替换两个字符串和边界词之间的字符串

Question

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I want to replace string variable text between two words and replace the boundary words themselves. Similar to this question, however I want to replace between &firstString and &endString with newText .

Replace a String between two Strings

Input:

abcd&firstString={variableText}&endStringxyz

Output:

abcdnewTextxyz

I could just do two str.replaceAll(&firstString) and str.replaceAll(&secondString) . However, is it possible to do in one line of code changing maybe this code solution?

String newstr = str.replaceAll("(&firstString=)[^&]*(&endString=)", "$1foo$2");

Answer 1

The question is really confusing but I think I have got it based on the other answer.

You want to replace &firstString={XYZ}&endString with the value of a XYZ String variable?

First of all, in Java, one cannot reference a variable using a String that stores the variable name (Java is statically typed). To counteract this, you can have a HashMap that stores the 'variable' names as the keys and the replacement String as the value.

So, using your example we have:

String in = "abcd&firstString={variableText}&endStringxyz";

and you want to replace variableText with "newText" .

So, we can do this:

Map<String, String> replacementMap = new HashMap<>(){{
  put("variableText", "newText"); // replace "variableText" with "newText"
  put("foo", "bar"); // replace "foo" with "bar"
}};

We can then declare a utility method for replacement (slightly modified code gotten from here ):

private static final Pattern replaceTextPattern = Pattern.compile("&firstString=\\{.*?\\}&endString");

public static String replaceText(String input, Map<String, String> replacementMap){
    StringBuilder sb = new StringBuilder();
    Matcher matcher = replaceTextPattern.matcher(input);
    while(matcher.find()){
        String match = matcher.group();
        String key = match.substring(
                    match.indexOf('{')+1,
                    match.lastIndexOf('}')
        );
        String replacement = replacementMap.get(key);
            
        matcher.appendReplacement(sb, replacement);
    }
    matcher.appendTail(sb);
    return sb.toString();
}

And finally call the method:

System.out.println(replaceText(in, replacementMap)); // abcdnewTextxyz

It even works with multiple variables:

System.out.println(replaceText("abcd&firstString={variableText}&endStringxyz&firstString={foo}&endStringdef", replacementMap)); // abcdnewTextxyzbardef

Answer 2

String replacement = "newText";
String text = "abcd&firstString={currentText}&secondStringxyz";
String result = text.replaceAll("&firstString=\\{.*?\\}&secondString",replacement);

System.out.println(result);

prints

abcdnewTextxyz