servlet中三个重要的对象request，session，application在页面间的传值有着重要作用，其作用域如下：
三大作用域对照表.png
具体的代码测试如下：
@WebServlet("/scope01")
public class TestScope01 extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setAttribute("name", "zhangsan");
//request.getRequestDispatcher("scope02").forward(request, response);
request.getSession().setAttribute("age", 25);
request.getServletContext().setAttribute("address", "天河区");
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
@WebServlet("/scope02")
public class TestScope02 extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Object name = request.getAttribute("name");
System.out.println(name);
Object age = request.getSession().getAttribute("age");
System.out.println(age);
Object address = request.getServletContext().getAttribute("address");
System.out.println(address);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
