Servlet用request.setAttribute()向jsp传递数据时得到的数据是0和null

Question

jsp代码

    <%
        List<Student> students = (List<Student>)request.getAttribute("students");
        for(Student student:students){
    %>
        <tr>
            <td><%=student.getSno() %></td>
            <td><%=student.getSname() %></td>
            <td><%=student.getSage() %></td>
            <td><%=student.getSsex() %></td>
        </tr>
    <%}%>

</table>

servlet代码

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
StudentService studentService = new StudentService();
List students = studentService.queryAllStudent();
request.setAttribute("students", students);
request.getRequestDispatcher("index.jsp").forward(request, response);
}

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    doGet(request, response);
}

学号	姓名	年龄	性别

Answer 1

既然要请求转发,那就让转发到的端去处理,而不是在发生转发请求的端去处理;

你的错误原因是这样的------>>>
请求转发到一个端(jsp网页),由于请求转发时的特性------->>转发之时会将转发request域中的内容清空, 然后再将请求转发到一个端(jsp网页),那这时候jsp再从转发的请求中获取信息,只能获得默认值 所以学号和年龄为 0姓名和性别为null ;
有两种解决方案:
1,将数据放入到session域中,然后请求转发,从session域中去取数据;
2,将转发方式改为include,这时候从request域中取数据就有了;

欢迎采纳!