how to delete the content of text file without deleting itself

user_651545 0
Viewed 292048

I want to copy the content of file 'A' to file 'B'. after the copying is done I want to clear the content of file 'A' and want to write on it from its beginning. I can't delete file 'A' as it is related to some other task.

I was able to copy the content using java's file API(readLine() ), but don't know how to clear the content of file and set the file pointer to the beginning of the file.

android java
17 Answers

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 exist if not creates the directory, checks if file exists is yes it writes empty string and flushes the buffer, in the end yo get the writer pointing to empty file

user_32099210

All you have to do is open file in truncate mode. Any Java file out class will automatically do that for you.

Admin1

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
user_93226200
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