使用正则表达式替换子字符串

Question

I have a string which contains many <xxx> values.

I want to retrive the value inside <> , do some manipulation and re-insert the new value into the string.

What I did is

input = This is <abc_d> a sample <ea1_j> input <lmk_02> string
while(input.matches(".*<.+[\S][^<]>.*"))
{
   value = input.substring(input.indexOf("<") + 1, input.indexOf(">"));
   //calculate manipulatedValue from value
   input = input.replaceFirst("<.+>", manipulatedValue);
}

but after the first iteration, value contains abc_d> a sample <ea1_j> input <lmk_02 . I believe indexOf(">") will give the first index of ">". Where did I go wrong?

Answer 1

This is a slightly easier way of accomplishing what you are trying to do:

String input = "This is <abc_d> a sample <ea1_j> input <lmk_02> string";
Matcher matcher = Pattern.compile("<([^>]*)>").matcher(input);
StringBuffer sb = new StringBuffer();
while(matcher.find()) {
    matcher.appendReplacement(sb, manipulateValue(matcher.group(1)));
}
matcher.appendTail(sb);
System.out.println(sb.toString());

Answer 2

This is a good use case for the appendReplacement and appendTail idiom:

Pattern p = Pattern.compile("<([^>]+)>");
Matcher m = p.matcher(input);
StringBuffer out = new StringBuffer():
while(m.find()) {
  String value = m.group(1);
  // calculate manipulatedValue
  m.appendReplacement(out, Matcher.quoteReplacement(manipulatedValue));
}
m.appendTail(out);

Answer 3

尝试对正则表达式使用转义字符\\\\ 。