Java：使用trim（）后得到不正确的string.length（）

Question

I have the string "22" and I'm getting 3 as length;

I used .trim()

What else could be a reason for this?

Answer 1

You should be giving us code that demonstrates the problem, but my guess is you did something like this:

String str = "22 ";
str.trim();
System.out.println(str.length());

But str.trim() doesn't change str (as Strings are immutable). Instead it returns a new String trimmed. So you need something like this:

String str = "22 ";
str = str.trim();
System.out.println(str.length());

Answer 2

Try this:

System.out.println(java.util.Arrays.toString(theString.toCharArray()));

This dumps the char[] version of the String , so we can perhaps see if it contains anything funny.

Answer 3

since i found a reason while formulating the question, im gonna answer myself..

If the string was created by .substring or split, the whole string is saved plus the position and length of the substring.

this apparently cant be trimmed (was " 22")