自学Servlet_2_servletContext
1.两种获取servletContext对象的方式

ServletContext context = this.getServletConfig().getServletContext();ServletContext context1 = this.getServletContext();

2.用context对象实现数据共享

context.setAttribute("data", "aaaaaaaaaa");

3.获取ServletContext的共享数据

context.getAttribute("data")

4.通过servletContext,获取为web应用配置的初始化参数

String url = this.getServletContext().getInitParameter("url");String username = this.getServletContext().getInitParameter("username");String password = this.getServletContext().getInitParameter("password");

  <context-param>  <param-name>url</param-name>  <param-value>jdbc:mysql://localhost:3306/test</param-value>  </context-param>    <context-param>  <param-name>username</param-name>  <param-value>root</param-value>  </context-param>    <context-param>  <param-name>password</param-name>  <param-value>root</param-value>  </context-param>

5.通过servletContext获取文件的mime类型

String filename = "1.jpg";ServletContext context = this.getServletContext();System.out.println(context.getMimeType(filename));

6.通过servletContext 实现请求转发

//servlet收到请求产生数据，然后转交给jsp显示String data = "aaaaaa";this.getServletContext().setAttribute("data", data);RequestDispatcher rd = this.getServletContext().getRequestDispatcher("/view.jsp");rd.forward(request, response);