java 请问这个servlet为什么会报错 求解

似乎是因为写的Student类没有录进去，请问如何解决该情况？

img

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.*;

public class StudentServlet extends HttpServlet
{
public void doPost(HttpServletRequest httpservletrequest, HttpServletResponse httpservletresponse)
throws ServletException, IOException
{
httpservletrequest.setCharacterEncoding("utf-8");

    httpservletresponse.setContentType("text/html;charset=utf-8");
    
    PrintWriter printwriter = httpservletresponse.getWriter();

    String Name             = httpservletrequest.getParameter("Name");
    String Age                 = httpservletrequest.getParameter("Age");
    String Sex                 = httpservletrequest.getParameter("Sex");
    String College          = httpservletrequest.getParameter("College");
    String Grade            = httpservletrequest.getParameter("Grade");
    String Cclass           = httpservletrequest.getParameter("Cclass");

    String IsPartyMember    = httpservletrequest.getParameter("IsPartyMember");
    
    String SelectedCourse = "";   
    for(int i=1;i<=7;i++){
        String Course = "Course" + i;
        if(httpservletrequest.getParameter(Course)!=null)
            SelectedCourse += "[" + httpservletrequest.getParameter(Course) + "]";
    }
                        
    Student Someone = new Student();
    Someone.setName(Name);
    Someone.setAge(Age);
    Someone.setSex(Sex);
    Someone.setCollege(College);
    Someone.setGrade(Grade);
    Someone.setCclass(Cclass);
    Someone.setIsPartyMember(IsPartyMember);
    Someone.setSelectedCourse(SelectedCourse);
    
    printwriter.println("<html>");
    printwriter.println("<head>");
    printwriter.println("<meta http-equiv=\"content-type\" content=\"text/html; charset=utf-8\" />");
    printwriter.println("<title>Success</title>");
    printwriter.println("<style type=\"text/css\">");
    printwriter.println("<!--");
    printwriter.println(".STYLE1 {");
    printwriter.println("    font-size: 24px;");
    printwriter.println("    font-weight: bold;");
    printwriter.println("    color: #000000;");
    printwriter.println("}");
    printwriter.println(".STYLE2 {");
    printwriter.println("    font-size: 36px;");
    printwriter.println("    color: #FF0000;");
    printwriter.println("}");
    printwriter.println(".STYLE3 {color: #0000FF}");
    printwriter.println(".STYLE4 {");
    printwriter.println("    font-size: 24px;");
    printwriter.println("    font-weight: bold;");
    printwriter.println("    color: #0000FF;");
    printwriter.println("}");
    printwriter.println(".STYLE36 {color: #330066; font-size: 16px; font-weight: bold; }");
    printwriter.println(".STYLE39 {font-size: 16px; color: #000000; font-weight: bold; }");
    printwriter.println("-->");
    printwriter.println("</style>");
    printwriter.println("</head>");
    printwriter.println("<body bgcolor=\"00FFFF\">");
    printwriter.println("<h1 align=\"center\" class=\"STYLE2\">Success!</h1>");
    printwriter.println("<p class=\"STYLE1 STYLE3\">111</p>");
    printwriter.println("<table width=\"410\" height=\"319\" cellspacing=\"10\">");
    printwriter.println("  <tr>");
    printwriter.println("    <th width=\"167\" align=\"left\" scope=\"row\"><span class=\"STYLE36\">222</span></th>");
    printwriter.println("    <td width=\"207\"><span class=\"STYLE39\">" + Someone.getName() + "</span></td>");
    printwriter.println("  </tr>");
    printwriter.println("  <tr>");
    printwriter.println("    <th align=\"left\" scope=\"row\"><span class=\"STYLE36\">333</span></th>");
    printwriter.println("    <td><span class=\"STYLE39\">" + Someone.getAge() + "</span></td>");
    printwriter.println("  </tr>");
    printwriter.println("  <tr>");
    printwriter.println("    <th align=\"left\" scope=\"row\"><span class=\"STYLE36\">444</span></th>");
    printwriter.println("    <td><span class=\"STYLE39\">" + Someone.getSex() + "</span></td>");
    printwriter.println("  </tr>");
    
    printwriter.println("  <tr>");
    printwriter.println("    <th align=\"left\" scope=\"row\"><span class=\"STYLE36\">555</span></th>");
    printwriter.println("    <td><span class=\"STYLE39\">" + Someone.getCollege() + "</span></td>");
    printwriter.println("  </tr>");
    
    printwriter.println("  <tr>");
    printwriter.println("    <th align=\"left\" scope=\"row\"><span class=\"STYLE36\">666</span></th>");
    printwriter.println("    <td><span class=\"STYLE39\">" + Someone.getCclass() + "</span></td>");
    printwriter.println("  </tr>");

    printwriter.println("  <tr>");
    printwriter.println("    <th align=\"left\" scope=\"row\"><span class=\"STYLE36\">777</span></th>");
    printwriter.println("    <td><span class=\"STYLE39\">" + Someone.getIsPartyMember() + "</span></td>");
    printwriter.println("  </tr>");
    printwriter.println("  <tr>");
    printwriter.println("    <th align=\"left\" scope=\"row\"><span class=\"STYLE36\">888</span></th>");
    printwriter.println("    <td><span class=\"STYLE39\">" + Someone.getSelectedCourse() + "</span></td>");
    printwriter.println("  </tr>");
    printwriter.println("</table>");
    printwriter.println(" <p align=\"left\" class=\"STYLE4\">999 </p>");
    printwriter.println("</body>");
    printwriter.println("</html>");
    
}

}

你不要在cmd中去运行啊，这个是需要依赖tomcat的。