<bean name="/shop/signonForm.do"
class="org.springframework.web.servlet.mvc.ParameterizableViewController">
<property name="viewName" value="SignonForm"/>
</bean>

<bean name="/shop/signon.do"
class="org.springframework.samples.jpetstore.web.spring.SignonController"> ①

<property name="petStore" ref="petStore"/> ②

</bean>

public ModelAndView handleRequest(HttpServletRequest request,
HttpServletResponse response) throws Exception {
String username = request.getParameter("username");
String password = request.getParameter("password");
Account account = this.petStore.getAccount(username, password);
if (account == null) {
return new ModelAndView("Error", "message",
"Invalid username or password. Signon failed.");
}
else {
UserSession userSession = new UserSession(account);
PagedListHolder myList = new PagedListHolder(this.petStore.getProductListByCategory(account.getFavouriteCategoryId()));
myList.setPageSize(4);
userSession.setMyList(myList);
request.getSession().setAttribute("userSession", userSession);

String forwardAction = request.getParameter("forwardAction");

if (forwardAction != null) {
response.sendRedirect(forwardAction);
return null;
}
else {
return new ModelAndView("index");
  }
}
}

<c:if test="${!empty signonForwardAction}">
<input type="hidden" name="forwardAction" value="<c:url value="${signonForwardAction}"/>"/>
</c:if>

<property name="petStore" ref="petStore"/>

<c:if test="${!empty signonForwardAction}">
<input type="hidden" name="forwardAction" value="<c:url value="${signonForwardAction}"/>"/>
</c:if>

public class SignonInterceptor extends HandlerInterceptorAdapter {

  public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
      throws Exception {
    UserSession userSession = (UserSession) WebUtils.getSessionAttribute(request, "userSession");
    if (userSession == null) {
      String url = request.getServletPath();
      String query = request.getQueryString();
      ModelAndView modelAndView = new ModelAndView("SignonForm");
      if (query != null) {
        modelAndView.addObject("signonForwardAction", url+"?"+query);
      }
      else {
        modelAndView.addObject("signonForwardAction", url);
      }
      throw new ModelAndViewDefiningException(modelAndView);
    }
    else {
      return true;
    }
  }
}

3. I want to have a tutorial which can show me nuts and bolts, one piece at a time. A combined petstore is good, but not good for beginners. So I wrote the document to fill in the gap.

老王卖瓜，自卖自夸

王婆卖瓜，自卖自夸

public class UserHomeController implements Controller
{
private String viewFilename;
public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response)
throws Exception
{
return new ModelAndView(this.getViewFilename());
}
public void setViewFilename(String name) { this.viewFilename = name; }
public String getViewFilename() { return this.viewFilename; }
}