value for the annotation attribute must be constant expression

Question

I have a properties file that I read by spring annotation like this

    @Value("${platform}")
    private String platform;

after I get the platform parameter, I would like to read a second parameter depending on platform parameter value.

    @Value("${url." + platform + ."ws}")
    private String url;

but this gives error, "value for the annotation attribute must be constant expression". since there are lots of parameter changes depending on "platform" value, I am looking for a generic solution.

score 3 · Answer 1 · answered Jan 14 '16 at 14:58

You can't access platform directly in the @Value expression, but you can use Spring Expression Language to accomplish your end goal.

@Value("${platform}")
private String platform;

@Value("#{'Url.'.concat(${platform}).concat('.ws')}")
private String url;

ssedano · Answer 2 · 2011-10-31T09:01:30.403

2

The parameter is evaluated in compilation time. So it needs to be final or static final among others (ie Enum).

I don't know if the @Value annotation allows that. But you can always implement your own annotation. Extending is not possible in Java annotations.

edited Oct 31 '11 at 09:01

answered Oct 28 '11 at 08:02

ssedano

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so is there a way to use first parameter value to get second parameter? – ysnky Oct 28 '11 at 08:28
is there any sample how i can extend @Value annotaion? i am newbie in spring annotaions. – ysnky Oct 31 '11 at 08:51
No it is not possible, but you can use your own annotation. – ssedano Oct 31 '11 at 09:01

value for the annotation attribute must be constant expression

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