如何在Java中从回车符中修剪字符串

Question

I have a string:

\n\n\n\Mytext is here\n new line \n\n

with an unknown amount of \\n at the beginning and at the end.

How can I trim this string to

Mytext is here\n new line 

in an elegant way?

I know I could code this with my own function. But, perhaps there is a simple solution?

Answer 1

Trim it, using trim method of String which " Returns a copy of the string, with leading and trailing whitespace omitted. "

Note that it Returns a copy of the string and doesn't edit the String

myString.trim()

Null Strings

As @rmertins said, this is not "null safe", meaning if your String is null it will throw a NullPointerException so if your String can be null , wrap it.

if (myString != null)
{
  String newTrimmedString = myString.trim();
}

Importing an entire library to do this one task like @rmertins said (ie StringUtils from apache commons) is just overkill I'd say. I would also say it's bad practice to pass around null objects anyhow and null String objects suggests bad design.

Answer 2

String.trim() will trim away white space at the beginning and end. That would probably be the quickest way. If you need to retain other white spaces and only want to remove the \\n , I think you would have to replace them manually.

You could try something along the lines of

myString = myString.replace("^(\\n)*","").replace("(\\n)*$","");

(I have not tried this code.)

Answer 3

Check out the String.trim() method

String foo = "\n\n  \n\t actual Value\t\n \n ";
System.out.println(foo.trim()); //prints "actual Value"

About as simple and elegant as it gets. Keep in mind, though, that this will not only trim newline characters, but tabs, spaces, etc. as well.

Answer 4

如果您的字符串可能为null ，则可能要使用StringUtils.trim() - String.trim()的null安全版本。