How to ensure mandatory parameters are passed into a Spring MVC controller method?

Question

Given a Spring-MVC controller method:

@RequestMapping(value = "/method")
public void method(@RequestParam int param1,
                   @RequestParam int param2) { /*...*/ }

If parameters are missing in the request URL, an error is reported, e.g:

JBWEB000068: message Required int parameter 'param1' is not present

I need to move the parameters into a single model class yet keep exactly the same GET request URL. So have modified method's parameter to MyModel model, which contains param1 and param2.

This works if @RequestParam is omitted but the snag is no error is reported if parameters are missing. If, on the other hand @RequestParam is included, a parameter named "model" is expected in the GET request. Is there a way to make model parameters mandatory yet keep the same request URL?

Answer 1

Use JSR-303 annotations to validate the object (and don't use primitives but the Object representations in that case).

public class MyObject {
    @NotNull
    private Integer param1;

    @NotNull
    private Integer param2;

    // Getters / Setters

}

Controller method.

@RequestMapping(value = "/method")
public void method(@Valid MyObject obj) { /*...*/ }

If you don't have a JSR-303 provider (hibernate-validator for instance) on your classpath create a Validator and use this to validate your object.

Links.

1. Spring MVC reference guide
2. Spring Validation reference guide