optional boolean @RequestParam fails on missing parameter [SPR-4237]

[spring-projects-issues]

Kenny MacLeod opened SPR-4237 and commented

If I have a boolean @RequestParam(required=false)-annotated parameter on a @RequestMapping-annotated method, and a request comes in where that parameter is not specified, then I get an exception:

java.lang.IllegalArgumentException: Cannot convert value of type [null] to required type [boolean]: no matching editors or conversion strategy found
at org.springframework.beans.TypeConverterDelegate.convertIfNecessary(TypeConverterDelegate.java:237)
at org.springframework.beans.TypeConverterDelegate.convertIfNecessary(TypeConverterDelegate.java:107)
at org.springframework.beans.SimpleTypeConverter.convertIfNecessary(SimpleTypeConverter.java:47)
at org.springframework.beans.SimpleTypeConverter.convertIfNecessary(SimpleTypeConverter.java:41)
at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter$ArgumentsResolver.resolveArguments(AnnotationMethodHandlerAdapter.java:549)
at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:242)

Shouldn't this convert the missing parameter to false?

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Affects: 2.5 final

Issue Links:

• Default value for @RequestParam [SPR-5237] #9911 Default value for @RequestParam

[spring-projects-issues]

Juergen Hoeller commented

The intent is to declare such parameters as Boolean, allowing for null values - analogous to how we handle this in ServletRequestUtils. However, we should be throwing a nice exception in such a case: Primitive parameter types cannot be marked as required=false, essentially.

Juergen

[spring-projects-issues]

Kenny MacLeod commented

Alternatively, perhaps @RequestParam could take an optional "defaultValue" attribute? It'd have to be a string, subject to the same conversion rules as if the parameter had been present. This would work for primitives as well as reference types.

[spring-projects-issues]

Connor Barry commented

I agree, a defaultValue attribute would be really helpful here, to mimic the set of functions in ServletRequestUtils that allow a default to be set if it's not present, for example:

ServletRequestUtils.getBooleanParameter(request, name, defaultVal)