SSH学习之Struts1深入学习

最新推荐文章于 2021-02-22 06:33:46 发布

黄国攀

最新推荐文章于 2021-02-22 06:33:46 发布

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分类专栏： SSH 文章标签： java maven ssh

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本文介绍了Struts框架中的高级特性，包括动态ActionForm的配置与使用、DispathAction及MappingDispathAction的设计与实现，旨在简化表单处理并提供灵活的操作方式。

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1.动态ActionForm。

前文已经实现基于静态的ActionForm，而如果每一个表单都需要创建一个ActionForm,那么ActionForm就太多了。那么Struts可以通过动态的DynaActionForm来解决上述问题，只需要配置，而不用再创建新的ActionForm。

①配置：

<form-beans>
		<!-- 定义DynaActionForm，至少指定两个属性: name(自定义） , type 指定Struts中的路径 -->	
		<form-bean name="dynaForm" type="org.apache.struts.action.DynaActionForm">
			<form-property name="userName" type="java.lang.String"/>
			<form-property name="pswd" type="java.lang.String"/>
		</form-bean>
	</form-beans>

②Action中取值，是通过强制转换form为DynaActionForm，且要得到的对象的值，类似map的key/value，getString(name)，name就是属性名字。

public class DynaAction extends Action {

	public ActionForward execute(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {
		DynaActionForm form2 = (DynaActionForm) form;
		String userName = form2.getString("userName");
		String pswd = form2.getString("pswd");
		if ("admin".equals(userName) && "admin".equals(pswd)) {
			System.out.println(userName+"    " + pswd);
			return mapping.findForward("error");
		}

		return mapping.findForward("error");

	}
}

2.DispathAction

如果要对用户实现增删改查有2种方式：

①创建4个Action来实现功能，就显得很杂，难以管理。

②使用DispathAction,不用重写execute方法，而是定义自己需要实现的Action方法。

③配置：DispathAction在xml的配置中比Action多了一个parameter属性，该属性自定义了要去访问DispathAction方法的字段。

<action-mappings>
		<action path="/login" type="com.example.UserAction" name="dynaForm_2"
			scope="request" parameter="method">
			<!-- 配置局部Forward -->
			<forward name="welcome" path="/index.jsp" />
			<forward name="input" path="/login.jsp" />
			<forward name="main" path="/main.jsp"></forward>
			<forward name="add" path="/add_success.jsp"></forward>
			<forward name="delete" path="/delete_success.jsp"></forward>
			<forward name="modify" path="/modify_success.jsp"></forward>
		</action>

	</action-mappings>

④实现：

public class UserAction extends DispatchAction{

	
	public ActionForward add(ActionMapping arg0, ActionForm arg1,
			HttpServletRequest arg2, HttpServletResponse arg3) throws Exception {
		// TODO Auto-generated method stub
		PrintWriter out=arg3.getWriter();  
        out.println("add!!!!!");  
        return arg0.findForward("add");
	}

	public ActionForward delete(ActionMapping arg0, ActionForm arg1,
			HttpServletRequest arg2, HttpServletResponse arg3) throws Exception {
		// TODO Auto-generated method stub
		PrintWriter out=arg3.getWriter();  
        out.println("add!!!!!");  
        return arg0.findForward("delete");
	}

	public ActionForward modify(ActionMapping arg0, ActionForm arg1,
			HttpServletRequest arg2, HttpServletResponse arg3) throws Exception {
		// TODO Auto-generated method stub
		PrintWriter out=arg3.getWriter();  
        out.println("add!!!!!");  
        return arg0.findForward("modify");
	}

}

⑤访问方式：

        <a href="login.do?method=add">add</a><br>
	<a href="login.do?method=delete">delete</a><br>
	<a href="login.do?method=modify">modify</a><br>

3.MappingDispathAction

使用DispathAction每次都是同一个parameter字段，容易出错，所以可以使用MappingDispathAction。

①配置：其中parameter中的名字要与Action中的名字一模一样。

<action path="/add" type="com.example.UserMapAction" name="dynaForm_2"
		    scope="request" parameter="add"></action>
		<action path="/delete" type="com.example.UserMapAction" name="dynaForm_2"
		    scope="request" parameter="delete"></action>
		<action path="/modify" type="com.example.UserMapAction" name="dynaForm_2"
		    scope="request" parameter="modify"></action>

②实现：

public class UserMapAction extends MappingDispatchAction{

	
	public ActionForward add(ActionMapping arg0, ActionForm arg1,
			HttpServletRequest arg2, HttpServletResponse arg3) throws Exception {
		// TODO Auto-generated method stub
		PrintWriter out=arg3.getWriter();  
        out.println("add!!!!!");  
        return arg0.findForward("add");
	}

	public ActionForward delete(ActionMapping arg0, ActionForm arg1,
			HttpServletRequest arg2, HttpServletResponse arg3) throws Exception {
		// TODO Auto-generated method stub
		PrintWriter out=arg3.getWriter();  
        out.println("add!!!!!");  
        return arg0.findForward("delete");
	}

	public ActionForward modify(ActionMapping arg0, ActionForm arg1,
			HttpServletRequest arg2, HttpServletResponse arg3) throws Exception {
		// TODO Auto-generated method stub
		PrintWriter out=arg3.getWriter();  
        out.println("add!!!!!");  
        return arg0.findForward("modify");
	}

}

③访问方式：

	<a href="add.do">add_mapping</a><br>
	<a href="delete.do">delete_mapping</a><br>
	<a href="modify.do">modify_mapping</a><br>