Writing to an already existing file using FileWriter Java
Asked Answered
R

2

10

Is there anyway I can write to an already existing file using Filewriter

For example when the user clicks a submit button:

FileWriter writer = new FileWriter("myfile.csv");
writer.append("LastName");
writer.append(',');
writer.append("FirstName");
writer.append('/n');

writer.append(LastNameTextField.getText());
writer.append(',');
writer.append(FirstNameTextField.getText());

I want to be able to write new data into the already existing myfile.csv without having to recreate a brand new one every time

Rojas answered 9/6, 2010 at 10:57 Comment(1)
Do you want to append (write the new data at the end of the old), or replace (write the new data over the top of the old)? I would have thought append (as did the answerers so far), but "write new data into" sounds more like replace.Conall
A
23

Yeah. Use the constructor like this:

FileWriter writer = new FileWriter("myfile.csv",true);
Ant answered 9/6, 2010 at 10:58 Comment(1)
@TwilightPonyInc. It's not quite pseudocode, it is the method declaration, but yeah! The code is ALWAYS much more useful!Ardeth
I
7
FileWriter

public FileWriter(File file,
                  boolean append)
           throws IOException

Constructs a FileWriter object given a File object. If the second argument is true, then bytes will be written to the end of the file rather than the beginning. 
Illsorted answered 9/6, 2010 at 10:58 Comment(0)

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