java.lang.Object
- org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver
- - org.springframework.web.method.annotation.RequestParamMethodArgumentResolver

All Implemented Interfaces:
HandlerMethodArgumentResolver, UriComponentsContributor
```
public class RequestParamMethodArgumentResolver
extends AbstractNamedValueMethodArgumentResolver
implements UriComponentsContributor
```
Resolves method arguments annotated with @RequestParam, arguments of type MultipartFile in conjunction with Spring's MultipartResolver abstraction, and arguments of type javax.servlet.http.Part in conjunction with Servlet 3.0 multipart requests. This resolver can also be created in default resolution mode in which simple types (int, long, etc.) not annotated with @RequestParam are also treated as request parameters with the parameter name derived from the argument name.
If the method parameter type is Map, the name specified in the annotation is used to resolve the request parameter String value. The value is then converted to a Map via type conversion assuming a suitable Converter or PropertyEditor has been registered. Or if a request parameter name is not specified the RequestParamMapMethodArgumentResolver is used instead to provide access to all request parameters in the form of a map.
A WebDataBinder is invoked to apply type conversion to resolved request header values that don't yet match the method parameter type.
Since:
3.1
Author:
Arjen Poutsma, Rossen Stoyanchev, Brian Clozel
See Also:
RequestParamMapMethodArgumentResolver

Nested Class Summary
- Nested classes/interfaces inherited from class org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver
  AbstractNamedValueMethodArgumentResolver.NamedValueInfo

Constructor Summary

Constructors
Constructor	Description
`RequestParamMethodArgumentResolver(boolean useDefaultResolution)`	Create a new `RequestParamMethodArgumentResolver` instance.
`RequestParamMethodArgumentResolver(ConfigurableBeanFactory beanFactory, boolean useDefaultResolution)`	Create a new `RequestParamMethodArgumentResolver` instance.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`contributeMethodArgument(MethodParameter parameter, Object value, UriComponentsBuilder builder, Map<String,Object> uriVariables, ConversionService conversionService)`	Process the given method argument and either update the `UriComponentsBuilder` or add to the map with URI variables to use to expand the URI after all arguments are processed.
`protected AbstractNamedValueMethodArgumentResolver.NamedValueInfo`	`createNamedValueInfo(MethodParameter parameter)`	Create the `AbstractNamedValueMethodArgumentResolver.NamedValueInfo` object for the given method parameter.
`protected String`	`formatUriValue(ConversionService cs, TypeDescriptor sourceType, Object value)`
`protected void`	`handleMissingValue(String name, MethodParameter parameter, NativeWebRequest request)`	Invoked when a named value is required, but `AbstractNamedValueMethodArgumentResolver.resolveName(String, MethodParameter, NativeWebRequest)` returned `null` and there is no default value.
`protected Object`	`resolveName(String name, MethodParameter parameter, NativeWebRequest request)`	Resolve the given parameter type and value name into an argument value.
`boolean`	`supportsParameter(MethodParameter parameter)`	Supports the following: @RequestParam-annotated method arguments.

Methods inherited from class org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver
handleMissingValue, handleResolvedValue, resolveArgument

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - RequestParamMethodArgumentResolver
```
public RequestParamMethodArgumentResolver(boolean useDefaultResolution)
```
    Create a new RequestParamMethodArgumentResolver instance.
    Parameters:
    useDefaultResolution - in default resolution mode a method argument that is a simple type, as defined in BeanUtils.isSimpleProperty(java.lang.Class<?>), is treated as a request parameter even if it isn't annotated, the request parameter name is derived from the method parameter name.
  - RequestParamMethodArgumentResolver
```
public RequestParamMethodArgumentResolver(@Nullable
                                          ConfigurableBeanFactory beanFactory,
                                          boolean useDefaultResolution)
```
    Create a new RequestParamMethodArgumentResolver instance.
    Parameters:
    beanFactory - a bean factory used for resolving ${...} placeholder and #{...} SpEL expressions in default values, or null if default values are not expected to contain expressions
    useDefaultResolution - in default resolution mode a method argument that is a simple type, as defined in BeanUtils.isSimpleProperty(java.lang.Class<?>), is treated as a request parameter even if it isn't annotated, the request parameter name is derived from the method parameter name.
- Method Detail
  - supportsParameter
```
public boolean supportsParameter(MethodParameter parameter)
```
    Supports the following:
    @RequestParam-annotated method arguments. This excludes Map params where the annotation does not specify a name. See RequestParamMapMethodArgumentResolver instead for such params.
    Arguments of type MultipartFile unless annotated with @RequestPart.
    Arguments of type Part unless annotated with @RequestPart.
    In default resolution mode, simple type arguments even if not with @RequestParam.
    Specified by:
    supportsParameter in interface HandlerMethodArgumentResolver
    Specified by:
    supportsParameter in interface UriComponentsContributor
    Parameters:
    parameter - the method parameter to check
    Returns:
    true if this resolver supports the supplied parameter; false otherwise
  - createNamedValueInfo
```
protected AbstractNamedValueMethodArgumentResolver.NamedValueInfo createNamedValueInfo(MethodParameter parameter)
```
    Description copied from class: AbstractNamedValueMethodArgumentResolver
    Create the AbstractNamedValueMethodArgumentResolver.NamedValueInfo object for the given method parameter. Implementations typically retrieve the method annotation by means of MethodParameter.getParameterAnnotation(Class).
    Specified by:
    createNamedValueInfo in class AbstractNamedValueMethodArgumentResolver
    Parameters:
    parameter - the method parameter
    Returns:
    the named value information
  - resolveName
```
@Nullable
protected Object resolveName(String name,
                             MethodParameter parameter,
                             NativeWebRequest request)
                      throws Exception
```
    Description copied from class: AbstractNamedValueMethodArgumentResolver
    Resolve the given parameter type and value name into an argument value.
    Specified by:
    resolveName in class AbstractNamedValueMethodArgumentResolver
    Parameters:
    name - the name of the value being resolved
    parameter - the method parameter to resolve to an argument value (pre-nested in case of a Optional declaration)
    request - the current request
    Returns:
    the resolved argument (may be null)
    Throws:
    Exception - in case of errors
  - handleMissingValue
```
protected void handleMissingValue(String name,
                                  MethodParameter parameter,
                                  NativeWebRequest request)
                           throws Exception
```
    Description copied from class: AbstractNamedValueMethodArgumentResolver
    Invoked when a named value is required, but AbstractNamedValueMethodArgumentResolver.resolveName(String, MethodParameter, NativeWebRequest) returned null and there is no default value. Subclasses typically throw an exception in this case.
    Overrides:
    handleMissingValue in class AbstractNamedValueMethodArgumentResolver
    Parameters:
    name - the name for the value
    parameter - the method parameter
    request - the current request
    Throws:
    Exception
  - contributeMethodArgument
```
public void contributeMethodArgument(MethodParameter parameter,
                                     @Nullable
                                     Object value,
                                     UriComponentsBuilder builder,
                                     Map<String,Object> uriVariables,
                                     ConversionService conversionService)
```
    Description copied from interface: UriComponentsContributor
    Process the given method argument and either update the UriComponentsBuilder or add to the map with URI variables to use to expand the URI after all arguments are processed.
    Specified by:
    contributeMethodArgument in interface UriComponentsContributor
    Parameters:
    parameter - the controller method parameter (never null)
    value - the argument value (possibly null)
    builder - the builder to update (never null)
    uriVariables - a map to add URI variables to (never null)
    conversionService - a ConversionService to format values as Strings
  - formatUriValue
```
@Nullable
protected String formatUriValue(@Nullable
                                ConversionService cs,
                                @Nullable
                                TypeDescriptor sourceType,
                                @Nullable
                                Object value)
```

Class RequestParamMethodArgumentResolver

Nested Class Summary

Nested classes/interfaces inherited from class org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver

Constructor Summary

Method Summary

Methods inherited from class org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver

Methods inherited from class java.lang.Object

Constructor Detail

RequestParamMethodArgumentResolver

RequestParamMethodArgumentResolver

Method Detail

supportsParameter

createNamedValueInfo

resolveName

handleMissingValue

contributeMethodArgument

formatUriValue