What's the best way to build a string of delimited items in Java?

Question

While working in a Java app, I recently needed to assemble a comma-delimited list of values to pass to another web service without knowing how many elements there would be i

Answer 1

Your approach is not too bad, but you should use a StringBuffer instead of using the + sign. The + has the big disadvantage that a new String instance is being created for each single operation. The longer your string gets, the bigger the overhead. So using a StringBuffer should be the fastest way:

public StringBuffer appendWithDelimiter( StringBuffer original, String addition, String delimiter ) {
        if ( original == null ) {
                StringBuffer buffer = new StringBuffer();
                buffer.append(addition);
                return buffer;
        } else {
                buffer.append(delimiter);
                buffer.append(addition);
                return original;
        }
}

After you have finished creating your string simply call toString() on the returned StringBuffer.