Spring start example "developing a spring framework mvc application step-by-step" analysis (1)

1. Process of loading Spring Web Module

There is a definition in Web.xml

SpringApp

Org.springframework.web.servlet.dispatcherServlet

1

SpringApp

*. htm

Therefore, DispatcherServlet is first loaded, showing log

2004-10-04

23:18

: 38,549 info [org.springframework.web.servlet.dispatcherServlet]

-

2004-10-04

23:18

: 38,699 info [org.springframework.web.servlet.dispatcherservlet]

-

What did DispatcherServlets do in the process of loading, I don't see the source code, but according to the log information judgment, it went to find / web-inf/springapp-servlet.xml

2004-10-04

23:18

: 38,839 info [org.springframework.beans.Factory.xml. XmlbeandefinitionReader] -

It then loads Beans according to the definition of springapp-servlet.xml.

I am in springapp-servlet.xml definition:

The DispatcherServlet is then done, for example, to find MultipartResolver / localeresolver / themeresolver / handleradapters / viewResolver. As for what use, I don't know now.

2, page request

I first enter a correct JSP file address, the page is displayed correctly, without any log information.

I will enter an incorrect JSP file address, and the page gives the app server's prompt information, and there is no log.

Then I will enter an incorrect HTM file address, log information:

2004-10-04 23: 43: 15,442 Warn [org.springframework.web.servlet.pagenotfound] -

o mapping for [/springapp/i.htm] in dispatcherservlet with name 'SpringApp'>

This shows that .jsp files are not processed by Spring's servlet, they will be processed by the App Server. Because the page request filtration is defined in Web.xml: *. Htm . Only the page request is .htm, App Server is handled by DispatcherServlet.

Change index.jsp to

<% @ Page session = "false"%>

<% @ taglib prefix = "c" uri = "http://java.sun.com/jstl/core"%>

<% @ taglib prefix = "FMT" URI = "http://java.sun.com/jstl/fmt"%>

<% - Redirected Because We can't set the welcome page to a Virtual URL. -%>

Added a redirect statement.

The process of SpringAppController is:

Public Class SpringAppController Implements Controller {

/ ** Logger for this class and subclasses * /

Protected final log logger = logfactory.getlog (getclass ());

Public ModlandView HandleRequest (httpservletRequest Request, HttpservletResponse Response)

Throws servletexception, ioException {

String now = (New java.util.date ()). TOSTRING ();

Logger.info ("Returning Hello View with" Now);

Return New ModelandView ("Web-INF / JSP / HELLO.JSP", "now", now)

}

}

When entering the page request /springapp/index.jsp, redirect to Hello.htm. This page request is handed over to SpringAppController processing.

Pay attention to Return New ModelandView ("Web-INF / JSP / HELLO.JSP", "now", now);

It returns a ModlandView, which should be handed over to INTERNALRESOURCEVIEWRESOLver because information appears:

2004-10-04

23:53

: 47,942 info [org.springframework.web.servlet.view.internalResourceViewResolver] -

We look at ModelandView's constructor:

Public modelAndView (View View) {}

Public modelAndView (String ViewName) {}

Public ModilandView (View View, Map Model) {}

Public ModlandView (String ViewName, Map Model) {}

Public ModilandView (View View, String Modelname, Object Modelobject) {}

Public ModlandView (String ViewName, String Modelname, Object Modelobject) {}

The above is:

Public ModlandView (String ViewName, String Modelname, Object Modelobject) {}

This shows that only one model returns in a modelandview, that is, 1 view plus 0..1 model.

Used Model in Hello.jsp:

Greetings, IT IS NOW

Thus we can see all the processes of a page request: