What is an efficient way to parse a String in Java?

Question

How should I parse the following String using Java to extract the file path?

? stands for any number of random charaters

_ stands for any number of white spaces (no new line)

?[LoadFile]_file_=_"foo/bar/baz.xml"?

Example:

10:52:21.212 [LoadFile] file = "foo/bar/baz.xml"

should extract foo/bar/baz.xml

Answer 1

java.util.regex is your friend.

Answer 2

String regex = ".*\\[LoadFile\\]\\s+file\\s+=\\s+\"([^\"].+)\".*";

Matcher m = Pattern.compile(regex).matcher(inputString);
if (!m.find()) 
    System.out.println("No match found.");
else
    String result = m.group(1);

The String in result should be your file path. (assuming I didn't make any mistakes)

You should take a look at the Pattern class for some regular expression help. They can be a very powerful string manipulation tool.

Answer 3

You could make the regular expression a bit shorter than jinguy's. Basically just the RHS without the "'s.

    String regex = ".* = \"(.*)\"";

Answer 4

While regular expressions are nice and all, you can also use class java.util.StringTokenizer to do the job. The advantage is a more human-friendly code.

StringTokenizer tokenizer = new StringTokenizer(inputString, "\"");
tokenizer.nextElement();
String path = tokenizer.nextElement();

And there you go.