Easy question

[JavaNoob]

Ok I am trying to write a program that when ran, will Println all the lines in a specific file (ss.txt). while println-ing, f textline is ever a certain name "william", it will also println "xxxxxxxx" (so that I can find that specific name when I look at the list ).

I run my program and it traverses the file and prints that lines correctly but it never does anything once it gets to the "william" name.

here is my code:

Code:

import java.io.*;
public class ReadFile
{
public static void main(String[] args)
{
try
{
FileReader file = new FileReader("data/ss.txt");
BufferedReader buffer=new BufferedReader (file);
String textline = null;
while((textline = buffer.readLine()) !=null)
System.out.println(textline);
if (textline = "William") System.out.println("xxxxxx");
buffer.close();

}
catch (IOException e) { System.out.println(e);}
}
}

Thanks
JN

[levent]

Quote:

if (textline = "William") System.out.println("xxxxxx");

There should be two equals sign there to compare the result.

More than that, for comparing strings, you should use equals method of String class!

[JavaNoob]

Levent, thanks for the quick response!
I will give that a try (though i may have tried that).
what is this "equals method of String class" (Keep in mind, I am relatively new to Java)?

Thanks
JN

[levent]

Check javadoc of String class.

You can write that line like this:

Code:

if (textline.equals("William")) System.out.println("xxxxxx");

[JavaNoob]

I tried the "textline.equals("william") and it still ran through the txt file without println-ing the "xxxxx" . At the end, it did say:
Exception in thread "main" java.lang.NullPointerException
at ReadFile.main(ReadFile.java:13)

line 13 is where it if command is.

any more ideas?

[JavaNoob]

do you think it's returning this argument because it's not finding anything named "william"?

also, is there a chance that it's looking for a string that is JUST william but it's not finding it because my string has a william and a last name associated to it?

[levent]

Code:

...
while((textline = buffer.readLine()) !=null)
System.out.println(textline);
if (textline.equals("William")) System.out.println("xxxxxx");
...

You should write those lines like this. I guess you will notice the difference.

Code:

...
while((textline = buffer.readLine()) !=null)
{
    System.out.println(textline);
    if (textline.equals("William")) System.out.println("xxxxxx");
}
...

[levent]

Quote:

also, is there a chance that it's looking for a string that is JUST william but it's not finding it because my string has a william and a last name associated to it?

Yes, it is looking for exactly "william" in a case sensitive way.

Read the javadoc i sent. There is a indexOf method there if you want to find all lines containing "william".

[JavaNoob]

Quote:

Originally Posted by JavaNoob;

also, is there a chance that it's looking for a string that is JUST william but it's not finding it because my string has a william and a last name associated to it?

I put that to the test, and made a line that only had the name william, and it still didn't work.

[levent]

Check my previous post: Easy question

[JavaNoob]

Perfect! That's what I was looking for!

Thanks again.


JN