Java Cookbook

Trimming Blanks from the End of a String

Problem

You need to work on a string without regard for extra leading or trailing spaces a user may have typed.

Solution

Use the String class trim( ) method.

Discussion

Example 3-8 uses trim( ) to strip an arbitrary number of leading spaces and/or tabs from lines of Java source code in order to look for the characters //+ and //-. These are special (to me) Java comments I use to mark the parts of the programs in this book that I want to include in the printed copy.

Example 3-8. GetMark.java (trimming and comparing strings)

/** the default starting mark. */
public final String startMark = "//+";
/** the default ending mark. */
public final String endMark = "//-";
/** True if we are currently inside marks. */
protected boolean printing = false;

       try {
        String inputLine;

        while ((inputLine = is.readLine(  )) != null) {
                if (inputLine.trim(  ).equals(startMark)) {
                    printing = true;
                } else if (inputLine.trim(  ).equals(endMark)) {
                    printing = false;
                } else if (printing)
                    System.out.println(inputLine);
            }
            is.close(  );
        } catch (IOException e) {
           // not shown
        }
    }