在java中替换字符串中的单词

Question

String[] operatorList = { "name", "first_name", "last_name", "city" };
String originalString = "city=Houston^ORlast_name=Cervantsz^ORfirst_name=John^name=don";
for (String opElement : operatorList) {
    if (originalString.contains(opElement)) {
        String tempStr = originalString.replace(opElement, "user." + opElement);
        originalString = tempStr;
    }
}
System.out.println("originalString " + originalString);

Output:

user.city=Houston^ORlast_user.name=Cervantsz^ORfirst_user.name=John^user.name=don

When i am trying to replace name with "user.name" at that time name from "last_name" is replaced with "last_user.name" and first_name with first_user.name

But i want replace "name" with "user.name" and "last_name" with "user.last_name" and "first_name" with "user.first_name".

Any help appreciated.

Answer 1

You can add prefix all key and control that key. Example

String[] operatorList = {"name", "first_name", "last_name", "city"};
    String originalString = "city=Houston^ORlast_name=Cervantsz^ORfirst_name=John^ORname=don";
    for (String opElement : operatorList) {
        if (originalString.contains("^OR"+opElement)) {
            String tempStr = originalString.replace(opElement, "user." + opElement);
            originalString = tempStr;
        }
    }
    System.out.println("originalString " + originalString);

Answer 2

If the values you are trying to change are always unique and generated (meaning they are always in the same order), you can simply put your operators in the same order and use replaceLast() instead.

A more complete solution would be to determine how the string is constructed. Do all the values have a ^ in front of them? Is OR generated for the same values or is it to indicate optional values?. So in the end, what allows you to split the string properly. Then you can use a Regex to use the surrounding characters.

I would format the string to make sure the splitters are constant (all "^OR" become "@@%!!" and all remaining "^" become "%!!") so all replaced strings start with !!. Then I would reformat the string to the original format using the remaining "@@%" or "%" :

String[] operatorList = { "name", "first_name", "last_name", "city" };
String originalString = "city=Houston^ORlast_name=Cervantsz^ORfirst_name=John^name=don";

originalString = originalString.replaceAll("\\^OR", "@@%!!");
originalString = originalString.replaceAll("\\^", "%!!");
  //the order is important here

for (String opElement : operatorList) {
    if (originalString.startsWith(opElement)) {
        originalString = originalString.replaceFirst(opElement, "user." + opElement);
    }

    originalString = originalString.replaceAll("!!" + opElement, "user." + opElement);
      // no need for an other alternative here because replaceAll returns the
      // String as is if it does not find the first parameter in the String.
}

originalString = originalString.replaceAll("@@%", "^OR");
originalString = originalString.replaceAll("%", "^");
  // the order here is also important

outputs : "user.city=Houston^ORuser.last_name=Cervantsz^ORuser.first_name=John^user.name=don"

Answer 3

If all keypairs need prefix "user.", I would like to split originalString first.

In Java8

String originalString = "city=Houston^ORlast_name=Cervantsz^ORfirst_name=John^name=don";
String[] params = originalString.split("\\^");

String result = String.join("^", Arrays.stream(params)
    .map(param -> param.startsWith("OR") ? "ORuser." + param.substring(2) : "user." + param)
    .collect(Collectors.toList()));

System.out.println(result);

It can also be changed to for loop type.

Answer 4

You may use a quick search and replace with an alternation based pattern created dynamically from the search words only when they are preceded with a word boundary or ^ + OR / AND /etc. operators and followed with a word boundary. Note that this solution assumes the search words only consist of word chars (letters, digits or _ ):

String[] operatorList = { "name", "first_name", "last_name", "city" };
// assuming operators only consist of word chars
String pat = "(\\b|\\^(?:OR|AND)?)(" + String.join("|", operatorList) + ")\\b";
String originalString = "city=Houston^ORlast_name=Cervantsz^ORfirst_name=John^name=don";
originalString = originalString.replaceAll(pat, "$1user.$2");
System.out.println(originalString);
// => user.city=Houston^ORuser.last_name=Cervantsz^ORuser.first_name=John^user.name=don

See the Java demo online

The regex will look like

(\b|\^(?:OR|AND)?)(name|first_name|last_name|city)\b

See the regex demo .

Details

• (\\b|\\^(?:OR|AND)?) - Group 1: a word boundary \\b or a ^ symbol and an optional substring, OR or AND (you may add more here after | )
• (name|first_name|last_name|city) - Group 2: any of the search words
• \\b - a trailing word boundary.

The $1 in the replacement pattern inserts the contents of Group 1 and $2 does the same with Group 2 contents.