org.springframework.web.method.annotation

Class RequestParamMethodArgumentResolver

java.lang.Object

org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver

org.springframework.web.method.annotation.RequestParamMethodArgumentResolver

All Implemented Interfaces:

HandlerMethodArgumentResolver

public class RequestParamMethodArgumentResolver
extends AbstractNamedValueMethodArgumentResolver

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

See Also:

RequestParamMapMethodArgumentResolver

Nested Class Summary

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

AbstractNamedValueMethodArgumentResolver.NamedValueInfo

Constructor Summary

Constructors

Constructor and Description
RequestParamMethodArgumentResolver(ConfigurableBeanFactory beanFactory, boolean useDefaultResolution)

Method Summary

Methods

Modifier and Type	Method and Description
protected AbstractNamedValueMethodArgumentResolver.NamedValueInfo	createNamedValueInfo(MethodParameter parameter) Create the AbstractNamedValueMethodArgumentResolver.NamedValueInfo object for the given method parameter.
protected void	handleMissingValue(String paramName, MethodParameter parameter) 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 webRequest) Resolves 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

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(ConfigurableBeanFactory beanFactory,
                                  boolean useDefaultResolution)

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 itsn'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 doesn't specify a name. See RequestParamMapMethodArgumentResolver instead for such params.
• Arguments of type MultipartFile unless annotated with @RequestPart.
• Arguments of type javax.servlet.http.Part unless annotated with @RequestPart.
• In default resolution mode, simple type arguments even if not with @RequestParam.

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

protected Object resolveName(String name,
                 MethodParameter parameter,
                 NativeWebRequest webRequest)
                      throws Exception

Description copied from class: AbstractNamedValueMethodArgumentResolver

Resolves 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

webRequest - the current request

Returns:

the resolved argument. May be null

Throws:

Exception - in case of errors

handleMissingValue

protected void handleMissingValue(String paramName,
                      MethodParameter parameter)
                           throws ServletException

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.

Specified by:

handleMissingValue in class AbstractNamedValueMethodArgumentResolver

Parameters:

paramName - the name for the value

parameter - the method parameter

Throws:

ServletException