`@RequestParam`

You can use the @RequestParam annotation to bind Servlet request parameters (that is, query parameters or form data) to a method argument in a controller.

The following example shows how to do so:

Java

@Controller
@RequestMapping("/pets")
public class EditPetForm {

  // ...

  @GetMapping
  public String setupForm(@RequestParam("petId") int petId, Model model) { (1)
    Pet pet = this.clinic.loadPet(petId);
    model.addAttribute("pet", pet);
    return "petForm";
  }

  // ...

}

1	Using `@RequestParam` to bind `petId`.

By default, method parameters that use this annotation are required, but you can specify that a method parameter is optional by setting the @RequestParam annotation’s required flag to false or by declaring the argument with an java.util.Optional wrapper.

Type conversion is automatically applied if the target method parameter type is not String. See Type Conversion.

Declaring the argument type as an array or list allows for resolving multiple parameter values for the same parameter name.

When an @RequestParam annotation is declared as a Map<String, String> or MultiValueMap<String, String>, without a parameter name specified in the annotation, then the map is populated with the request parameter values for each given parameter name.

Note that use of @RequestParam is optional (for example, to set its attributes). By default, any argument that is a simple value type (as determined by BeanUtils#isSimpleProperty) and is not resolved by any other argument resolver, is treated as if it were annotated with @RequestParam.