Prevent java.lang.IllegalArgumentException: Host name may not be null

Question

When executing an HttpUriRequest using the AndroidHttpClient, it will throw an java.lang.IllegalArgumentException: Host name may not be null when the url is faulty.

In my application, the user can input his own url. When for example http://195.168.0.q is entered, the IllegalArgument is thrown, and the app crashes.

How can I prevent this (preferably, without catching exceptions)?

@MarcoAcierno Does there even exist a regex which covers all possible correct url's? — nhaarman, May 04 '14 at 19:18
There is already a class that handles parsing of URLs and throws a very specific exception if it is not formed correctly (```MalformedURLException```). I don't think re-inventing that is a good idea. I don't think this is against coding standards, I think it is exactly why this exception class was created. — myanimal, May 04 '14 at 20:05

score 0 · Answer 1 · answered May 04 '14 at 19:13

0

Catch the exception with a 'try-catch(-finally)' block.

try {
   // your code
} catch(IllegalArgumentException) {
   // Faulty url
}

answered May 04 '14 at 19:13

Dávid Szabó

2,235
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There must be a better way, as this goes against coding standards. – nhaarman May 04 '14 at 19:14

score 0 · Answer 2 · answered May 04 '14 at 19:14

0

You should make sure the user has supplied a valid URL before trying to use it as one:

URL url;
try {
    url = new URL("http://195.168.0.q");
} catch (MalformedURLException e) {
    // tell user the URL they entered is invalid
}

answered May 04 '14 at 19:14

myanimal

3,580
26
26

Unfortunately, exactly this code does not trigger the `catch` clause. – nhaarman May 04 '14 at 20:20

Prevent java.lang.IllegalArgumentException: Host name may not be null

2 Answers2