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.

Answer 1

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;