RequestParam (Spring Framework 5.2.12.RELEASE API)

```
@Target(PARAMETER)
@Retention(RUNTIME)
@Documented
public @interface RequestParam
```
Annotation which indicates that a method parameter should be bound to a web request parameter.
Supported for annotated handler methods in Spring MVC and Spring WebFlux as follows:
- In Spring MVC, "request parameters" map to query parameters, form data, and parts in multipart requests. This is because the Servlet API combines query parameters and form data into a single map called "parameters", and that includes automatic parsing of the request body.
- In Spring WebFlux, "request parameters" map to query parameters only. To work with all 3, query, form data, and multipart data, you can use data binding to a command object annotated with ModelAttribute.
If the method parameter type is Map and a request parameter name is specified, then the request parameter value is converted to a Map assuming an appropriate conversion strategy is available.
If the method parameter is Map<String, String> or MultiValueMap<String, String> and a parameter name is not specified, then the map parameter is populated with all request parameter names and values.
Since:
2.5
Author:
Arjen Poutsma, Juergen Hoeller, Sam Brannen
See Also:
RequestMapping, RequestHeader, CookieValue

Optional Element Summary

Optional Elements
Modifier and Type	Optional Element	Description
`String`	`defaultValue`	The default value to use as a fallback when the request parameter is not provided or has an empty value.
`String`	`name`	The name of the request parameter to bind to.
`boolean`	`required`	Whether the parameter is required.
`String`	`value`	Alias for `name()`.

- Element Detail
  - value
```
@AliasFor("name")
String value
```
    Alias for name().
    Default:
    ""
- - name
```
@AliasFor("value")
String name
```
    The name of the request parameter to bind to.
    Since:
    4.2
    Default:
    ""
- - required
```
boolean required
```
    Whether the parameter is required.
    Defaults to true, leading to an exception being thrown if the parameter is missing in the request. Switch this to false if you prefer a null value if the parameter is not present in the request.
    Alternatively, provide a defaultValue(), which implicitly sets this flag to false.
    Default:
    true
- - defaultValue
```
String defaultValue
```
    The default value to use as a fallback when the request parameter is not provided or has an empty value.
    Supplying a default value implicitly sets required() to false.
    Default:
    "\n\t\t\n\t\t\n\ue000\ue001\ue002\n\t\t\t\t\n"