how to backup file in java? - java

In reality its just making a copy of a text.txt file. I know how to use file chooser to choose the file but that is as far as my knowledge really goes.
I can do this:
public BasicFile()
{
JFileChooser choose = new JFileChooser(".");
int status = choose.showOpenDialog(null);
try
{
if (status != JFileChooser.APPROVE_OPTION) throw new IOException();
f = choose.getSelectedFile();
if (!f.exists()) throw new FileNotFoundException();
}
catch(FileNotFoundException e)
{
display(1, e.toString(), "File not found ....");
}
catch(IOException e)
{
display(1, e.toString(), "Approve option was not selected");
}
}

Path object is perfect for copying files,
Try this code to copy a file,
Path source = Paths.get("c:\\blabla.txt");
Path target = Paths.get("c:\\blabla2.txt");
try {
Files.copy(source, target);
} catch (IOException e1) {
e1.printStackTrace();
}

If you have to backup a whole folder, you can use this code
public class BackUpFolder {
public void copy(File sourceLocation, File targetLocation) throws IOException {
if (sourceLocation.isDirectory()) {
copyDirectory(sourceLocation, targetLocation);
} else {
copyFile(sourceLocation, targetLocation);
}
}
private void copyDirectory(File source, File target) throws IOException {
if (!target.exists()) {
target.mkdir();
}
for (String f : source.list()) {
copy(new File(source, f), new File(target, f));
}
}
private void copyFile(File source, File target) throws IOException {
try (
InputStream in = new FileInputStream(source);
OutputStream out = new FileOutputStream(target)) {
byte[] buf = new byte[1024];
int length;
while ((length = in.read(buf)) > 0) {
out.write(buf, 0, length);
}
}
}
public static void main(String[] args) {
try {
BackUpFolder backUpFolder = new BackUpFolder();
String location = "./src/edu/abc/locationFiles/daofile"; //File path you are getting from file chooser
String target = "./src"; //target place you want to patse
File locFile = new File(location);
File tarFile = new File(target);
backUpFolder.copyDirectory(locFile, tarFile);
} catch (IOException ex) {
Logger.getLogger(BackUpFolder.class.getName()).log(Level.SEVERE, null, ex);
}
}
}

Start by taking a look at Basic I/O, which explains the basics of Input/OutputStreams and Readers and Writers, which are used to read/write bytes of data from a source to a destination.
If you're using Java 7 or over, you should also take a look at Copying a File or Directory which is part of newer Files and Paths API, which you can find more information about at File I/O (Featuring NIO.2)

Related

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());
}```

Java File.renamTo not working

I have made the code which renames all the jpg files in a directory from 1 to n (number of files)..
if there were let say 50 jpg files that after running the program all the files are renamed to 1.jpg ,2.jpg and so on till 50.jpg
But i am facing the problem if I manually rename the file let say 50.jpg to aaa.jpg then again running the program doesn't rename that file
I have wasted one day to resove that issue
Kindly help me
Code:
public class Renaming {
private static String path; // string for storing the path
public static void main(String[] args) {
FileReader fileReader = null; // filereader for opening the file
BufferedReader bufferedReader = null; // buffered reader for buffering the data of file
try{
fileReader = new FileReader("input.txt"); // making the filereader object and paasing the file name
bufferedReader = new BufferedReader(fileReader); //making the buffered Reader object
path=bufferedReader.readLine();
fileReader.close();
bufferedReader.close();
}
catch (FileNotFoundException e) { // Exception when file is not found
e.printStackTrace();
}
catch (IOException e) { // IOException
e.printStackTrace();
}
finally {
File directory=new File(path);
File[] files= directory.listFiles(); // Storing the all the files in Array
int file_counter=1;
for(int file_no=0;file_no<files.length;file_no++){
String Extension=getFileExtension(files[file_no]); //getting the filw extension
if (files[file_no].isFile() && (Extension .equals("jpg")|| Extension.equals("JPG"))){ // checking that if file is of jpg type then apply renaming // checking thaat if it is file
File new_file = new File(path+"\\"+files[file_no].getName()); //making the new file
new_file.renameTo(new File(path+"\\"+String.valueOf(file_no+1)+".jpg")); //Renaming the file
System.out.println(new_file.toString());
file_counter++; // incrementing the file counter
}
}
}
}
private static String getFileExtension(File file) { //utility function for getting the file extension
String name = file.getName();
try {
return name.substring(name.lastIndexOf(".") + 1); // gettingf the extension name after .
} catch (Exception e) {
return "";
}
}`
first of all, you should use the path separator / . It's work on Windows, Linux and Mac OS.
This is my version of your problem to rename all files into a folder provide. Hope this will help you. I use last JDK version to speed up and reduce the code.
public class App {
private String path = null;
public static int index = 1;
public App(String path){
if (Files.isDirectory(Paths.get( path ))) {
this.path = path;
}
}
public void rename() throws IOException{
if ( this.path != null){
Files.list(Paths.get( this.path ))
.forEach( f ->
{
String fileName = f.getFileName().toString();
String extension = fileName.replaceAll("^.*\\.([^.]+)$", "$1");
try {
Files.move( f ,Paths.get( this.path + "/" + App.index + "." + extension));
App.index++;
} catch (IOException e) {
e.printStackTrace();
}
}
);
}
}
public static void main(String[] args) throws IOException {
App app = new App("c:/Temp/");
app.rename();
}
}

How to copy file from one location to another location?

I want to copy a file from one location to another location in Java. What is the best way to do this?
Here is what I have so far:
import java.io.File;
import java.io.FilenameFilter;
import java.util.ArrayList;
import java.util.List;
public class TestArrayList {
public static void main(String[] args) {
File f = new File(
"D:\\CBSE_Demo\\Demo_original\\fscommand\\contentplayer\\config");
List<String>temp=new ArrayList<String>();
temp.add(0, "N33");
temp.add(1, "N1417");
temp.add(2, "N331");
File[] matchingFiles = null;
for(final String temp1: temp){
matchingFiles = f.listFiles(new FilenameFilter() {
public boolean accept(File dir, String name) {
return name.startsWith(temp1);
}
});
System.out.println("size>>--"+matchingFiles.length);
}
}
}
This does not copy the file, what is the best way to do this?
You can use this (or any variant):
Files.copy(src, dst, StandardCopyOption.REPLACE_EXISTING);
Also, I'd recommend using File.separator or / instead of \\ to make it compliant across multiple OS, question/answer on this available here.
Since you're not sure how to temporarily store files, take a look at ArrayList:
List<File> files = new ArrayList();
files.add(foundFile);
To move a List of files into a single directory:
List<File> files = ...;
String path = "C:/destination/";
for(File file : files) {
Files.copy(file.toPath(),
(new File(path + file.getName())).toPath(),
StandardCopyOption.REPLACE_EXISTING);
}
Update:
see also
https://stackoverflow.com/a/67179064/1847899
Using Stream
private static void copyFileUsingStream(File source, File dest) throws IOException {
InputStream is = null;
OutputStream os = null;
try {
is = new FileInputStream(source);
os = new FileOutputStream(dest);
byte[] buffer = new byte[1024];
int length;
while ((length = is.read(buffer)) > 0) {
os.write(buffer, 0, length);
}
} finally {
is.close();
os.close();
}
}
Using Channel
private static void copyFileUsingChannel(File source, File dest) throws IOException {
FileChannel sourceChannel = null;
FileChannel destChannel = null;
try {
sourceChannel = new FileInputStream(source).getChannel();
destChannel = new FileOutputStream(dest).getChannel();
destChannel.transferFrom(sourceChannel, 0, sourceChannel.size());
}finally{
sourceChannel.close();
destChannel.close();
}
}
Using Apache Commons IO lib:
private static void copyFileUsingApacheCommonsIO(File source, File dest) throws IOException {
FileUtils.copyFile(source, dest);
}
Using Java SE 7 Files class:
private static void copyFileUsingJava7Files(File source, File dest) throws IOException {
Files.copy(source.toPath(), dest.toPath());
}
Or try Googles Guava :
https://github.com/google/guava
docs:
https://guava.dev/releases/snapshot-jre/api/docs/com/google/common/io/Files.html
Use the New Java File classes in Java >=7.
Create the below method and import the necessary libs.
public static void copyFile( File from, File to ) throws IOException {
Files.copy( from.toPath(), to.toPath() );
}
Use the created method as below within main:
File dirFrom = new File(fileFrom);
File dirTo = new File(fileTo);
try {
copyFile(dirFrom, dirTo);
} catch (IOException ex) {
Logger.getLogger(TestJava8.class.getName()).log(Level.SEVERE, null, ex);
}
NB:- fileFrom is the file that you want to copy to a new file fileTo in a different folder.
Credits - #Scott: Standard concise way to copy a file in Java?
public static void copyFile(File oldLocation, File newLocation) throws IOException {
if ( oldLocation.exists( )) {
BufferedInputStream reader = new BufferedInputStream( new FileInputStream(oldLocation) );
BufferedOutputStream writer = new BufferedOutputStream( new FileOutputStream(newLocation, false));
try {
byte[] buff = new byte[8192];
int numChars;
while ( (numChars = reader.read( buff, 0, buff.length ) ) != -1) {
writer.write( buff, 0, numChars );
}
} catch( IOException ex ) {
throw new IOException("IOException when transferring " + oldLocation.getPath() + " to " + newLocation.getPath());
} finally {
try {
if ( reader != null ){
writer.close();
reader.close();
}
} catch( IOException ex ){
Log.e(TAG, "Error closing files when transferring " + oldLocation.getPath() + " to " + newLocation.getPath() );
}
}
} else {
throw new IOException("Old location does not exist when transferring " + oldLocation.getPath() + " to " + newLocation.getPath() );
}
}
Copy a file from one location to another location means,need to copy the whole content to another location.Files.copy(Path source, Path target, CopyOption... options) throws IOException this method expects source location which is original file location and target location which is a new folder location with destination same type file(as original).
Either Target location needs to exist in our system otherwise we need to create a folder location and then in that folder location we need to create a file with the same name as original filename.Then using copy function we can easily copy a file from one location to other.
public static void main(String[] args) throws IOException {
String destFolderPath = "D:/TestFile/abc";
String fileName = "pqr.xlsx";
String sourceFilePath= "D:/TestFile/xyz.xlsx";
File f = new File(destFolderPath);
if(f.mkdir()){
System.out.println("Directory created!!!!");
}
else {
System.out.println("Directory Exists!!!!");
}
f= new File(destFolderPath,fileName);
if(f.createNewFile()) {
System.out.println("File Created!!!!");
} else {
System.out.println("File exists!!!!");
}
Files.copy(Paths.get(sourceFilePath), Paths.get(destFolderPath, fileName),REPLACE_EXISTING);
System.out.println("Copy done!!!!!!!!!!!!!!");
}
You can do it with the Java 8 Streaming API, PrintWriter and the Files API
try (PrintWriter pw = new PrintWriter(new File("destination-path"), StandardCharsets.UTF_8)) {
Files.readAllLines(Path.of("src/test/resources/source-file.something"), StandardCharsets.UTF_8)
.forEach(pw::println);
}
If you want to modify the content on-the-fly while copying, check out this link for the extended example https://overflowed.dev/blog/copy-file-and-modify-with-java-streams/
I modified one of the answers to make it a bit more efficient.
public void copy(){
InputStream in = null;
try {
in = new FileInputStream(Files);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
try {
OutputStream out = new FileOutputStream();
try {
// Transfer bytes from in to out
byte[] buf = new byte[1024];
while (true) {
int len = 0;
try {
if (!((len = in.read(buf)) > 0)) break;
} catch (IOException e) {
e.printStackTrace();
}
try {
out.write(buf, 0, len);
} catch (IOException e) {
e.printStackTrace();
}
}
} finally {
try {
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
} finally {
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
private void moveFile() {
copy();
File dir = getFilesDir();
File file = new File(dir, "my_filename");
boolean deleted = file.delete();
}
Files.exists()
Files.createDirectory()
Files.copy()
Overwriting Existing Files:
Files.move()
Files.delete()
Files.walkFileTree()
enter link description here
You can use
FileUtils.copy(sourceFile, destinationFile);
https://commons.apache.org/proper/commons-io/apidocs/org/apache/commons/io/FileUtils.html

Copying children files of a source to a destination in Java

I'm trying to make a program that copies a directory's children, and I can't label all the specific names because they vary throughout each folder. Here's the code I have, but if the source is "C:\src" and the output is "C:\dst" it'll create the folder "C:\dst\src(children files)", but I want to make "C:\dst(children files)". Can anyone help?
public static void copy(File source, File destination) throws IOException {
if (source == null) {
throw new NullPointerException("Null Source");
}
if (destination == null) {
throw new NullPointerException("Null Destination");
}
if (source.isDirectory()) {
copyDirectory(source, destination);
} else {
copyFile(source, destination);
}
}
//converts to location
public static void copyDirectory(File source, File destination) throws IOException {
copyDirectory(source, destination, null);
}
public static void copyDirectory(File source, File destination, FileFilter filter) throws IOException {
File nextDirectory = new File(destination, source.getName());
if (!nextDirectory.exists() && !nextDirectory.mkdirs()) {// create the directory if necessary...
Object[] filler = {nextDirectory.getAbsolutePath()};
String message = "Dir Copy Failed";
throw new IOException(message);
}
File[] files = source.listFiles();
for (int n = 0; n < files.length; ++n) {// and then all the items below the directory...
if (filter == null || filter.accept(files[n])) {
if (files[n].isDirectory()) {
copyDirectory(files[n], nextDirectory, filter);
} else {
copyFile(files[n], nextDirectory);
}
}
}
}
public static void copyFile(File source, File destination) throws IOException {
// what we really want to do is create a file with the same name in that dir
if (destination.isDirectory()) {
destination = new File(destination, source.getName());
}
FileInputStream input = new FileInputStream(source);
copyFile(input, destination);
}
public static void copyFile(InputStream input, File destination) throws IOException {
OutputStream output = null;
try {
output = new FileOutputStream(destination);
byte[] buffer = new byte[1024];
int bytesRead = input.read(buffer);
while (bytesRead >= 0) {
output.write(buffer, 0, bytesRead);
bytesRead = input.read(buffer);
}
} catch (Exception e) {
//
} finally {
input.close();
output.close();
}
input = null;
output = null;
}
Replace
if (source.isDirectory()) {
copyDirectory(source, destination);
} else {
copyFile(source, destination);
}
By
if (source.isDirectory()) {
for (File child : source.listFiles()) {
if (child.isDirectory()) {
copyDirectory(child, destination);
} else {
copyFile(child, destination);
}
}
} else {
copyFile(source, destination);
}
use getParentFile() to get the parent directory:
if (source.isDirectory()) {
copyDirectory(source, destination.getParentFile());
} else {
copyFile(source, destination.getParentFile());
}
You can do everything here in one line using commons-io library :
FileUtils.copyDirectory(src, dest);
see :
http://commons.apache.org/io/api-1.4/org/apache/commons/io/FileUtils.html#copyDirectory%28java.io.File,%20java.io.File%29
jar file : http://mvnrepository.com/artifact/commons-io/commons-io/2.4
Try this one. copying whole files in a folder from source to destination.
import java.io.*;
public class copydir
{
public static void main(String args[])
{
File srcFolder = new File("E://Paresh/programs/test");
File destFolder = new File("D://paresh");
if(!srcFolder.exists())
{
System.out.println("Directory does not exist.");
//just exit
System.exit(0);
}
else{
try{
copyDirectory(srcFolder,destFolder);
}
catch(IOException e)
{
e.printStackTrace();
//error, just exit
System.exit(0);
}
}
System.out.println("Done");
}
public static void copyDirectory(File src , File target) throws IOException
{
if (src.isDirectory())
{
if (!target.exists())
{
target.mkdir();
}
String[] children = src.list();
for (int i=0; i<children.length; i++)
{
copyDirectory(new File(src, children[i]),new File(target, children[i]));
}
}
// if Directory exists then only files copy
else
{
InputStream in = new FileInputStream(src);
OutputStream out = new FileOutputStream(target);
// Copy the bits from instream to outstream
byte[] buf = new byte[1024];
int len;
while ((len = in.read(buf)) > 0)
{
out.write(buf, 0, len);
}
in.close();
out.close();
}
}
}

zip4j zipping for files and folders in java

I wish to create a zip program in Java, which zip files and folders let say structure like this -
folder-one/
folder-one/one.txt
folder-one/two.mp3
folder-one/three.jpg
folder-two/
folder-two/four.doc
folder-two/five.rtf
folder-two/folder-three/
folder-two/folder-three/six.txt
I used zip4j open source, I have collected all the files (with absolute path) in one list then given it to zip but it is zipping files only as in my.zip -
one.txt
two.mp3
three.jpg
four.doc
five.rtf
six.txt
How can I preserve same structure on zipping and unzipping as it was on local earlier. Please suggest if any other open source can help me to zip/unzip in same structure files and folders like other windows zip programs.
Code is below --
public class CreateZipWithOutputStreams {
ArrayList filesToAdd = new ArrayList();
public void CreateZipWithOutputStreams(String sAbsolutePath) {
ZipOutputStream outputStream = null;
InputStream inputStream = null;
try {
ArrayList arrLocal = exploredFolder(sAbsolutePath);
outputStream = new ZipOutputStream(new FileOutputStream(new File("c:\\ZipTest\\CreateZipFileWithOutputStreams.zip")));
ZipParameters parameters = new ZipParameters();
parameters.setCompressionMethod(Zip4jConstants.COMP_DEFLATE);
parameters.setCompressionLevel(Zip4jConstants.DEFLATE_LEVEL_NORMAL);
parameters.setEncryptFiles(true);
parameters.setEncryptionMethod(Zip4jConstants.ENC_METHOD_AES);
parameters.setAesKeyStrength(Zip4jConstants.AES_STRENGTH_256);
parameters.setPassword("neelam");
for (int i = 0; i < arrLocal.size(); i++) {
File file = (File) arrLocal.get(i);
outputStream.putNextEntry(file, parameters);
if (file.isDirectory()) {
outputStream.closeEntry();
continue;
}
inputStream = new FileInputStream(file);
byte[] readBuff = new byte[4096];
int readLen = -1;
while ((readLen = inputStream.read(readBuff)) != -1) {
outputStream.write(readBuff, 0, readLen);
}
outputStream.closeEntry();
inputStream.close();
}
outputStream.finish();
} catch (Exception e) {
e.printStackTrace();
} finally {
if (outputStream != null) {
try {
outputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (inputStream != null) {
try {
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
public ArrayList exploredFolder(String sAbsolutePath) {
File[] sfiles;
File fsSelectedPath = new File(sAbsolutePath);
sfiles = fsSelectedPath.listFiles();
if (sfiles == null) {
return null;
}
for (int j = 0; j < sfiles.length; j++) {
File f = sfiles[j];
if (f.isDirectory() == true) {
exploredFolder(f.getAbsolutePath());
} else {
filesToAdd.add(f);
}
}
return filesToAdd;
}
public static void main(String[] args) {
new CreateZipWithOutputStreams().CreateZipWithOutputStreams("c:\\ZipTest");
}
}
Thanks!
Okay so first the code that is attached is supposed to work the way it is because the exploredFolder(String absolutePath) method is returning the "files to add" which in turn is being used by the CreateZipWithOutputStreams() method to create a single layered(flat) zip file.
What needs to be done is looping over the individual folders and keep adding them to the ZipOutputStream.
Please go through the link below and you will find the code snippet and detailed explaination.
Let me know if that helps!
http://www.java-forums.org/blogs/java-io/973-how-work-zip-files-java.html

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