You need this instead:
if(s.contains("+"))
contains()
method of String
class does not take regular expression as a parameter, it takes normal text.
EDIT:
String s = "ddjdjdj+kfkfkf";
if(s.contains("+"))
{
String parts[] = s.split("\\+");
System.out.print(parts[0]);
}
OUTPUT:
ddjdjdj