The following code writes a string to a specific file.
String content = "Text To be written on a File";
File file = new File("c:/file.txt");
FileOutputStream foutput = new FileOutputStream(file);
if (!file.exists()) {
file.createNewFile();
}
byte[] c = content.getBytes();
foutput.write(c);
foutput.flush();
foutput.close();
I want to use this code in a Jbutton so every time the user clicks it, it writes the string to a NEW text file NOT OVERWRITE the existed one. I tried to do but I couldn't get the result.
Thank you in advance.
There's a couple of different ways you can get this result, it really depends on the application. The two easiest ways to do this would to be either:
Append the current timestamp to the file name
Use the File API to create a "temp file" in the directory, which is guarenteed to have a unique name
Option 1:
String baseDir = "c:/";
File newFile = new File(baseDir, "file_" + System.currentTimeMillis() + ".txt");
// do file IO logic here...
Option 2:
String baseDir = "c:/";
File newFile = File.createTempFile("file", ".txt", new File(baseDir));
// do file IO logic here...
If you want to write it to a new file, you have to create a new file. The name of the text file is always file.txt in your case.
Try this:
private int filecounter = 0; // this is the member of your class. Outside the function.
//inside your function
File file = new File("c:/file" + Integer.(filecounter).toString() + ".txt");
// you do something here.
filecounter++;
This way, your files will be stored as file0.txt, file1.txt etc.
Related
I want to upload files and save them into specific directory.And i am new to files concept.When i uploading files from my page they are saved in another directory(C:\Users\ROOTCP~1\AppData\Local\Temp\multipartBody989135345617811478asTemporaryFile) and not in specified directory.I am unable to set it.Please help me in finding a solution.For all help thanks in advance.
public static Result uploadHoFormsByHeadOffice() throws Exception {
Logger.info("#C HoForms -->> uploadHoFormsByHeadOffice() -->> ");
final String basePath = System.getenv("INVOICE_HOME");
play.mvc.Http.MultipartFormData body = request().body()
.asMultipartFormData(); // get Form Body
StringBuffer fileNameString = new StringBuffer(); // to save file path
// in DB
String formType = body.asFormUrlEncoded().get("formType")[0];// get formType from select Box
FilePart upFile = body.getFile("hoFiles");//get the file details
String fileName = upFile.getFilename();//get the file name
String contentType = upFile.getContentType();
File file = upFile.getFile();
//fileName = StringUtils.substringAfterLast(fileName, ".");
// path to Upload Files
File ftemp= new File(basePath +"HeadOfficeForms\\"+formType+"");
//File ftemp = new File(basePath + "//HeadOfficeForms//" + formType);
File f1 = new File(ftemp.getAbsolutePath());// play
ftemp.mkdirs();
file.setWritable(true);
file.setReadable(true);
f1.setWritable(true);
f1.setReadable(true);
//HoForm.create(fileName, new Date(), formType);
Logger.info("#C HoForms -->> uploadHoFormsByHeadOffice() <<-- Redirecting to Upload Page for Head Office");
return redirect(routes.HoForms.showHoFormUploadPage());
}
}
I really confused why the uploaded file is saved in this(C:\Users\ROOTCP~1\AppData\Local\Temp\multipartBody989135345617811478asTemporaryFile) path.
You're almost there.
File file = upFile.getFile(); is the temporary File you're getting through the form input. All you've got to do is move this file to your desired location by doing something like this: file.renameTo(ftemp).
Your problem in your code is that you're creating a bunch of files in memory ftemp and f1, but you never do anything with them (like writing them to the disk).
Also, I recommend you to clean up your code. A lot of it does nothing (aforementioned f1, also the block where you're doing the setWritable's). This will make debugging a lot easier.
I believe when the file is uploaded, it is stored in the system temporary folder as the name you've provided. It's up to you to copy that file to a name and location that you prefer. In your code you are creating the File object f1 which appears to be the location you want the file to end up in.
You need to do a file copy to copy the file from the temporary folder to the folder you want. Probably the easiest way is using the apache commons FileUtils class.
File fileDest = new File(f1, "myDestFileName.txt");
try {
FileUtils.copyFile(ftemp, fileDest);
}
catch(Exception ex) {
...
}
I am trying to have my app export a .csv file that can be picked up in the download APP. The way I am doing this is through fileoutput
I get remotedir By calling Environment.getExternalStorageDirectory().getAbsolutePath()
* Download CSV
*/
public static void downloadCSV(String filename, String remoteDir) throws Exception{
File dir = new File( remoteDir + "/download/");
dir.mkdirs();
//FileWriter f = new FileWriter("Download/" + filename + ".csv");
File fileObject = new File(dir, filename);
fileObject.delete();
fileObject.createNewFile();
ObjectOutputStream objectOut = null;
FileOutputStream stream = new FileOutputStream(fileObject);
objectOut = new ObjectOutputStream(new BufferedOutputStream(stream));
/* Irrelevant code */
String csv = Helper.getCSV(table.getColumnList(), view);
objectOut.writeChars(csv);
objectOut.close();
}
Whenever I test it on my phone(HTC One S) I don't see the file anywhere. I want my csv file to pop up in the Downloads app, but I'm not sure which directory that represents.
Thanks
You might have to scan the file with the MediaScanner before it will show up, at least that's how you'll be able to see it from your desktop for finding/debugging. See the MediaScanner docs for details.
i need some help with creating file
Im trying in the last hours to work with RandomAccessFile and try to achieve the next logic:
getting a file object
creating a temporary file with similar name (how do i make sure the temp file will be created in same place as the given original one?)
write to this file
replace the original file on the disk with the temporary one (should be in original filename).
I look for a simple code who does that preferring with RandomAccessFile
I just don't how to solve these few steps right..
edited:
Okay so ive attachted this part of code
my problem is that i can't understand what should be the right steps..
the file isn't being created and i don't know how to do that "switch"
File tempFile = null;
String[] fileArray = null;
RandomAccessFile rafTemp = null;
try {
fileArray = FileTools.splitFileNameAndExtension(this.file);
tempFile = File.createTempFile(fileArray[0], "." + fileArray[1],
this.file); // also tried in the 3rd parameter this.file.getParentFile() still not working.
rafTemp = new RandomAccessFile(tempFile, "rw");
rafTemp.writeBytes("temp file content");
tempFile.renameTo(this.file);
} catch (IOException ex) {
ex.printStackTrace();
} finally {
rafTemp.close();
}
try {
// Create temp file.
File temp = File.createTempFile("TempFileName", ".tmp", new File("/"));
// Delete temp file when program exits.
temp.deleteOnExit();
// Write to temp file
BufferedWriter out = new BufferedWriter(new FileWriter(temp));
out.write("Some temp file content");
out.close();
// Original file
File orig = new File("/orig.txt");
// Copy the contents from temp to original file
FileChannel src = new FileInputStream(temp).getChannel();
FileChannel dest = new FileOutputStream(orig).getChannel();
dest.transferFrom(src, 0, src.size());
} catch (IOException e) { // Handle exceptions here}
you can direct overwrite file. or do following
create file in same directory with diff name
delete old file
rename new file
I want to create a text file into that folder that I am creating here.
File dir = new File("crawl_html");
dir.mkdir();
String hash = MD5Util.md5Hex(url1.toString());
System.out.println("hash:-" + hash);
File file = new File(""+dir+"\""+hash+".txt");
But this code doesn't create the text file into that folder..Instead it makes the text file outside that folder..
One of java.io.File's constructors takes a parent directory. You can do this instead:
final File parentDir = new File("crawl_html");
parentDir.mkdir();
final String hash = "abc";
final String fileName = hash + ".txt";
final File file = new File(parentDir, fileName);
file.createNewFile(); // Creates file crawl_html/abc.txt
What you need is
File file = new File(dir, hash + ".txt");
The key here is the File(File parent, String child) constructor. It creates a file with the specified name under the provided parent directory (provided that directory exists, of course).
The line
new File(""+dir+"\""+hash+".txt");
makes a file named crawl_html"the_hash.txt, because \" inside a String literal is used to represent a double quote caracter, not a backslash. \\ must be used to represent a backslash.
Use the File constructor taking a File (directory) as the first argument, and a file name as a second argument:
new File(dir, hash + ".txt");
your path-delimiter seems off
try:
File file = new File ( "" + dir + "/" + hash + ".txt" );
I want to write a file results.txt to a specific directory on my machine (Z:\results to be precise). How do I go about specifying the directory to BufferedWriter/FileWriter?
Currently, it writes the file successfully but to the directory where my source code is located. Thanks
public void writefile(){
try{
Writer output = null;
File file = new File("results.txt");
output = new BufferedWriter(new FileWriter(file));
for(int i=0; i<100; i++){
//CODE TO FETCH RESULTS AND WRITE FILE
}
output.close();
System.out.println("File has been written");
}catch(Exception e){
System.out.println("Could not create file");
}
}
You should use the secondary constructor for File to specify the directory in which it is to be symbolically created. This is important because the answers that say to create a file by prepending the directory name to original name, are not as system independent as this method.
Sample code:
String dirName = /* something to pull specified dir from input */;
String fileName = "test.txt";
File dir = new File (dirName);
File actualFile = new File (dir, fileName);
/* rest is the same */
Hope it helps.
Use:
File file = new File("Z:\\results\\results.txt");
You need to double the backslashes in Windows because the backslash character itself is an escape in Java literal strings.
For POSIX system such as Linux, just use the default file path without doubling the forward slash. this is because forward slash is not a escape character in Java.
File file = new File("/home/userName/Documents/results.txt");
Just put the full directory location in the File object.
File file = new File("z:\\results.txt");
The best practice is using File.separator in the paths.