java - Iterating over the content of a text file line by line - is there a best practice? (vs. PMD's AssignmentInOperand)

Question

We have a Java Application that has a few modules that know to read text files. They do it quite simply with a code like this:

BufferedReader br = new BufferedReader(new FileReader(file));  
String line = null;  
while ((line = br.readLine()) != null)  
{  
   ... // do stuff to file here  
} 

I ran PMD on my project and got the 'AssignmentInOperand' violation on the while (...) line.

Is there a simpler way of doing this loop other than the obvious:

String line = br.readLine();  
while (line != null)  
{  
   ... // do stuff to file here  
   line = br.readLine();  
} 

Is this considered a better practice? (although we "duplicate" the line = br.readLine() code?)

Answer 1

I know is an old post but I just had the same need (almost) and I solve it using a LineIterator from FileUtils in Apache Commons. From their javadoc:

LineIterator it = FileUtils.lineIterator(file, "UTF-8");
try {
    while (it.hasNext()) {
    String line = it.nextLine();
    // do something with line
    }
} finally {
    it.close();
}

Check the documentation: http://commons.apache.org/proper/commons-io/javadocs/api-release/org/apache/commons/io/LineIterator.html