spring JpetStore学习笔记(四)

介绍完配置文件过后,具体看看项目的MVC和DAO层
修改web.xml文件

<servlet-mapping>
    <!--
        <servlet-name>petstore</servlet-name>
    -->    
        <servlet-name>action</servlet-name>
        
        <url-pattern>*.do</url-pattern>
    </servlet-mapping>

 这里先使用struts的action,先不用spring的MVC,映射配置文件是struts-config.xml

首先看看用户注册页面struts目录下NewAccountForm.jsp,这里使用的是jstl标签库
<%@ include file="IncludeAccountFields.jsp" %>包含了用户详细信息
提交的action是/shop/newAccount.do
察看struts-config.xml

<action path="/shop/newAccount"
                  type="org.springframework.samples.jpetstore.web.struts.NewAccountAction"
               name="workingAccountForm" scope="session" validate="true"
                  input="/WEB-INF/jsp/struts/NewAccountForm.jsp">
            <forward name="success" path="/shop/index.do"/>
</action>

处理类是org.springframework.samples.jpetstore.web.struts.NewAccountAction
FORM是workingAccountForm
scope="session"  作用域为session 
validate="true"  使用校验,调用form中的validate()方法

NewAccountAction的源码:

package org.springframework.samples.jpetstore.web.struts;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.springframework.beans.support.PagedListHolder;
import org.springframework.samples.jpetstore.domain.Account;

public class NewAccountAction extends BaseAction ...{
  public ActionForward execute(ActionMapping mapping, ActionForm form,
                            HttpServletRequest request, HttpServletResponse response) throws Exception ...{
    AccountActionForm acctForm = (AccountActionForm) form;
        
        if (AccountActionForm.VALIDATE_NEW_ACCOUNT.equals(acctForm.getValidate())) ...{
            acctForm.getAccount().setListOption(request.getParameter("account.listOption") != null);
            acctForm.getAccount().setBannerOption(request.getParameter("account.bannerOption") != null);
            Account account = acctForm.getAccount();
            String username = acctForm.getAccount().getUsername();
            getPetStore().insertAccount(account);
            acctForm.setAccount(getPetStore().getAccount(username));
            PagedListHolder myList = new PagedListHolder(getPetStore().getProductListByCategory
                                                                                                                 (account.getFavouriteCategoryId()));
            myList.setPageSize(4);
            acctForm.setMyList(myList);
            request.getSession().setAttribute("accountForm", acctForm);
            request.getSession().removeAttribute("workingAccountForm");
            return mapping.findForward("success");
        }
        else ...{
            request.setAttribute("message", "Your account was not created because the submitted
                                                                             information was not validated.");
            return mapping.findForward("failure");
        }
  }
}

一句一句来-------------------
1>
AccountActionForm继承BaseAction
BaseAction中:

public abstract class BaseAction extends Action ...{

  private PetStoreFacade petStore;

    public void setServlet(ActionServlet actionServlet) ...{
        super.setServlet(actionServlet);
        if (actionServlet != null) ...{
            ServletContext servletContext = actionServlet.getServletContext();
            WebApplicationContext wac = 
                                   WebApplicationContextUtils.getRequiredWebApplicationContext(servletContext);
            this.petStore = (PetStoreFacade) wac.getBean("petStore");
        }
    }

    protected PetStoreFacade getPetStore() ...{
        return petStore;
    }

}

继承Action类,action每次初始化时自动调用setServlet方法,这里将spring管理的bean赋给action
ServletContext servletContext = actionServlet.getServletContext();
WebApplicationContext wac = WebApplicationContextUtils.getRequiredWebApplicationContext(servletContext);
ApplicationContext可以看作为一个应用容器,org.springframework.web.context.ContextLoaderListener在web启动时初始化这个容器,将bean放在这个容器中
WebApplicationContext继承自ApplicationContext,Spring提供了一个WebApplicationContextUtils类，可以方便的取出WebApplicationContext，只要把ServletContext传入就可以了
得到WebApplicationContext实例,可以用getBean方法来获取bean

2>
AccountActionForm acctForm = (AccountActionForm) form;
实例化AccountActionForm,它继承与BaseActionForm
BaseActionForm类继承org.apache.struts.action.ActionForm,重写了父类的validate方法,用于校验处理

public ActionErrors validate(ActionMapping mapping, HttpServletRequest request) ...{
    ActionErrors actionErrors = null;
    ArrayList errorList = new ArrayList();
    doValidate(mapping, request, errorList);
    request.setAttribute("errors", errorList);
    if (!errorList.isEmpty()) ...{
      actionErrors = new ActionErrors();
      actionErrors.add(ActionErrors.GLOBAL_ERROR, new ActionError("global.error"));
    }
    return actionErrors;
}

再回到AccountActionForm,只要继承BaseActionForm,然后重写doValidate(mapping, request, errorList)方法,就可以自由定义校验规则.