无法将任何内容写入文件

Question

I am trying to write to file

try
{
    PrintWriter fileout = new PrintWriter("./src/javaapplication1/test.dat");

    for(int i=0;i<10;i++)
    {
         fileout.println(i);
    }
 }
 catch (IOException e)
 {
      System.out.println("File cannot be created");

 }

However nothing gets written to the file , I am expecting

1
2
3
4
5
6
7
8
9

What is wrong with the way i am writing to the file ??

Answer 1

You haven't closed the writer. It's almost certainly just buffered all the data.

You should always close IO streams etc. If you're using Java 7+, you can use a try-with-resources statement:

try (PrintWriter fileout = new PrintWriter("./src/javaapplication1/test.dat")) {
    for (int i = 0; i < 10; i++) {
        fileout.println(i);
    }
} catch (IOException e) {
    // Don't just swallow the exception - use that information!
    System.out.println("Error writing file: " + e);
}

If you're using an earlier version of Java, you should use a finally block to close the writer whether an exception is thrown or not.