How to delete the contents of a text file without deleting

Question

I want to copy the contents of file 'A' to file 'B'. after copying is complete, I want to clear the contents of file "A" and want to write on it from the very beginning. I can not delete the file "A", because it is associated with some other task.

I managed to copy the contents using the java file API (readLine ()), but I don’t know how to clear the contents of the file and set the file pointer to the beginning of the file.

Answer 1

Just print an empty line in the file:

PrintWriter writer = new PrintWriter(file); writer.print(""); writer.close(); 

Answer 2

I do not believe that you even need to write an empty line to a file.

 PrintWriter pw = new PrintWriter("filepath.txt"); pw.close(); 

Answer 3

You want the setLength () method in the RandomAccessFile class.

Answer 4

Just don’t write anything!

 FileOutputStream writer = new FileOutputStream("file.txt"); writer.write(("").getBytes()); writer.close(); 

Answer 5

One insert for trimming:

 FileChannel.open(Paths.get("/home/user/file/to/truncate"), StandardOpenOption.WRITE).truncate(0).close(); 

Additional information is available in the Java documentation: https://docs.oracle.com/javase/7/docs/api/java/nio/channels/FileChannel.html

Answer 6

After copying from A to B, open file A again to write the mode, and then write an empty line to it

Answer 7

Just write:

 FileOutputStream writer = new FileOutputStream("file.txt"); 

Answer 8

How about below:

 File temp = new File("<your file name>"); if (temp.exists()) { RandomAccessFile raf = new RandomAccessFile(temp, "rw"); raf.setLength(0); } 

Answer 9

One of the best companions for java is Apache Projects and please refer to it. To work with files, you can refer to the Commons IO project.

Below one line code will help us make the file empty.

 FileUtils.write(new File("/your/file/path"), "") 

Answer 10

Write a blank line to the file, clean and close. Make sure the file writer is not in add mode. I think this was supposed to do the trick.

Answer 11

If you do not need to use the author, then the shortest and cleanest way to do this will be as follows:

 new FileWriter("/path/to/your/file.txt").close(); 

Answer 12

you can use

 FileWriter fw = new FileWriter(/*your file path*/); PrintWriter pw = new PrintWriter(fw); pw.write(""); pw.flush(); pw.close(); 

Do not forget to use

 FileWriter fw = new FileWriter(/*your file path*/,true); 

True in the constructor constructor allows you to add.

Answer 13

 FileOutputStream fos = openFileOutput("/*file name like --> one.txt*/", MODE_PRIVATE); FileWriter fw = new FileWriter(fos.getFD()); fw.write(""); 

Answer 14

With Try-with-Resources Writer will be automatically closed:

 import org.apache.commons.lang3.StringUtils; final File file = new File("SomeFile"); try (PrintWriter writer = new PrintWriter(file)) { writer.print(StringUtils.EMPTY); } // here we can be sure that writer will be closed automatically 

Answer 15

using: New Java 7 NIO library, try

  if(!Files.exists(filePath.getParent())) { Files.createDirectory(filePath.getParent()); } if(!Files.exists(filePath)) { Files.createFile(filePath); } // Empty the file content writer = Files.newBufferedWriter(filePath); writer.write(""); writer.flush(); 

The above code checks if Directoty exists, if it does not create a directory, checks if the file exists, yes, it writes an empty line and clears the buffer, at the end you get a writer that points to an empty file

Answer 16

All you have to do is open the file in truncate mode. Any class of Java files will automatically do this for you.

Answer 17

you can write a generic method as (its too late, but below code will help you / others)

 public static FileInputStream getFile(File fileImport) throws IOException { FileInputStream fileStream = null; try { PrintWriter writer = new PrintWriter(fileImport); writer.print(StringUtils.EMPTY); fileStream = new FileInputStream(fileImport); } catch (Exception ex) { ex.printStackTrace(); } finally { writer.close(); } return fileStream; }