Properly format a Java String to fit into a JavaScript variable

Question

I'm pretty new to Java, let's say I have a String containing multiple things (quotes, double quotes, new lines etc...)

I want to "encode" that string so I can output it safely into a JavaScript snippet like:

var test = '<%= myJavaString %>';

So if there's any special characters into myJavaString like newlines, ex:

String myJavaString = "hello\neveryone\nof the\nworld";

I don't want my JavaScript source to look like:

var test = 'hello
everyone
of the
world';

Any built-in functions!?

Thanks!

Just a note: the appearance of the rendered javascript source is really immaterial - if your string has newlines and you want the newlines passed to javascript, that is what it will look like. Who's going to be looking at your rendered source? Rendered javascript is about function, not form. Just sayin' — Chris Baker
– Chris Baker, Commented Aug 26, 2011 at 16:12
@Chris - Actually, it does matter. Javascript doesn't handle multi-line strings properly, unless you add a forward slash to the end of each line. — Sam Dufel
– Sam Dufel, Commented Aug 26, 2011 at 16:15
Theres no built-in functions for what your looking for. Which inevitably leads to the next question, is there sample code out there already that does the same thing. — Perception
– Perception, Commented Aug 26, 2011 at 16:20
@Chris/Sam Dufel: Also, all kinds of characters the JavaScript interpreter might not like, that's why they should be encoded in the string literal... — Mike Gleason jr Couturier
– Mike Gleason jr Couturier, Commented Aug 26, 2011 at 16:52
Yeah, I was not thinking that through, my comment is incorrect in that regard. — Chris Baker
– Chris Baker, Commented Aug 26, 2011 at 17:52

JB Nizet · Accepted Answer · 2011-08-26 16:24:58Z

4

Look at Apache commons-lang StringEscapeUtils class. It has a escapeEcmaScript method which will escape the newline chars to \n, but also the tab, quote and double-quote chars.

answered Aug 26, 2011 at 16:24

JB Nizet

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3 Comments

bobince Over a year ago

+1. A JSON encoder is another possibility, if you've already got one in your project.

Mike Gleason jr Couturier Over a year ago

I'm using Spring... maybe it got one!?

JB Nizet Over a year ago

I'm not aware of such a utility method in Spring. But using Spring doesn't prevent you from using commons-lang.

Alexis King · Accepted Answer · 2011-08-26 16:18:23Z

0

Well, I'm not sure if there are any built-in methods you can use, but it probably wouldn't be too hard to write one. Remember, you just need to replace \n with \\n to change it from a "special" character into just a \ and an n.

You may want to use regular expressions. Sadly, I'm not the best at regular expressions, so I may not be the best person to help you.

answered Aug 26, 2011 at 16:18

Alexis King

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1 Comment

Mike Gleason jr Couturier Over a year ago

Thanks for trying to help, I don't know who downvoted you up I upvoted to square things out. Even thought I accepted the other answer, thanks.

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