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Spring Framework 2.1.0 API 文档英文版
ParameterMethodNameResolver (Spring Framework API 2.1) - Spring Framework 2.1.0 API 文档英文版
org.springframework.web.servlet.mvc.multiaction
Class ParameterMethodNameResolver
java.lang.Object
org.springframework.web.servlet.mvc.multiaction.ParameterMethodNameResolver
- All Implemented Interfaces:
- MethodNameResolver
public class ParameterMethodNameResolver
- extends Object
- implements MethodNameResolver
Implementation of MethodNameResolver which 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
acceptable.
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.
- Author:
- Rod Johnson, Juergen Hoeller, Colin Sampaleanu
- See Also:
setParamName(java.lang.String),
setMethodParamNames(java.lang.String[]),
setLogicalMappings(java.util.Properties),
setDefaultMethodName(java.lang.String)
|
Method Summary |
String |
getHandlerMethodName(HttpServletRequest request)
Return a method name that can handle this request. |
void |
setDefaultMethodName(String defaultMethodName)
Set the name of the default handler method that should be
used when no parameter was found in the request |
void |
setLogicalMappings(Properties logicalMappings)
Specifies a set of optional logical method name mappings. |
void |
setMethodParamNames(String[] methodParamNames)
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. |
void |
setParamName(String paramName)
Set the name of the parameter whose value identifies the name of
the method to invoke. |
| Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
DEFAULT_PARAM_NAME
public static final String DEFAULT_PARAM_NAME
- Default name for the parameter whose value identifies the method to invoke:
"action".
- See Also:
- Constant Field Values
logger
protected final Log logger
ParameterMethodNameResolver
public ParameterMethodNameResolver()
setParamName
public void setParamName(String paramName)
- Set the name of the parameter whose value identifies the name of
the method to invoke. Default is "action".
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.
- See Also:
setMethodParamNames(java.lang.String[])
setMethodParamNames
public void setMethodParamNames(String[] methodParamNames)
- 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. This target method name may then be optionally
further mapped via the
logicalMappings property, in which case it
can be considered a logical name only.
- See Also:
setParamName(java.lang.String)
setLogicalMappings
public void setLogicalMappings(Properties logicalMappings)
- Specifies a set of optional logical method name mappings. For both resolution
strategies, the method name initially comes in from the view layer. If that needs
to be treated as a 'logical' method name, and mapped to a 'real' method name, then
a name/value pair for that purpose should be added to this Properties instance.
Any method name not found in this mapping will be considered to already be the
real method name.
Note that in the case of no match, where the defaultMethodName property
is used if available, that method name is considered to already be the real method
name, and is not run through the logical mapping.
- Parameters:
logicalMappings - a Properties object mapping logical method names to real
method names
setDefaultMethodName
public void setDefaultMethodName(String defaultMethodName)
- Set the name of the default handler method that should be
used when no parameter was found in the request
getHandlerMethodName
public String getHandlerMethodName(HttpServletRequest request)
throws NoSuchRequestHandlingMethodException
- Description copied from interface:
MethodNameResolver
- Return a method name that can handle this request. Such
mappings are typically, but not necessarily, based on URL.
- Specified by:
getHandlerMethodName in interface MethodNameResolver
- Parameters:
request - current HTTP request
- Returns:
- a method name that can handle this request.
Never returns
null; throws exception if not resolvable.
- Throws:
NoSuchRequestHandlingMethodException - if no handler method
can be found for the given request
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