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This article introduces the knowledge of "how to use Servlet container and Context". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

The Servlet container starts to create a lot of objects, such as Servlet,filter,listener,spring, and so on, so how do you use them?

The following describes how to use spring's IOC container in Servlet (or Filter, or Listener). By default, the Servlet container creates a spring container object, and when it is injected into Servlet Context, the Servlet Context object is injected into the session object, the session object is injected into the request object, and the request object is injected into the Servlet object. (in fact, it is not very standard injection, passing parameters, or directly paying the value of the attribute). Spring container objects can be obtained through layers of dependencies.

WebApplicationContext webApplicationContext = WebApplicationContextUtils.

GetWebApplicationContext (request.getSession () .getServletContext ())

So you can fetch the Web Application Context object directly from Servlet Context:

WebApplicationContext webApplicationContext = (WebApplicationContext)

ServletContext.getAttribute (WebApplicationContext.

ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE)

In fact, the WebApplication ContextUtils.getWebApplicationContext method is implemented using the above code, and it is recommended to use the above static method

Note: when using web Application Context.getBean ("ServiceName"), the previous mandatory conversion uses the interface, and if you use the implementation class, you will report a type conversion error. Such as:

LUserService userService = (LUserService)

WebApplicationContext.getBean ("userService")

That's all for "how to use Servlet Container and Context". Thank you for reading. If you want to know more about the industry, you can follow the website, the editor will output more high-quality practical articles for you!

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