struts2 分析

struts2 的demo 中的employee层可以清晰的暂时struts希望给开发者带来的架构

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EmployeeAction <-- AbstractCRUDAction (web 层)
^
|
EmployeeDao <-- AbstractDao <-- Dao (Domain 层，demo中也作为service存在于spring容器中)
^
|
Employee <--IDEntity

--------------------------

struts.xml 配置

<package name="skill" extends="default" namespace="/skill">
<default-interceptor-ref name="crudStack"/>

<action name="list" class="org.apache.struts2.showcase.action.SkillAction" method="list">
<result>/empmanager/listSkills.jsp</result>
<interceptor-ref name="basicStack"/>
</action>
<action name="edit" class="org.apache.struts2.showcase.action.SkillAction">
<result>/empmanager/editSkill.jsp</result>
<interceptor-ref name="params" />
<interceptor-ref name="basicStack"/>
</action>
<action name="save" class="org.apache.struts2.showcase.action.SkillAction" method="save">
<result name="input">/empmanager/editSkill.jsp</result>
<result type="redirect">edit.action?skillName=${currentSkill.name}</result>
</action>
<action name="delete" class="org.apache.struts2.showcase.action.SkillAction" method="delete">
<result name="error">/empmanager/editSkill.jsp</result>
<result type="redirect">edit.action?skillName=${currentSkill.name}</result> 这里展现了struts2具有良好的url特性，比起ww的crud!edit让人舒服多了
</action>
</package>

<package name="employee" extends="default" namespace="/employee">
<default-interceptor-ref name="crudStack"/>

<action name="list" class="org.apache.struts2.showcase.action.EmployeeAction" method="list">
<result>/empmanager/listEmployees.jsp</result>
<interceptor-ref name="basicStack"/>
</action>
<action name="edit-*" class="org.apache.struts2.showcase.action.EmployeeAction">
<param name="empId">{1}</param>
<result>/empmanager/editEmployee.jsp</result>
<interceptor-ref name="crudStack"><param name="validation.excludeMethods">execute</param></interceptor-ref>
</action>
<action name="save" class="org.apache.struts2.showcase.action.EmployeeAction" method="save">
<result name="input">/empmanager/editEmployee.jsp</result>
<result type="redirect">edit-${currentEmployee.empId}.action</result>
</action>
<action name="delete" class="org.apache.struts2.showcase.action.EmployeeAction" method="delete">
<result name="error">/empmanager/editEmployee.jsp</result>
<result type="redirect">edit-${currentEmployee.empId}.action</result>
</action>
</package>

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每一个action有自己的properties文件，非常便于管理和代码生成，
当然也有一个全局的globalMessages.properties来存放一些save,delete这些都一样的字符
employee=Employee
employee.firstName=First Name
employee.lastName=Last Name
employee.description=Description

employee.id.required=Id is required
employee.lastName.required=Last Name is required
employee.birthDate.required=Birthdate is required
employee.backtolist=Back to Employee List

每个action自己的validation
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE validators PUBLIC "-//OpenSymphony Group//XWork Validator 1.0//EN" "http://www.opensymphony.com/xwork/xwork-validator-1.0.dtd">
<validators>
<!-- Field-Validator Syntax -->
<field name="currentEmployee.empId">
<field-validator type="required">
<message key="employee.id.required"/>
</field-validator>
</field>
<field name="currentEmployee.lastName">
<field-validator type="requiredstring">
<param name="trim">true</param>
<message key="employee.lastName.required"/>
</field-validator>
</field>
<field name="currentEmployee.birthDate">
<field-validator type="required">
<message key="employee.birthDate.required"/>
</field-validator>
</field>
</validators>

--------------------------------
DAO是spring的bean,spring默认作为struts2的业务组件容器
在struts.properties中struts.objectFactory = spring

由于这里是autowire，Autowiring means to look for objects defined in Spring with the same name as your object property
所以action中所有用到IoC的地方，都会自动注入（因为action本质也是bean，下面会讲到）

<beans default-autowire="byName"> wire有四种方法：name， type， auto， constructor

<bean id="skillDao" class="org.apache.struts2.showcase.dao.SkillDao"/>
<bean id="employeeDao" class="org.apache.struts2.showcase.dao.EmployeeDao"/>

----------------------------------
struts2中的每一个action,也就是struts.xml里面声明的action,最终都将作为spring中的一个bean完成请求。
如果你不做额外的设定，struts2会自动生成这个bean。
如果你有特殊的需要，还可以在applicationContext.xml自己声明这个bean
你必须根据需要来决定是否再次声明
struts.xml
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
<include file="struts-default.xml"/>

<package name="default" extends="struts-default">
<action name="foo" class="com.acme.Foo"> 这个foo，在applicationConext.xml中没有声明，struts会自动生成一个bean
<result>foo.ftl</result>
</action>
</package>

<package name="secure" namespace="/secure" extends="default">
<action name="bar" class="bar"> 这个foo，在applicationConext.xml中声明了，struts会使用下面配置
<result>bar.ftl</result>
</action>
</package>
</struts>

applicationConext.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans default-autowire="autodetect">
<bean id="bar" class="com.my.BarClass" singleton="false"/>
...
</beans>

-------------------------
无缝集成ajax
只要声明了theme="ajax"，该标签控件的操作就被转换成ajax，请求发送到AjaxRemoteForm
Configured Editor configuration:
<s:form id="form2" action="AjaxRemoteForm" method="post">
<s:textarea id="editor2" name="data" theme="ajax" cols="50" rows="10" value="Test Data 2">
<s:param name="editorControls">textGroup;|;justifyGroup;|;listGroup;|;indentGroup</s:param>
</s:textarea>
<s:submit value="Submit"/>
</s:form>

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集成了多种模板
jsp,velocity,freemaker

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struts2 继承了ww2的优良传统，并且摈弃了ww2的一些缺陷，也可以看成是对ww2的一次重购。
无疑是目前最主流，最强大的MVC框架了。

它实现了和spring的完美结合

集成了ajax（dojo+dwr）

其插件支持jasperreports，jfreechart