1.获取ServletContext对象

• 两种方式
  1.通过request获取
  ServletContext servletContext = request.getServletContext();
  2.通过HttpServlet获取
  ServletContext servletContext = this.getServletContext();
• 代码

@WebServlet("/servletContextDemo1")
public class ServletContextDemo1 extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//通过request获取ServletContext servletContext = request.getServletContext();//通过HttpServlet获取ServletContext servletContext1 = this.getServletContext();}
}

2.功能

2.1 获取MIME对象

servletContext.getMimeType();

• 步骤
  1.通过HttpServlet获取ServletContext对象
  2.定义文件名称
  3.获取MIME类型

@WebServlet("/servletContextDemo1")
public class ServletContextDemo1 extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//通过HttpServlet获取ServletContext servletContext = this.getServletContext();//定义文件名称String filename = "a.jpg";//获取MIME类型String mimeType = servletContext.getMimeType(filename);System.out.println(mimeType);}
}

• 结果：image/jpeg

2.2 域对象:共享数据

1. setAttribute(string name,object value)
2. getAttribute( string hame)
3. removeAttribute(string name)

• 作用范围
  Servletcontext对象范围:所有用户所有请求的数据

2.3 获取文件真实路径（服务器路径）

• String getRealPath(String path)