Spring MVC GET request with Java 8 Instant request parameter

Question

I'm trying to write a Spring MVC GET controller that takes a Java 8 Instant as request parameter:

    @GetMapping
    @JsonView(OrderListing.class)
    @Validated
    public WebSeekPaginatedResultsDto<OrderListingDto> findAll(@Valid OrderSearchCommand orderSearchCommand) {
       // Some code
    }

with:

    public class OrderSearchCommand {
        private Instant dateCreatedStart;
        private Instant dateCreatedEnd;
        // Some other fields
    }

I'm triggering a GET request from some React/Javascript code with something like that:

    http://localhost:8080/mms/front/orders?dateCreatedStart=2017-05-31T22%3A00%3A00.000Z 

Spring does not seem to like it and throws an error. Here is the error message:

    Failed to convert property value of type 'java.lang.String' to required type 'java.time.Instant' for property 'dateCreatedStart'; 
    nested exception is java.lang.IllegalStateException: 
    Cannot convert value of type 'java.lang.String' to required type 'java.time.Instant' for property 'dateCreatedStart': no matching editors or conversion strategy found

Any idea why I'm getting this?

Thank you

Answer 1

Error message is self-explanatory: there is no registered String to Instant converter.

When Controller receives request, all parameters are Strings. Spring/Jackson has list of predefined converter for most of basic types: - String > Integer - String > Boolean

But there is no default String > Instant converter.

You need to create and register one. Or you can change input type to something that Spring can handle with @DateTimeFormat annotation: How to accept Date params in a GET request to Spring MVC Controller?