Question

I have a problem and a question with using Strings.

The problem I am having is reading a line in a text file. Let’s say in my .txt file I have the word ‘hello’ and I am simply trying to validate that the user inputs the same thing.

The .txt file simply has the word ‘hello’

Here is the code.

String fileWord;

File filename = fileOpen.getSelectedFile(); // Open the .txt file
FileReader filereader = new FileReader(filename);
BufferedReader inputFile = new BufferedReader(filereader);

String input = JOptionPane.showInputDialog("Say hello");
fileWord = inputFile.readLine();

if (input == fileWord)
     System.out.println("They match!");

However, this doesn’t work. I did a System.out.println on both input and fileWord and they appear to be the same, but they’re not as the if() statement doesn’t work.

Another question I have is if in a .txt file I have on one line ‘hello goodbye’ how do I read one word on a line at a time? For example, if the user inputs ‘hello’ then it finds it in the text file and returns ‘goodbye’.

EDIT
I’ve gotten further in my program and have run into another issue. Whenever a user inputs a word, if it doesn’t find the word in the file, it is suppose to write the word to a new file. In my program, I’m using a loop to search through the file to find the word. When I input a word that doesn’t exist in the file, I get an exception error and the program closes. I can’t quite figure out where and how I figure out that the word isn’t in the file.

while (!input.equals(fileWord))
{
     fileWord = inputFile.readLine();
     String[] wordSplit = englishWord.split("\\s+", 2);
     fileWord = wordSplit[0];
     fileWord2 = wordSplit[1];
}

System.out.println("The opposite of " + fileWord + " is " + fileWord2);

This example would find “hello” in the text file and output “goodbye” and that works fine. But, if I put some random word as the input and it won’t find it, what do I do to move on and proceed with adding it into a new file? I can figure out how to write to a file, I think…I just can’t get out of the loop correctly without an exception.

Answer 1

Use equals() to compare strings and not ==:

if (input.equals(fileWord))

As to your second question, the easiest way is to read the entire line, then split() it. That’ll give you a two-element array of Strings. You can use the first element for comparison and return the second element if there’s a match:

String[] words = line.split("\\s+", 2);
// words[0] will contain "hello"
// words[1] will contain "goodbye"