CODEWITHSUNDEEP
javafileprintingtext-files
kevorski
kevorski

Reputation: 836

Opening and Writing to file Java

I'm currently stuck on a spot in my code. I need to write data to a text file, I have sorts going and they are taking the time that each sort takes to complete and then puts them into a txt file that I can then use to create graphs. Problem is that I just get one line after I run the program. I can't get it to keep each result.

public static void resultsToFile(String sort, double seconds, File file)
{
    try (PrintWriter out = new PrintWriter(new FileWriter(file)))
    {
        out.write(sort + "\t"); 
        out.write(seconds + " seconds\n");
        out.flush();
        out.close();

    }catch (IOException e)
    {
        e.printStackTrace();
    }   
}

This is what I have so far for my writing to files method. Any help would be greatly appreciated!

Upvotes: 0

Views: 226

Answers (2)

MByD
MByD

Reputation: 137272

As HovercraftFullOfEals mentioned, you open the file for each line, and this is a big performance overhead.

Yet the problem you see is because you don't open the file to append to it, but to write to it from the beginning. To append to the file, open it using the constructor FileWriter(File,boolean):

try (PrintWriter out = new PrintWriter(new FileWriter(file, true)))

Upvotes: 3

Hovercraft Full Of Eels
Hovercraft Full Of Eels

Reputation: 285415

You're creating a new PrintWriter object each time you write a line of results to the file and thus over-writing any previously existing File that held the previous line of data. Why not create your PrintWriter once in the class, and then close it when you're done writing all of the data to file?

Upvotes: 3

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