Replace String pattern in Java

Question

I have the following string

"value=\"\\d{4}((((0[1-9])|(1[0-2]))((0[1-9])|([12]\\d)|(3[01]))?)?|(\\-(((0[1-9])|(1[0-2]))(\\-((0[1-9])|([12]\\d)|(3[01])))?)?)?)d{4}"

There I want to replace all the occurrences of

"{" with NCHAR(0x7B)
"}" with NCHAR(0x7D). 

An the content in-between "{ }" should remain unchanged:

Ex: \\d{4} after replacing -> NCHAR(0x7B) 4 NCHAR(0x7D).

Is there a way to do this using Regular Expressions in Java?.

Anyway, this can be done processing the whole string using string operations.

• Aurelien Ribon: Are you sure '\\d{4}' should not become '\\d NCHAR(0x7B) 4 NCHAR(0x7D)'?

Answer 1

I do not see any need for a regexp in your issue, since you want to replace every '{' and every '}'. Is that what you mean? Or do you want to replace these character only when then are behind a '\d'?

theString = theString.replace("{", "NCHAR(0x7B)");
theString = theString.replace("}", "NCHAR(0x7D)");

EDIT:

Sample code

public class QuickTest {
 public static void main(String args[]) {
 String theString = "toto \\d{123} 456 789";
 theString = theString.replace("{", "NCHAR(0x7B)");
 theString = theString.replace("}", "NCHAR(0x7D)");
 System.out.println(theString);
 }
}

Result

$> java QuickTest
toto \dNCHAR(0x7B)123NCHAR(0x7D) 456 789

• Aurelien Ribon: @Barun I just tested it, it works, see my edit. What version of Java do you use? Are you really really sure you did not used replaceAll()? replace() does not use the regexp engine, so your exception does not make any sense.

Answer 2

I agree with Aurélien Ribon, however if you want to use regex you could do it like this,

String data = "value=\"\\d{4}((((0[1-9])|(1[0-2]))((0[1-9])|([12]\\d)|(3[01]))?)?|(\\-(((0[1-9])|(1[0-2]))(\\-((0[1-9])|([12]\\d)|(3[01])))?)?)?)d{4}";
data = data.replaceAll("\\{", "NCHAR(0x7B)").replaceAll("\\}","NCHAR(0x7D)");

Answer 3

Since you need to replace all occurrences of { and }, you can use replaceAll()

String theString = "\\d{4}((((0[1-9])|(1[0-2]))((0[1-9])|([12]\\d)|(3[01]))?)?|(\\-(((0[1-9])|(1[0-2]))(\\-((0[1-9])|([12]\\d)|(3[01])))?)?)?)d{4}";
theString = theString.replaceAll("{", "NCHAR(0x7B)");
theString = theString.replaceAll("}", "NCHAR(0x7D)");

Answer 4

 String val = "\\d{4}((((0[1-9])|(1[0-2]))((0[1-9])|([12]\\d)|(3[01]))?)?|(\\-(((0[1-9])|(1[0-2]))(\\-((0[1-9])|([12]\\d)|(3[01])))?)?)?)d{4}";
 val = val.replace("{", "NCHAR(0x7B)");
 val = val.replace("}", " NCHAR(0x7D)"); 
 System.out.println("value::"+val);
 ------------------------------------------------------------------------

Answer 5

String text = "\\\\d{4}((((0[1-9])|(1[0-2]))((0[1-9])|([12]\\d)|(3[01]))?)?|(\\-(((0[1-9])|(1[0-2]))(\\-((0[1-9])|([12]\\d)|(3[01])))?)?)?)d{4}";
 text = text.replaceAll("[{]", "NCHAR(0x7B)");
 text = text.replaceAll("[}]", "NCHAR(0x7D)");
 System.out.println(text);