Struts 2.5.2 HTTP Status 404 - There is no Action mapped for namespace [/] and action name [regist_A

使用Struts2.5.2   学习Action通配符时，出现错误：HTTP Status 404 - There is no Action mapped for namespace [/] and action name [regist_Action] associated with context path [/wildcard1].

在确保代码无误的情况下，用Struts2.3 JAR包代替后可正常使用，而Struts2.5不行，最后确定是Struts2.5.2 JAR本身的问题。

查看文档struts-2.5.2\docs\docs\action-configuration.html后找到问题所在。

首先，2.3版本中多了一个Strict DMI，当设置包属性

strict-method-invocation="true"

 时，Struts会拒绝一切不明确的方法属性包括通配符。（有点难翻译，具体看原文）

而2.5版本中的 Method Invocation(SMI)继承了2.3中的Strict DMI，属性strict-method-invocation被默认设置为true，所以才会出现这个错误。

解决方法：修改struts.xml，在<allowed-methods>准确添加method

<struts>
<package name="lee" extends="struts-default">
<action name="*_Action" class="org.crazyit.app.action.LoginRegistAction"
method="{1}">
<!-- 定义逻辑视图和物理视图之间的映射关系 -->
<result name="error">/WEB-INF/content/error.jsp</result>
<result>/WEB-INF/content/welcome.jsp</result>
<allowed-methods>login,regist</allowed-methods>
</action>
<action name="*">
<result>/WEB-INF/content/{1}.jsp</result>
</action>
</package>

</struts>

附docs部分原文：

Strict DMI

In Struts 2.3, an option was added to restrict the methods that DMI can invoke. First, set the attribute 

strict-method-invocation="true"

 on your 

<package>

 element. This tells Struts to reject any method that is not explicitly allowed
via either the 

method

 attribute (including wildcards) or the 

<allowed-methods>

 tag. Then specify 

<allowed-methods>

 as a comma-separated list of method names in your 

<action>

. (If you specify a 

method

 attribute
for your action, you do not need to list it in 

<allowed-methods>

.)

Note that you can specify 

<allowed-methods>

 even without 

strict-method-invocation

. This restricts access only for the specific actions that have 

<allowed-methods>

.

Example struts.xml

Strict Method Invocation

In Struts 2.5 the Strict DMI was extended and it's called Strict Method Invocation aka SMI. You can imagine that the DMI is a "border police", where SMI is a "tax police" and keeps eye on internals. With this version, SMI is enabled by default
(

strict-method-invocation

 attribute is set to 

true

 by default in 

struts-default

 package), you have option to disable it per package - there is no global switch to disable SMI for the whole application. To gain advantage
of new configuration option please use the latest DTD definition:

Struts 2.5 DTD

SMI works in the following way:

<allowed-methods>

 / 

@AllowedMethods

 is defined per action - SMI works without switching it on but just for those actions (plus adding 

<global-allowed-methods/>

)
SMI is enabled but no 

<allowed-methods>

 / 

@AllowedMethods

 are defined - SMI works but only with 

<global-allowed-methods/>

SMI is disabled - call to any action method is allowed that matches the default RegEx - 

([A-Za-z0-9_$]*)

You can redefine the default RegEx by using a constant as follow 

<constant name="struts.strictMethodInvocation.methodRegex" value="([a-zA-Z]*)"/>

When using wildcard mapping in actions' definitions SMI works in two ways:
SMI is disabled - any wildcard will be substituted with the default RegEx, ie.: 

<action name="Person*" method="perform*">

 will be translated into 

allowedMethod = "regex:perform([A-Za-z0-9_$]*)".

SMI is enabled - no wildcard substitution will happen, you must strictly define which methods can be accessed by annotations or 

<allowed-method/>

 tag.

You can configure SMI per 

<action/>

 using 

<allowed-methods/>

 tag or via 

@AllowedMethod

 annotation plus using per 

<package/>

 

<global-allowed-methods/>

, see the
examples below:

SMI via struts.xml

SMI via annotation on action class level

SMI via annotation on package level (in package-info.java)

Allowed methods can be defined as:

literals ie. in xml: 

execute,cancel 

or in annotation:

 {"
execute
", "[code]cancel

"}
[/code]

patterns when using with wildcard mapping, i.e 

<action ... method="do{2}"/>

RegExs using 

regex:

 prefix, ie: 

<global-allowed-methods>execute,input,cancel,regex:user([A-Z]*)</global-allowed-methods>

Please be aware when using your own 

Configurationprovider

 that the logic to set allowed methods is defined in built-in providers - 

XmlConfigurationProvider

 and 

PackageBasedActionConfigBuilder

 - and you must replicate such
logic in your code as by default only 

execute

 method is allowed, even when SMI is disabled.