获取初始化参数

<!--可以配置一些web应用初始化参数-->
    <context-param>
        <param-name>url</param-name>
        <param-value>jdbc:mysql://localhost:3306/mybatis</param-value>
    </context-param>

protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//读取初始化参数
        ServletContext context = this.getServletContext();
        String url = (String)context.getInitParameter("url");
        resp.getWriter().println(url);
    }

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转发和重定向

doGet(){
...
//        RequestDispatcher requestDispatcher = context.getRequestDispatcher("");//转发的路径
//        requestDispatcher.forward(req,resp);//实现转发
        context.getRequestDispatcher("").forward(req, resp);
...
}

转发(上)和重定向(下)

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读取资源文件

poperties
classpath: java和resource路径

classpath路径
读取资源文件

思路: 需要一个文件流;