public class ParameterMethodNameResolver extends Object implements MethodNameResolver
MethodNameResolverwhich supports several strategies for mapping parameter values to the names of methods to invoke.
The simplest strategy looks for a specific named parameter, whose value is
considered the name of the method to invoke. The name of the parameter may be
specified as a JavaBean property, if the default
action is not
The alternative strategy uses the very existence of a request parameter (
i.e. a request parameter with a certain name is found) as an indication that a
method with the same name should be dispatched to. In this case, the actual
request parameter value is ignored. The list of parameter/method names may
be set via the
methodParamNames JavaBean property.
The second resolution strategy is primarily expected to be used with web pages containing multiple submit buttons. The 'name' attribute of each button should be set to the mapped method name, while the 'value' attribute is normally displayed as the button label by the browser, and will be ignored by the resolver.
Note that the second strategy also supports the use of submit buttons of
type 'image'. That is, an image submit button named 'reset' will normally be
submitted by the browser as two request paramters called 'reset.x', and
'reset.y'. When checking for the existence of a paramter from the
methodParamNames list, to indicate that a specific method should
be called, the code will look for request parameter in the "reset" form
(exactly as spcified in the list), and in the "reset.x" form ('.x' appended to
the name in the list). In this way it can handle both normal and image submit
buttons. The actual method name resolved if there is a match will always be
the bare form without the ".x".
Note: If both strategies are configured, i.e. both "paramName" and "methodParamNames" are specified, then both will be checked for any given request. A match for an explicit request parameter in the "methodParamNames" list always wins over a value specified for a "paramName" action parameter.
For use with either strategy, the name of a default handler method to use when there is no match, can be specified as a JavaBean property.
For both resolution strategies, the method name is of course coming from some sort of view code, (such as a JSP page). While this may be acceptable, it is sometimes desireable to treat this only as a 'logical' method name, with a further mapping to a 'real' method name. As such, an optional 'logical' mapping may be specified for this purpose.
|Modifier and Type||Field and Description|
Default name for the parameter whose value identifies the method to invoke: "action".
|Constructor and Description|
|Modifier and Type||Method and Description|
Return a method name that can handle this request.
Set the name of the default handler method that should be used when no parameter was found in the request
Specifies a set of optional logical method name mappings.
Set a String array of parameter names, where the very existence of a parameter in the list (with value ignored) means that a method of the same name should be invoked.
Set the name of the parameter whose value identifies the name of the method to invoke.
public static final String DEFAULT_PARAM_NAME
protected final Log logger
public void setParamName(String paramName)
Alternatively, specify parameter names where the very existence of each parameter means that a method of the same name should be invoked, via the "methodParamNames" property.
public void setMethodParamNames(String methodParamNames)
logicalMappingsproperty, in which case it can be considered a logical name only.
public void setLogicalMappings(Properties logicalMappings)
Note that in the case of no match, where the
is used if available, that method name is considered to already be the real method
name, and is not run through the logical mapping.
logicalMappings- a Properties object mapping logical method names to real method names
public void setDefaultMethodName(String defaultMethodName)
public String getHandlerMethodName(HttpServletRequest request) throws NoSuchRequestHandlingMethodException
request- current HTTP request
null; throws exception if not resolvable.
NoSuchRequestHandlingMethodException- if no handler method can be found for the given request