CODEWITHSUNDEEP
javaregex
Ramesh
Ramesh

Reputation: 2337

Replacing an \u with \\u in a string using java

I am trying to replace an \u in a url.

C:\testing\bing\utest\university.txt

when i use url=url.replaceAll("\\u", "\\\\u"); I am getting the below error May i know how to replace the \u with \u or escaping the \u

java.util.regex.PatternSyntaxException: Illegal Unicode escape sequence near index 2
\u

Upvotes: 0

Views: 1174

Answers (3)

TheLostMind
TheLostMind

Reputation: 36304

You have to use it like this : url=url.replaceAll("\\\\u", "\\\\\\\\u"); . The first argument to replaceAll() is a regex and the second argument is a string.

Why? :

If you look at the code of matcher.appendReplacement() which is called from replaceAll(), you have : 

 while (cursor < replacement.length()) {
            char nextChar = replacement.charAt(cursor);
            if (nextChar == '\\') {

So, each \ will have to be considered which leads to 4 *2 =8 \s in the code

Upvotes: 3

jaypi
jaypi

Reputation: 223

url.replaceAll("\\\\u", "\\\\\\\\u")

Will produce:

C:\testing\bing\\utest\\university.txt

Upvotes: 2

anubhava
anubhava

Reputation: 785631

You can actually ditch the regex and use non-regex method String#replace for this:

String repl = "C:\\testing\\bing\\utest\\university.txt".replace("\\u", "\\\\u");
//=> C:\testing\bing\\utest\\university.txt

Upvotes: 5

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