How to replace a plus character using Java's String.replaceAll method

Question

What\'s the correct regex for a plus character (+) as the first argument (i.e. the string to replace) to Java\'s replaceAll method in the String class? I can\'t

Answer 1

Say you want to replace - with \\\-, use:

 text.replaceAll("-", "\\\\\\\\-");

Answer 2

You'll need to escape the + with a \ and because \ is itself a special character in Java strings you'll need to escape it with another \.

So your regex string will be defined as "\\+" in Java code.

I.e. this example:

String test = "ABCD+EFGH";
test = test.replaceAll("\\+", "-");
System.out.println(test);

Answer 3

If you want a simple string find-and-replace (i.e. you don't need regex), it may be simpler to use the StringUtils from Apache Commons, which would allow you to write:

mystr = StringUtils.replace(mystr, "+", "plus");

Answer 4

when in doubt, let java do the work for you:

myStr.replaceAll(Pattern.quote("+"), replaceStr);

Answer 5

How about replacing multiple ‘+’ with an undefined amount of repeats?

Example: test+test+test+1234

(+) or [+] seem to pick on a single literal character but on repeats.

Answer 6

String str="Hello+Hello";   
str=str.replaceAll("\\+","-");
System.out.println(str);

OR

String str="Hello+Hello";   
str=str.replace(Pattern.quote(str),"_");
System.out.println(str);