请求servlet操作成功后，在JSP页面弹出提示框

应用环境：

点击前台页面，执行某些操作。后台action/servlet 执行后，返回处理结果（成功、失败、原因、状态等）信息。在前台jsp进行弹窗显示，alert();

后台处理代码：（把要提示的数据放到session中。）

if(flag){
                message="分类修改成功";
                req.getSession().setAttribute("message", message);
                resp.sendRedirect(req.getContextPath()+"/servlet/categoryListServlet");
            }else{
                message="分类修改失败";
                req.getSession().setAttribute("message", message);
            }

前台处理代码：

<%
	String mess=(String)session.getAttribute("message");
	if("".equals(mess)  && mess==null){
		
	}

 else{%>
 	<script type="text/javascript">
		alert("<%=mess%>");
</script>

	session.setAttribute("message", "");  
<% }%>

 上面的例子是把信息放入整个会话session中，这个session对整个用户请求都有效，在Session不过期时间之内都有效，其实有时候是要分别来对待的，比如新增、删除、修改、登陆成功等操作，我们操作成功后，是要重定向到目标页面，重定向request作用域不能延伸，所以我们要用Session存放弹框信息，但如果是转发到目标页面，我们就可以用request了

登陆实例：

index.jsp:

 1 <%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>
 2 <%
 3 String path = request.getContextPath();
 4 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
 5 %>
 6 
 7 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 8 <html>
 9   <head>
10     <base href="<%=basePath%>">
11     
12     <title>My JSP 'index.jsp' starting page</title>
13   </head>
14   
15   <body>
16     This is my JSP page. <br>
17     <%
18     Object message = request.getAttribute("message");
19     if(message!=null && !"".equals(message)){
20 
21  %>
22      <script type="text/javascript">
23          alert("<%=message%>");
24      </script>
25  <%} %>
26     <form action="<%=request.getContextPath() %>/servlet/checkLogin" method="post">
27         <input type="text" name="username" value=""/><br/>
28         <input type="submit" name="login" value="提交"/>
29     </form>
30   </body>
31 </html>

CheckLogin.java（servlet）:

 1 package servlet;
 2 import java.io.IOException;
 3 import java.net.InetSocketAddress;
 4 import java.util.concurrent.Executor;
 5 import javax.servlet.ServletException;
 6 import javax.servlet.http.HttpServlet;
 7 import javax.servlet.http.HttpServletRequest;
 8 import javax.servlet.http.HttpServletResponse;
 9 import javax.servlet.http.HttpSession;
10 public class CheckLogin extends HttpServlet{
11     @Override
12     protected void doGet(HttpServletRequest req, HttpServletResponse resp)
13             throws ServletException, IOException {
14         doPost(req, resp);
15     }
16     @Override
17     protected void doPost(HttpServletRequest req, HttpServletResponse resp)
18             throws ServletException, IOException {
19         String username = req.getParameter("username");
20         HttpSession session=req.getSession();
21         if(username.equals("admin")){
22             //登陆成功，我是重定向到其它页面，所以这里我要用session才可以把成功的信息传递给count.jsp
23             session.setAttribute("sucess", "登陆成功！");
24             resp.sendRedirect(req.getContextPath()+"/count.jsp");
25         }else{
26             //登陆失败，我有的是转发，转发request作用域是连续的，所以我这里可以用request传递失败的信息给JSp页面
27             req.setAttribute("message", "登陆失败！");
28             req.getRequestDispatcher("/index.jsp").forward(req, resp);
29         }
30     }
31     @Override
32     protected void service(HttpServletRequest req, HttpServletResponse resp)
33             throws ServletException, IOException {
34         super.service(req, resp);
35     }
36     
37 }

web.xml

  <servlet>
      <servlet-name>checkLogin</servlet-name>
      <servlet-class>servlet.CheckLogin</servlet-class>
  </servlet>
  <servlet-mapping>
      <servlet-name>checkLogin</servlet-name>
      <url-pattern>/servlet/checkLogin</url-pattern>
  </servlet-mapping>

count.jsp(登陆成功目标页)

 1 <%@ page language="java" contentType="text/html; charset=UTF-8"
 2     pageEncoding="UTF-8"%>
 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 4 <html>
 5 <head>
 6 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 7 <title>Insert title here</title>
 8 </head>
 9 <body>
10 <%
11     Object message = session.getAttribute("sucess");
12     if(message!=null && !"".equals(message)){
13 
14  %>
15      <script type="text/javascript">
16          alert("<%=message%>");
17      </script>
18  <%} %>
19 hello word!
20 </body>
21 </html>

 

posted @ 2016-09-09 09:36  sincoolvip  阅读(57807)  评论(4)  编辑  收藏  举报