Inserting a Java string in another string without concatenation? [duplicate]

Answer 1

It may be done by some template-libaries. But beware, Strings are immutable in Java. So in every case at some low level the concatenation will be done.

Answer 2

What you want is called String interpolation. It is not possible in Java, although JRuby, Groovy and probably other JVM languages do that.

---

Edit: as for elegance, you can use a StringBuffer or check the other poster's solution. But at the low level, this will always be concatenation, as the other posters said.

Answer 3

I would use a StringBuffer.. it's a common practise when you are dealing with strings. It may seem a bit when you see it for the first time, but you'll get quickly used to it..

String test = new StringBuffer("text goes here ").append(value1).append(" more text").toString();

Strings are immutable thus a new instance is created after every concatenation. This can cause performance issues when used in loops.

StringBuffer is mutable version of String - that means you can create one, modify it as you want and you have still only one instance. When desired you can get a String representation of the StringBuffer by calling it's toString() method.

Answer 4

The problem is not if this is an elegant way or not. The idea behind using a template system may be that you put your template in a normal text file and don't have to change java code if you change your message (or think about i18ln).

Answer 5

You can use this free library. It gives you sprintf like functionality. Or use String.format static method provided you use Java 5 or newer.

Answer 6

You'll always have to use some form of concatenation for this (assuming value1 isn't a constant like you show here).

The way you've written it will implicitly construct a StringBuilder and use it to concatenate the strings. Another method is String.format(String, Object...)¹, which is analogous to sprintf from C. But even with format(), you can't avoid concatenation.

¹ Yes, I know the anchor link is broken.