我在将 ArrayLists 的内容写入文件时遇到问题

Question

So I wrote some code for a vocabulary trainer for my german class and want to write the content of my ArrayLists to a file. However it only writes the first of the 3 ArrayLists into the file when saving. Does anyone know what causes this, or better yet, how to fix it? Thanks for you help!

I have already reset all the ArrayLists and re-implemented the file it should write into, but nothing helped.

These are all just sequences of Code, not the whole program. It is over 400 lines Long so I didnt want to paste the whole thing. The Code runs flawlessly until I open the file I wrote into.

static ArrayList<String> vokabel = new ArrayList<String>();
static ArrayList<String> uebersetzung = new ArrayList<String>();
static ArrayList<Integer> kasten = new ArrayList<Integer>(); 

static void beenden() {
  for(int m = 0; m < groesse; m++) {
    String str = vokabel.get(m).toString();
    textWriter.write(str);
    textWriter.write(" ");
  }
  textWriter.close();
  textWriter.println();
  for(int n = 0; n < groesse; n++) {
    String str = uebersetzung.get(n).toString();
    textWriter.write(str);
    textWriter.write(" ");
  }
  textWriter.close();
  textWriter.println();
  for(int o = 0; o < groesse; o++) {
    String str = kasten.get(o).toString();
    textWriter.write(str);
    textWriter.write(" ");
  }
  textWriter.close();
  textWriter.println();

  System.exit(0);

}

I expect it to write the content of all 3 ArrayLists into the file, though it didn't work up until now. This is what ends up in the file after entering 3 words with their translations and their corresponding case number. Only the words themselves make it into the file:

Hund Nein Hallo

Answer 1

The reason it only writes the first ArrayList into the file is because you're closing the TextWriter immediately after writing it (and when the TextWriter is closed, it doesn't write stuff). Just remove all the

textWriter.close();

lines, and then put just one right before System.exit(0) , and it should work properly.

Answer 2

You write all 3 lists one after the other. AND: Inbetween you close the writer! So you are "lucky" not to get an IOException.

I guess you would like the entries of the 3 lists together (vokabel + uebersetzung+ kasten). Therefore I suggest you create a class taking 3 fields with the information. Give this class a sensible toString() and simply write those objects one line at a time.

Ah and btw: Don't ever call System.exit! It makes your program unusable in a larger context and prevents proper cleanup of resources.

Answer 3

Use Flush.when you have text longer than buffer size it will not write.

System.IO.TextWriter writeFile = new StreamWriter("c:\\textwriter.txt");
writeFile.WriteLine("csharp.net-informations.com");
writeFile.Flush();
writeFile.Close();