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How to copy lines from a text file to another text file? [duplicate]

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

Unable to recover correct file extension after creating .gz through GZipOutputStream

I have the contents I want to write to a file saved in Strings in my Java program. I need o write them to a .txt file and then compress them into a .gz archive. I'm able to do all of this, but when I extract the file from the .gz archive, the extracted file no longer bear's the .txt file extension.
This is my code below:
private void fillFileBody(OutputStream outputStream) throws IOException {
Scanner scanner = new Scanner(new ByteArrayInputStream(this.fileBody.getBytes()));
while(scanner.hasNextLine()){
outputStream.write((scanner.nextLine() + "\n").getBytes());
}
scanner.close();
}
public void writeFileContentsToDisk(){
GZIPOutputStream gZipOutStream = null;
FileOutputStream initialTxtFileOutStream = null;
FileInputStream initialTxtFileInStream = null;
String txtFile = this.fileName + ".txt";
try {
initialTxtFileOutStream = new FileOutputStream(txtFile);
initialTxtFileOutStream.write((this.fileHeader).getBytes());
fillFileBody(initialTxtFileOutStream);
initialTxtFileOutStream.write(this.fileTrailer.getBytes());
initialTxtFileInStream = new FileInputStream(txtFile);
gZipOutStream = new GZIPOutputStream(new FileOutputStream(this.fileName + ".gz"));
byte[] buffer = new byte[1024];
int length;
while ((length = initialTxtFileInStream.read(buffer)) > 0) {
gZipOutStream.write(buffer, 0, length);
}
} catch (Exception e) {
LOGGER.error("Error writing file: " + Logger.getStackTrace(e));
}
try {
gZipOutStream.close();
initialTxtFileOutStream.close();
initialTxtFileInStream.close();
} catch (IOException e) {
LOGGER.warn("Error closing i/o streams involved in writing file: " + Logger.getStackTrace(e));
}
}

I wrote the sample code below and used x.c as input from my working directory. x.c.gz was the output file. I used gunzip on x.c.gz and it produced a file with the name x.c and so it seemed to work fine.
package compress;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.GZIPOutputStream;
/**
*
* #author srikanthn
*/
public class Compress {
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
compressFile(args[0]);
}
public static void compressFile(String file){
GZIPOutputStream gZipOutStream = null;
FileInputStream initialTxtFileInStream = null;
String txtFile = file;
try {
initialTxtFileInStream = new FileInputStream(txtFile);
gZipOutStream = new GZIPOutputStream(new FileOutputStream(txtFile+ ".gz"));
byte[] buffer = new byte[1024];
int length;
while ((length = initialTxtFileInStream.read(buffer)) > 0) {
gZipOutStream.write(buffer, 0, length);
}
} catch (IOException e) {
System.out.println("Error writing file: " + e.getStackTrace());
}
try {
gZipOutStream.close();
initialTxtFileInStream.close();
} catch (IOException e) {
System.out.println("Error closing i/o streams involved in writing file: " + e.getStackTrace());
}
}
}

How to download a file and get the path location locally

I have a URL i.e http://downloadplugins.verify.com/Windows/SubAngle.exe .
If I paste it on the tab and press enter then the file (SubAngle.exe) is getting downloaded and saved in the download folder. This is a manual process. But it can be done with java code.
I wrote the code for getting the absolute path with the help of the file name i.e SubAngle.exe.
Requirement:- With the help of the URL file gets downloaded,Verify the file has been downloaded and returns the absolute path of the file.
where locfile is "http://downloadplugins.verify.com/Windows/SubAngle.exe"
public String downloadAndVerifyFile(String locfile) {
File fileLocation = new File(locfile);
File fileLocation1 = new File(fileLocation.getName());
String fileLocationPath = null;
if(fileLocation.exists()){
fileLocationPath = fileLocation1.getAbsolutePath();
}
else{
throw new FileNotFoundException("File with name "+locFile+" may not exits at the location");
}
return fileLocationPath;
}

easy and general function that im using:
import org.apache.commons.io.FileUtils;
public static void downLoadFile(String fromFile, String toFile) throws MalformedURLException, IOException {
try {
FileUtils.copyURLToFile(new URL(fromFile), new File(toFile), 60000, 60000);
} catch (FileNotFoundException e) {
e.printStackTrace();
System.out.println("exception on: downLoadFile() function: " + e.getMessage());
}
}

Instead of writing this huge code, go for Apache's commons.io
Try this:
URL ipURL = new URL("inputURL");
File opFile = new File("outputFile");
FileUtils.copyURLToFile(ipURL, opFile);

Code to DownloadFile from URL
import java.net.*;
import java.io.*;
public class DownloadFile {
public static void main(String[] args) throws IOException {
InputStream in = null;
FileOutputStream out = null;
try {
// URL("http://downloadplugins.verify.com/Windows/SubAngle.exe");
System.out.println("Starting download");
long t1 = System.currentTimeMillis();
URL url = new URL(args[0]);
// Open the input and out files for the streams
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
in = conn.getInputStream();
out = new FileOutputStream("YourFile.exe");
// Read data into buffer and then write to the output file
byte[] buffer = new byte[8192];
int bytesRead;
while ((bytesRead = in.read(buffer)) != -1) {
out.write(buffer, 0, bytesRead);
}
long t2 = System.currentTimeMillis();
System.out.println("Time for download & save file in millis:"+(t2-t1));
} catch (Exception e) {
// Display or throw the error
System.out.println("Erorr while execting the program: "
+ e.getMessage());
} finally {
// Close the resources correctly
if (in != null) {
in.close();
}
if (out != null) {
out.close();
}
}
}
}
Configure the value of fileName properly to know where the file is getting stored.
Source: http://www.devmanuals.com/tutorials/java/corejava/files/java-read-large-file-efficiently.html
The source was modified to replace local file with http URL
Output:
java DownloadFile http://download.springsource.com/release/TOOLS/update/3.7.1.RELEASE/e4.5/springsource-tool-suite-3.7.1.RELEASE-e4.5.1-updatesite.zip
Starting download
Time for download & save file in millis:100184

Set file path on FTPClient

i'm new to java programming and am using Apache commons net ftp to upload text files to my ftp server.
however, it seems that i can only upload the files on the same directory as my program .. when i set the file path to something like that : "C:\Users\Packard\Documents\ProjectsJava\FugeLessons\outputFile.txt" , it throws no errors, but when i check the ftp, there is nothing, like it has not been uploaded .
here is the code i'm using :
import org.apache.commons.net.ftp.FTPClient;
import java.io.FileInputStream;
import java.io.IOException;
public class ftp{
private final String host = "ftp.address.com";
private final String user = "user";
private final String pass = "pass";
public static void main(String[] args) {
ftp client = new ftp();
client.FtpUpload("C:\\Users\\Packard\\Documents\\ProjectsJava\\FugeLessons\\outputFile.txt");
}
public String FtpUpload(String filename){
FTPClient client = new FTPClient();
FileInputStream fis = null;
try {
client.connect(this.host);
client.login(this.user, this.pass);
fis = new FileInputStream(filename);
client.storeFile(filename, fis);
client.logout();
System.out.println("File " + filename + "\t uploaded successfully!");
} catch(IOException e){
error error = new error();
error.setVisible(true);
e.printStackTrace();
} finally {
try {
if ( fis != null) {
fis.close();
}
client.disconnect();
} catch(IOException e){
e.printStackTrace();
}
}
String ret = "success";
return ret;
}
}
what am i doing wrong ?
Thanks for your help!

You can use ftpClient method getReplyString() to get the error message. Below code can help.
boolean isSendSucces = ftpClient.storeFile(fileName, input );
if( isSendSuccess )
{
System.out.println("Sent File: " + fileName);
}
else
{
System.out.println("Problem is sending File: " + ftpClient.getReplyString());
}

How to close and delete file in Java

I have written code that should be saved file in the local directory, create zip of that file, send email and delete both files (original and zip), So this is my code:
Method wich send email
public void sendEmail(Properties emailProperties, InputStream inputStream, HttpServletRequest request) throws UnsupportedEncodingException {
MimeMessage mimeMessage = mailSender.createMimeMessage();
try {
MimeMessageHelper mimeMessageHelper = new MimeMessageHelper(mimeMessage, true);
try {
mimeMessageHelper.setFrom(from, personal);
} catch (UnsupportedEncodingException e) {
LOGGER.error(e.getMessage());
throw new SequelException(e.getMessage());
}
mimeMessageHelper.setTo(recipients);
mimeMessageHelper.setSubject(emailProperties.getProperty(PARAM_TITLE));
String message = emailProperties.getProperty(PARAM_EMLMSG);
mimeMessageHelper.setText(message);
InputStreamSource inputStreamSource = null;
if (inputStream != null) {
inputStreamSource = new ByteArrayResource(IOUtils.toByteArray(inputStream));
}
String compressType = COMPRESS_TYPE_ZIP;
String fileName = getAttachFilenameExtension(object, format);
Path filePath = Paths.get(StrUtils.getProperty("temp.email.files.path") + "\\" + fileName);
tempFile = saveTempFile(inputStreamSource.getInputStream(), filePath);
if (tempFile.length() > 0) {
inputStreamSource = compressFile(tempFile, filePath.toString(), compressType);
fileName = StringUtils.substring(fileName, 0, StringUtils.lastIndexOf(fileName, ".")+1) + compressType;
}
mimeMessageHelper.addAttachment(fileName, inputStreamSource);
mailSender.send(mimeMessage);
} catch (MessagingException | IOException e) {
LOGGER.error(e.getMessage());
throw new SequelException(e.getMessage());
} finally {
List<File> files = (List<File>) FileUtils.listFiles(tempFile.getParentFile(), new WildcardFileFilter(
FilenameUtils.removeExtension(tempFile.getName()) + "*"), null);
for (File file : files) {
try {
FileUtils.forceDelete(file);
} catch (IOException e) {
LOGGER.error(e.getMessage());
}
}
}
}
Save file in directory:
private File saveTempFile(InputStream inputStream, Path filePath) throws IOException {
Files.deleteIfExists(filePath);
Files.copy(inputStream, filePath);
return new File(filePath.toString());
}
Compress file:
private InputStreamSource compressFile(File file, String filePath, String compressType) throws IOException {
InputStream is = ZipFile(file, filePath);
InputStreamSource inputStreamSource = new ByteArrayResource(IOUtils.toByteArray(is));
return inputStreamSource;
}
public InputStream ZipFile(File file, String filePath) {
String zipArchiveFileName = StringUtils.substring(filePath, 0, filePath.lastIndexOf(".") + 1) + COMPRESS_TYPE_ZIP;
try (ZipArchiveOutputStream zipOutput = new ZipArchiveOutputStream(new File(zipArchiveFileName));) {
ZipArchiveEntry entry = new ZipArchiveEntry(StringUtils.overlay(file.getName(), "",
StringUtils.lastIndexOf(file.getName(), "_"), StringUtils.lastIndexOf(file.getName(), ".")));
zipOutput.putArchiveEntry(entry);
try (FileInputStream in = new FileInputStream(file);) {
byte[] b = new byte[1024];
int count = 0;
while ((count = in.read(b)) > 0) {
zipOutput.write(b, 0, count);
}
zipOutput.closeArchiveEntry();
}
InputStream is = new FileInputStream(zipArchiveFileName);
return is;
} catch (IOException e) {
LOGGER.error("An error occurred while trying to compress file to zip", e);
throw new SequelException(e.getMessage());
}
}
So the problem is when I try to delete files but zip file does not delete.
I am using Apache commons compress for zipping.
Can you help what's wrong?

For me this code is working perfectly. After compressing you may be trying to delete it without the extension(for eg .7z here).
public static void main(String[] args) {
File file = new File("C:\\Users\\kh1784\\Desktop\\Remote.7z");
file.delete();
if(!file.exists())
System.out.println("Sucessfully deleted the file");
}
Output:-
Sucessfully deleted the file