你说了一些错误。
您不妨比较服务器/JSP和ASP。 NET, no t You?
Servlets vs IHttpHandler
从概念上讲,它们是相同的。 它们也是两个接口。 其配置有所不同(WEB.xml VS Web.config或.ashx文档),但其切入点“几乎”相同。
Servlet:
Init()
Service()
Destroy()
IHttphandler:
ProcessRequest() <<--- does all the things
IsReusable {get;} <<--- optional
JSP vs ASP.NET pages
如果你界定了一种构造,或者推翻了<代码>InitializeFramework()方法,那么,你就有一个起点(或者至少是一分点,可以把执行放在几乎一切的想象中),但不是切入点。
Page class implements IHttpHandler, if you allow me some Java syntax in .NET world, but you don t see anything. You might want to go deeper into page life cycle as linked by other users. Basically explaining, Page encapsulates its complete life cycle in events, that resemble clock ticks when you work with VHDL components.
Execution is not concurrent as it seems, but since you can t know the exact order in which controls will raise the same event, you can go as the VHDL example in which you can t read the value of a registry before the next clock tick.
There are several events: here are the most important in their execution order
- Init: page is initialized, GET, POST and cookie data are available. If you override, then you should initialize your webapp context (ie setup db connections)
- Load (PreLoad and LoadComplete too): page loads the UI data and restores, if needs to, the state of controls displayed on the page. If you set up DB connections in init, you shouldn t use them before PreLoad to be sure you don t get an exception. The same applies to sequence PreLoad->Load->LoadComplete.
- DataBind: data-bound controls load data from database, file or whatever (ie. tables get the data to display)
- Validation: if you use validators, their business logic is processed to determine whether the page is valid or not. No further explaining here
- Postback processing: if you click a button, then its server-side code is executed
- PreRender (and PreRenderComplete): the page is getting ready for being rendered into HTML. Usually stores internal data into a collection named ViewState which I won t explain any further here. Usually you would finalize some data-related operations and/or decide whether to render or not some controls on the page according to the page s state. For example, if you have a CAPTCHA and the user solved the puzzle, you won t render it again
- Render: not actually a programmatic event, but the page gets rendered to HTML
- Dispose: resources get freed, as occurs with
Destroy in Java
