ServletContext对象原理

ServletContext即是一种上下文

ServletContext可以通过保存一些东西来建立多个servlet中的链接

• 在A servlet中向ServletContext传入一些数据

public class servletContext extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        ServletContext context = this.getServletContext();//Servlet的上下文
        String username="张三";
        context.setAttribute("name",username);//将一个数据保存在ServletContext，键值对
        
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doPost(req, resp);
    }
}

• B servlet可以读取ServletContext中的数据

public class getContext extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        ServletContext context = this.getServletContext();

        String  name = (String)context.getAttribute("name");

        resp.setContentType("text/html");
        resp.setCharacterEncoding("utf-8");
        resp.getWriter().print("名字"+name);

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doPost(req, resp);
    }
}

• 结果如下