Struts2 学习笔记6--访问web元素-模块包含
访问web元素
struts.xml:
<package name="login" extends="struts-default" namespace="/login">
??????? <action name="login*" action="" method="post">
用户名：<input type="text" name="name"/>
密码：<input type="text" name="password"/>
<br />
<input type="button" value="submit1" onclick="javascript:document.f.action='login/login1';document.f.submit();" />
<input type="button" value="submit2" onclick="javascript:document.f.action='login/login2';document.f.submit();" />
<input type="button" value="submit3" onclick="javascript:document.f.action='login/login3';document.f.submit();" />
<input type="button" value="submit4" onclick="javascript:document.f.action='login/login4';document.f.submit();" />
</form>
result jsp:
??? User Login Success!
??? <br />
??? <s:property value="#request.r1"/> | <%=request.getAttribute("r1") %> <br />
??? <s:property value="#session.s1"/> | <%=session.getAttribute("s1") %> <br />
??? <s:property value="#application.a1"/> | <%=application.getAttribute("a1") %> <br />
??? <s:property value="#attr.a1"/><br />
??? <s:property value="#attr.s1"/><br />
??? <s:property value="#attr.r1"/><br />
??? <s:debug></s:debug>
??? <br />
注意：#attr表示模糊查找属性值，在request>session>application三个范围中查找属性。
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访问request等三种方式：
1、从上下文中取得，直接赋值
??? public LoginAction1() {
??? ??? request = (Map)ActionContext.getContext().get("request");
??? ??? session = ActionContext.getContext().getSession();
??? ??? application = ActionContext.getContext().getApplication();
??? }
2、 实现RequestAware,SessionAware, ApplicationAware三个接口，依赖注入（控制反转）?? 最常用
public class LoginAction2 extends ActionSupport implements RequestAware,SessionAware, ApplicationAware {
??? private Map<String, Object> request;
??? private Map<String, Object> session;
??? private Map<String, Object> application;
???
??? //DI dependency injection
??? //IoC inverse of control
??? public String execute() {
??? ??? request.put("r1", "r1");
??? ??? session.put("s1", "s1");
??? ??? application.put("a1", "a1");
??? ??? return SUCCESS;
??? }
??? @Override
??? public void setRequest(Map<String, Object> request) {
??? ??? this.request = request;
??? }
??? @Override
??? public void setSession(Map<String, Object> session) {
??? ??? this.session = session;
??? }
??? @Override
??? public void setApplication(Map<String, Object> application) {
??? ??? this.application = application;
??? }
}
3、直接从ServletActionContext中获取
??? public LoginAction3() {
??? ??? request = ServletActionContext.getRequest();
??? ??? session = request.getSession();
??? ??? application = session.getServletContext();
??? }
4、实现ServletRequestAware接口,实现setServletRequest方法
public class LoginAction4 extends ActionSupport implements ServletRequestAware {
??? private HttpServletRequest request;
??? private HttpSession session;
??? private ServletContext application;
???
??? public String execute() {
??? ??? request.setAttribute("r1", "r1");
??? ??? session.setAttribute("s1", "s1");
??? ??? application.setAttribute("a1", "a1");
??? ??? return SUCCESS;
??? }
??? @Override
??? public void setServletRequest(HttpServletRequest request) {
??? ??? this.request = request;
??? ??? this.session = request.getSession();
??? ??? this.application = session.getServletContext();
??? }
???
}
结论：
取得Map类型request,session,application,真实类型 HttpServletRequest, HttpSession, ServletContext的引用:
1.前三者：依赖于容器
2.前三者：IOC (只用这种)
3.后三者：依赖于容器
4.后三者：IOC
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模块包含
在struts.xml中配置可包含其他xml中的配置,这样利于模块配置之间解耦
struts.xml:
<struts>
??? <constant name="struts.devMode" value="true" />
??? <include file="login.xml" />
</struts>
login.xml
<struts>
??? <package name="login" extends="struts-default" namespace="/login">
??????? <action name="login*" namespace="/" extends="struts-default">
??? ??? <default-action-ref name="index"></default-action-ref>
??? ??? <action name="index">
??? ??? ??? <result>/default.jsp</result>
??? ??? </action>
</package>
在struts2文档中这样说明：
Action Default
Usually, if an action is requested, and the framework can't map the request to an action name, the result will be the usual "404 - Page not found" error. But, if you would prefer that an omnibus action handle any unmatched requests, you can specify a default action. If no other action matches, the default action is used instead.
<package name="Hello" extends="action-default">
??? <default-action-ref name="UnderConstruction"/>
??? <action name="UnderConstruction">
??????? <result>/UnderConstruction.jsp</result>
??? </action>
??? ...
There are no special requirements for the default action. Each package can have its own default action, but there should only be one default action per namespace.
???? One to a Namespace
The default action features should be set up so that there is only one default action per namespace. If you have multiple packages declaring a default action with the same namespace, there is no guarantee which action will be the default.
说明：每个namespace中只能配置一个default-action-ref。
Action总结：
1.??? 实现一个Action的最常用方式：从ActionSupport继承
2.??? DMI动态方法调用 ！
3.??? 通配符配置 * {1} {2} …
a)??? *_*
4.??? 接收参数的方法（一般用属性或者DomainModel来接收）
5.??? 简单参数验证addFieldError
a)??? 一般不使用Struts2的UI标签
6.??? 访问Web元素
a)??? Map类型
i.??? IoC
ii.??? 依赖Struts2
b)??? 原始类型
i.??? IoC
ii.??? 依赖Struts2
7.??? 包含文件配置
8.??? 默认action处理
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