Validação de Login

<%@ page import="java.util.*" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
 
<jsp:useBean id="validaAdmin" class="dao.admin.TestaLoginAdmin" />
<c:set var="admin" value="${validaAdmin.testaLogin(request)}" />
<c:set var="redireciona" value="${validaAdmin.redireciona(request)}" />
 
<c:choose>
<c:when test="${admin != null}">          
             ${admin.nome};
    </c:when>
<c:otherwise>
             ${redireciona};
    </c:otherwise>
</c:choose>

package dao.admin;
 
import model.Admin;
 
import java.io.*;  
import javax.servlet.*;  
import javax.servlet.http.*;
 
public class TestaLoginAdmin 
{ 
public Admin testaLogin(HttpServletRequest request) throws ServletException, IOException 
{
HttpSession sessao = request.getSession();
 
Admin admin = (Admin) sessao.getAttribute("admin");
        
if(admin != null)
{
return admin;
}
return null;
}
 
public void redireciona(HttpServletResponse response) throws ServletException, IOException
{
response.sendRedirect("index.jsp");
}
}

HTTP Status 500 - org.apache.jasper.JasperException: An exception occurred processing JSP page /_global/testaAdmin.jsp at line 5
 
 
type Exception report
 
message org.apache.jasper.JasperException: An exception occurred processing JSP page /_global/testaAdmin.jsp at line 5
 
description The server encountered an internal error that prevented it from fulfilling this request.
 
exception
org.apache.jasper.JasperException: org.apache.jasper.JasperException: An exception occurred processing JSP page /_global/testaAdmin.jsp at line 5
 
2: <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
3: 
4: <jsp:useBean id="validaAdmin" class="dao.admin.TestaLoginAdmin" />
5: <c:set var="admin" value="${validaAdmin.testaLogin(request)}" />
6: <c:set var="redireciona" value="${validaAdmin.redireciona(request)}" />
7: 
8: <c:choose>
 
 
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:555)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:461)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
 
 
root cause
org.apache.jasper.JasperException: An exception occurred processing JSP page /_global/testaAdmin.jsp at line 5
 
2: <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
3: 
4: <jsp:useBean id="validaAdmin" class="dao.admin.TestaLoginAdmin" />
5: <c:set var="admin" value="${validaAdmin.testaLogin(request)}" />
6: <c:set var="redireciona" value="${validaAdmin.redireciona(request)}" />
7: 
8: <c:choose>
 
 
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:574)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:476)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.jasper.runtime.JspRuntimeLibrary.include(JspRuntimeLibrary.java:934)
org.apache.jsp.admin.principal_jsp._jspService(principal_jsp.java:89)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:438)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
 
 
root cause
org.apache.jasper.el.JspELException: /_global/testaAdmin.jsp(5,0) '${validaAdmin.testaLogin(request)}' java.lang.NullPointerException
org.apache.jasper.el.JspValueExpression.getValue(JspValueExpression.java:123)
org.apache.jsp._005fglobal.testaAdmin_jsp._jspx_meth_c_005fset_005f0(testaAdmin_jsp.java:161)
org.apache.jsp._005fglobal.testaAdmin_jsp._jspService(testaAdmin_jsp.java:121)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:438)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.jasper.runtime.JspRuntimeLibrary.include(JspRuntimeLibrary.java:934)
org.apache.jsp.admin.principal_jsp._jspService(principal_jsp.java:89)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:438)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
 
 
root cause
java.lang.NullPointerException
dao.admin.TestaLoginAdmin.testaLogin(TestaLoginAdmin.java:13)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
javax.el.BeanELResolver.invoke(BeanELResolver.java:165)
org.apache.jasper.el.JasperELResolver.invoke(JasperELResolver.java:147)
org.apache.el.parser.AstValue.getValue(AstValue.java:159)
org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:184)
org.apache.jasper.el.JspValueExpression.getValue(JspValueExpression.java:115)
org.apache.jsp._005fglobal.testaAdmin_jsp._jspx_meth_c_005fset_005f0(testaAdmin_jsp.java:161)
org.apache.jsp._005fglobal.testaAdmin_jsp._jspService(testaAdmin_jsp.java:121)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:438)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.jasper.runtime.JspRuntimeLibrary.include(JspRuntimeLibrary.java:934)
org.apache.jsp.admin.principal_jsp._jspService(principal_jsp.java:89)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:438)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
 
 
note The full stack trace of the root cause is available in the Apache Tomcat/8.0.22 logs.
 
 
Apache Tomcat/8.0.22