Can't replace string with regex in java

Question

I'm trying to replace a string occurrence in a query like this:

SELECT * FROM DB WHERE AGE = 3 and NAME = 'VALUE'

I'm using this regex: NAME\s*=\s*'[A-Z]+' that works fine here

This is how I've tried in Java:

query.replaceAll("NAME\s*=\s*'[A-Z]+'", replacementString); // Gives me Invalid escape sequence message
query.replaceAll("NAME\\s*=\\s*'[A-Z]+'", replacementString); 

Pattern pattern = Pattern.compile("NAME*= *'[A-Z]*'");
query.replaceAll(pattern.pattern(), replacementString);

Pattern pattern2 = Pattern.compile("NAME\\s*=\\s*'[A-Z]*'");                
query.replaceAll(pattern2.pattern(), replacementString);

None of this work.

How can I replace the NAME = 'VALUE' occurrence?

Escape your backslashes: `\\s*` to fix the "invalid escape sequence" error. — Andy Turner, Apr 06 '16 at 14:39
Precausion: make sure "VALUE" never contains `'`, otherwise simple regex won't suffice. — bezmax, Apr 06 '16 at 14:40
The problem is with the `query.replaceAll(pattern2.pattern(), replacementString);` - you need to assign the value to a string variable. — Wiktor Stribiżew, Apr 06 '16 at 14:40
`"NAME\\s*=\\s*'[A-Z]*'"` is ok to use. You can also use `"NAME\\s*=\\s*'[^']*'"`. If you need to use a compiled pattern, use it with the Matcher, see [demo](http://ideone.com/frn3iQ). But that is just an enhancement. Your main problem is with the modified value assignment. — Wiktor Stribiżew, Apr 06 '16 at 14:43
**No, it works after you assign the value: see [this demo](https://ideone.com/ArkWDm)** — Wiktor Stribiżew, Apr 06 '16 at 14:52

Andy Turner · Accepted Answer · 2016-04-06T14:47:43.697

1

Java strings are immutable.

You need to assign the result of the replaceAll call back to the string:

query = query.replaceAll(...);

edited Apr 06 '16 at 14:47

answered Apr 06 '16 at 14:41

Andy Turner

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Why post an evident answer? http://stackoverflow.com/questions/3611635/java-regex-replaceall-does-not-replace-string – Wiktor Stribiżew Apr 06 '16 at 14:41

score 0 · Answer 2 · 2016-04-06T14:40:42.037

0

Try this,

query.replaceAll("NAME\\s*=\\s*'[A-Z]+'", replacementString); 
query.replaceAll("NAME\\s*=\\s*'[A-Z]+'", replacementString);

And then in your pattern,

Pattern pattern2 = Pattern.compile("NAME\\s*=\\s*'[A-Z]*'");                
query.replaceAll(pattern2.pattern(), replacementString);

edited Apr 06 '16 at 14:40

answered Apr 06 '16 at 14:39

What if OP wants to first compile the pattern? – Wiktor Stribiżew Apr 06 '16 at 14:40
Already tried, it doesn't work – Wilder Pereira Apr 06 '16 at 14:40

Can't replace string with regex in java

2 Answers2