这个是输入界面
<form action="login.jsp" method="post" form col-md-12 center-block">
<div class="form-group">
<input type="text" id="username" class="form-control input-lg" placeholder="用户名">
</div>
<div class="form-group">
<input type="password" id="password" class="form-control input-lg" placeholder="登录密码">
</div>
<div class="form-group">
<select name="shenfen">
<option value="User_Company">公司管理人员</option>
<option value="User_Admin">管理员</option>
</select>
</div>
<div class="form-group">
<input type="text" id="CheckId" class="form-control input-lg" placeholder="验证码">
</div>
<div class="form-group">
<input type="submit" value="登录">
</a>
<span><a href="#">找回密码，请联系超级管理员[张三]</a></span><!--弹出联系管理员界面-->
</div>
</form>
这个是处理界面：
<%
try{
String username = request.getParameter("username");
String password = request.getParameter("password");
//String shenfen = request.getParameter("select");
Company_DAO ucd = new Company_DAO();
Company c = ucd.login(username, password);
session.setAttribute("loginUser", c);
response.sendRedirect("Company/main_company.jsp");
return;
}catch(MsgException e){
%>
<h2 style="color:red">发生错误：<%=e.getMessage() %></h2>
<%
}
%>
运行之后出现的错误：
HTTP Status 500 - An exception occurred processing JSP page /login.jsp at line 21
type Exception report
message An exception occurred processing JSP page /login.jsp at line 21
description The server encountered an internal error that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: An exception occurred processing JSP page /login.jsp at line 21
18: String password = request.getParameter("password");
19: //String shenfen = request.getParameter("select");
20: Company_DAO ucd = new Company_DAO();
21: Company c = ucd.login(username, password);
22: session.setAttribute("loginUser", c);
23: response.sendRedirect("Company/main_company.jsp");
24: return;
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:521)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:430)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
root cause
java.lang.NullPointerException
hnu_Project_Dao.Company_DAO.login(Company_DAO.java:47)
org.apache.jsp.login_jsp._jspService(login_jsp.java:77)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:388)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
求救啊！大神们！
