CODEWITHSUNDEEP
java
Thomas
Thomas

Reputation: 723

How to tell java.lang.String.split to skip the delimiter?

as input my program gets a String containing IP Addresses are separated by a line delimiter, i.e. one IP Address per line. To validate each of the addresses I do:

String[] temp;
temp = address.split(System.getProperty("line.separator"));

and then I loop though the array of Strings.

I was wondering why all but the last IP Address were always invalid. I've found out, that they look like 10.1.1.1^M

Is there a way to tell the java.lang.String.split to drop the delimiter before putting the token into the array? Or what other options do I have here? Sorry, I'm not a Java Ninja, so I thought I'll ask you guys before I start googling for hours.

Thanks Thomas

Upvotes: 2

Views: 491

Answers (4)

Peter Lawrey
Peter Lawrey

Reputation: 533500

It appears you are using a different carriage return from that of the platform. (e.g. editing on MS-DOS/Windows and running on Linux)

I would use \\s+ to break on any number of white spaces. This will also trim leading or trailing spaces.

Upvotes: 1

adarshr
adarshr

Reputation: 62583

Why don't you just use address.split("\\s+") since valid IP addresses can never contain spaces in them?

Predefined character classes 

.     Any character (may or may not match line terminators) 
\d    A digit: [0-9] 
\D    A non-digit: [^0-9] 
\s    A whitespace character: [ \t\n\x0B\f\r] 
\S    A non-whitespace character: [^\s] 
\w    A word character: [a-zA-Z_0-9] 
\W    A non-word character: [^\w]

Upvotes: 5

Lo Juego
Lo Juego

Reputation: 1325

Your line.separator is not valid. It depends on the system you are using:

\n = CR (Carriage Return) // Used as a new line character in Unix
\r = LF (Line Feed) // Used as a new line character in Mac OS
\n\r = CR + LF // Used as a new line character in Windows

Upvotes: 0

Mark Byers
Mark Byers

Reputation: 838156

The problem is that the delimiter in your file is "\r\n", but the value of System.getProperty("line.separator") is "\n". This means that the "\r" is not treated as part of the delimiter.

Upvotes: 6

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