Spring——集成Web环境()

简介

　　Spring集合Web环境：通过Listener自动创建ApplicationContext，并放入ServletContext中。通过这样不用每次都new ApplicationContext()

操作

　　1. web.xml中配置ContextLoaderListener监听器，监听Web启动

  contextConfigLocation
  classpath:applicationContext.xml




  org.springframework.web.context.ContextLoaderListener

　　2.使用WebApplicationContextUtils获得应用上下文对象ApplicationContext

WebApplicationContext webApplicationContext = WebApplicationContextUtils.getWebApplicationContext(request.getServletContext());

　使用

  
  <context-param>
    <param-name>contextConfigLocationparam-name>
    <param-value>classpath:applicationContext.xmlparam-value>
  context-param>

  
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListenerlistener-class>
  listener>

@WebServlet(value = "/userController")
public class UserController extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request,response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        WebApplicationContext webApplicationContext = WebApplicationContextUtils.getWebApplicationContext(request.getServletContext());
    }
}