnectTimeout(60000);
connection.getOutputStream().write(fileContent);
} catch (Exception fatal) {
//proper handling??