Java outputting to text file?

Question

So I am having troubles printing to output. I understand the concept, but when it comes to this problem its kinda weird. I've tried different print lines and all of them give me different results from the console window. I'm still trying different things, but im starting to run out of ideas. Thanks and much appreciated !

This is what I want the expected output to be.

1
1, 2, 3, 4

When I try println it does this for output.println(data[0]);

1
, 2, 3, 4

when I do a regular print it does this

1, 2, 3, 4

This is the text file print method`

    public class JavaApplication1 {

  static int[] Array(int[] data) {

      int size = 1;
      if (data !=null) {
          size = 1 +data.length;
      }
      return new int [size];
  }

  private static int[] addToArray(int[] data, int x) {
      int[] array2 = Array(data);
      if(data !=null) {
          System.arraycopy(data,0,array2,0,data.length);
      }
      array2[array2.length - 1] = x;
      return array2;
  }
  private int[] data;

  public JavaApplication1 (int[] data, int x) {
      this.data = addToArray(data, x);      
  }
  public void printall() {
      System.out.print(data[0]);
      for (int i = 1; i < data.length; i++) {
          System.out.printf(", %d", data[i]);

      }
      System.out.println();
  } public void text() {
    try {
           PrintWriter output =  new PrintWriter("test.txt");
           output.print(data[0]);
           for (int i = 1; i < data.length; i++) {
               output.printf( ", %d", data[i]);
               output.flush();
           }
    } catch (Exception ex) {

    }


  }


    public static void main(String[] args) {
        int[] in = {1,2,3};
        int[] test = {1,2,3};

        int l = 4;
        int x = 4;

        JavaApplication1 a = new JavaApplication1(null, 1);
        a.printall();
        JavaApplication1 b = new JavaApplication1(in, x);
        b.printall();


        JavaApplication1 c = new JavaApplication1(null, 1);
        c.text();
        JavaApplication1 d = new JavaApplication1(test, l);
        d.text();




    }

}

@bkail I am just having problems printing to text file, and would like some help. — madauewo, May 19 '15 at 05:06
From what I understand, you want your output in a text file, instead of the console? — Soumitri Pattnaik, May 19 '15 at 05:07
Are you not getting any out put in your text file ? @madauewo — Soumitri Pattnaik, May 19 '15 at 05:15
@SoumitriPattnaik Yes I am , but the format is weird,look the 2 after the 1st one, that happens when I output it to the text file. — madauewo, May 19 '15 at 05:17
Uses bufferedwriter http://stackoverflow.com/questions/14503595/write-file-using-bufferedwriter-in-java — 0x2B, May 19 '15 at 05:24
@madauewo find my answer below, I ran that, it works, Thanks :) — Soumitri Pattnaik, May 19 '15 at 05:27
`This is what I want the expected output to be: ...` - that is exactly what I get on the **console** when I run your program. In the text **file**, only the second line is shown, since you are **overwriting** the text file when you run your `text()` method the second time. — Andreas Fester, May 19 '15 at 05:29

The Well · Answer 1 · 2015-05-19T05:34:24.963

0

Try this:

PrintWriter output =  new PrintWriter("test.txt");
output.println(data[0]);      //this is where you call the println
for (int i = 0; i < data.length; i++) {
    output.printf( ", %d", data[i]);
    output.flush();
}

edited May 19 '15 at 05:34

answered May 19 '15 at 05:24

The Well

876
1
9
22

This won't work. First you have a misspelling 'print', it should be 'printf'. Second it does not produce the output he wants – Soumitri Pattnaik May 19 '15 at 05:29
@Soumitri Pattnaik, PrintWriter has a print method. Here's the documentation: https://docs.oracle.com/javase/7/docs/api/java/io/PrintWriter.html – The Well May 19 '15 at 05:30
I know there is a print method. But you have called it wrong, look at all the definitions of print, it takes one argument, but you have two,. – Soumitri Pattnaik May 19 '15 at 05:34
However, your code still does not produce the out put that he wants – Soumitri Pattnaik May 19 '15 at 05:36

Yu Yenkan · Answer 2 · 2015-05-19T05:33:50.913

0

try do in this way

public void text() {
    try {
       PrintWriter output =  new PrintWriter("test.txt");

       for (int i = 0; i < data.length; i++) {
           if(i > 0){
               output.print(",");
           }

           output.print(data[i]);
           output.flush();     
       }   
    } catch (Exception ex) {
    }
}

edited May 19 '15 at 05:33

answered May 19 '15 at 05:25

Yu Yenkan

745
1
9
32

score 0 · Accepted Answer · answered May 19 '15 at 05:25

Try this :

public void text() {
        try {
            PrintWriter output = new PrintWriter("test.txt");
            output.println(data[0]);
            for (int i = 0; i < data.length; i++) {
                if (i != (data.length - 1)) {
                    output.printf("%d, ", data[i]);
                } else {
                    output.printf("%d", data[i]);
                }
                output.flush();
            }
        } catch (Exception ex) {

        }

    }

@madauewo, what is the expected output of your code, if you replace values of test to `int[] test = {4,5,6};`? — Naman Gala, May 19 '15 at 06:42

score 0 · Answer 4 · answered May 19 '15 at 05:25

0

To make it a new line for each output loop it and add "\n" to each line you write or you can convert to string and edit String format to whatever you want. You can add a comma if you want

string.format()

answered May 19 '15 at 05:25

0x2B

91
9

score 0 · Answer 5 · edited May 23 '17 at 11:43

Cause of problem: In your code, everytime you call text(), you are replacing existing file, without updating or appending new data to it.

Refer this SO question. You can write printWriter as

PrintWriter output = new PrintWriter(new BufferedWriter(new FileWriter("test.txt", true)));

I have tested on local, Try this code.

public void text() {
    try {
        // Adding data to existing file without replacing it.
        PrintWriter output = new PrintWriter(new BufferedWriter(new FileWriter("test.txt", true)));
        output.print(data[0]);
        for (int i = 1; i < data.length; i++) {
            output.printf(", %d", data[i]);
        }
        output.print("\n"); // Added next line in the file
        output.flush();
        output.close(); // closing PrintWriter.
    } catch (Exception ex) {
        // log your exception.
    }
}

Java outputting to text file?

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