[英]Servlet crashes when logging in with a registered user, but not when logging in automatically after registering an account
這是一個大學實驗室。 我已經被困了三天了。 我正在使用Google App Engine和Java構建圖像查看器網站。 我制作了一個具有登錄功能的網頁。 用戶可以在歡迎頁面上注冊一個帳戶或登錄。如果我注冊了一個新帳戶，就沒有問題，將保存用戶數據，將Cookie添加到http響應中，然后用戶可以進入下一頁上傳和查看他們在注冊帳戶時選擇的類別中的圖像。 但是，如果我嘗試以已經具有帳戶的用戶身份登錄，則應用程序在成功登錄后由於NullPointerException崩潰而崩潰，我無法弄清楚出了什么問題。
除了保存和讀取數據庫外，注冊和登錄的過程相同。
這是我的歡迎頁面：
<%@ page import="com.google.appengine.api.blobstore.BlobstoreServiceFactory" %>
<%@ page import="com.google.appengine.api.blobstore.BlobstoreService" %>
<%@ page import="com.blobtest.UserManager" %>
<%@ page import="com.blobtest.UserDatastore" %>
<%@ page import="com.google.appengine.api.datastore.Entity" %>
<%@ page import="java.util.List" %>
<%
BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();
UserManager userManager = new UserManager();
UserDatastore dataStore = new UserDatastore();
Cookie cookie = null;
Cookie[] cookies = null;
cookies = request.getCookies();
if(cookies != null){
System.out.println("");
System.out.println("============ From WELCOME.JSP =================");
System.out.println("");
System.out.println("Found Cookies!!");
for(int i = 0; i < cookies.length; i++){
cookie = cookies[i];
System.out.println("");
System.out.println("Name: " + cookie.getName());
System.out.println("Value: " + cookie.getValue());
System.out.println("Domain: " + cookie.getDomain());
}
System.out.println("");
System.out.println("============ From WELCOME.JSP =================");
System.out.println("");
}
%>
<html>
<head>
<title>Welcome</title>
<link rel="StyleSheet" type="text/css" href="Style.css" />
</head>
<body>
<h1>Welcome to the Picture Gallery!</h1>
<p>To log in enter your email and password and press "Login", to register enter your email, the password you want and select a role from the menu and press "Login"</p>
<form action="usermanager" method="post">
<label>E-Mail:</label>
<input name="username" type="text" size="30" maxlength="2048" />
<label>Password:</label>
<input name="password" type="password" size="30" maxlength="2048" />
<label>Role:</label>
<select name="register_role">
<%
List<Entity> registerRoles = dataStore.getRoles();
for(Entity role : registerRoles){
out.println("<option>" + role.getProperty("role") + "</option>");
}
%>
</select>
<input type="submit" value="Login">
</form>
<h1>Gallery Viewer</h1>
<p>Select a gallery from the menu below and press "Go" to view it</p>
<form action="/serve" method="get">
<select name="role">
<%
List<Entity> roles = dataStore.getRoles();
for(Entity role : roles){
out.println("<option>" + role.getProperty("role") + "</option>");
}
%>
</select>
<input type="submit" value="Go">
</form>
</body>
</html>
這是我的UserManager類：
package com.blobtest;
import java.io.IOException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.google.appengine.api.datastore.Entity;
public class UserManager extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 8824378069546886214L;
public final String ROLE_SOLDIER = "soldier";
public final String ROLE_PROGRAMMER = "programmer";
public final String ROLE_SINGER = "singer";
public final String ROLE_FOOTBALLER = "footballer";
public final String COOKIE_PROPERTY_ROLE = "role";
public final String COOKIE_PROPERTY_USER = "verifieduser";
public final String COOKIE_APP_DOMAIN = "ImageViewer.se";
private UserDatastore datastore;
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
datastore = new UserDatastore();
checkCookies(request);
String email = request.getParameter("username");
String password = request.getParameter("password");
String role = request.getParameter("register_role");
Entity user = datastore.selectUser(email);
/*
* If the database returns a user, check the password matches, otherwise
* register the user
*/
if (user != null) {
if (password.equals(user.getProperty("password"))) {
message("REGISTERED USER FOUND:", true, 0);
message("user: " + user.getProperty("email") + "; Password: "
+ user.getProperty("password"), false, 0);
// request.getSession().setAttribute("loggedInUser", userName);
Cookie cookie = new Cookie(this.COOKIE_PROPERTY_ROLE, user
.getProperty("role").toString());
message("UserManager: New Cookie created with role: "
+ user.getProperty("role").toString(), false, 0);
cookie.setMaxAge(300); // -1 = persist for the duration of the
// session; 0 = remove cookie; value > 0
// = time in seconds.
response.addCookie(cookie);
Cookie userCookie = new Cookie(this.COOKIE_PROPERTY_USER, user
.getProperty("email").toString());
message("UserManager: New Cookie created with verifieduser: "
+ user.getProperty("email").toString(), true, 1);
userCookie.setMaxAge(300); // -1 = persist for the duration of
// the session; 0 = remove cookie;
// value > 0 = time in seconds.
response.addCookie(userCookie);
dispatch(request, response, "/loggedin.jsp");
} else {
message("Passwords don't match, invalidating session", true, 0);
message("", true, 1);
request.getSession().invalidate(); // need to dispose of cookies
// here, not currently using
// sessions
dispatch(request, response, "/welcome.jsp");
}
} else {
datastore.addUser(email, password, role);
message("NEW USER ADDED:", true, 0);
Cookie cookie = new Cookie(this.COOKIE_PROPERTY_ROLE, role);
message("UserManager: New Cookie created with role: " + role,
false, 0);
cookie.setMaxAge(300); // -1 = persist for the duration of the
// session; 0 = remove cookie; value > 0 =
// time in seconds.
response.addCookie(cookie);
Cookie userCookie = new Cookie(this.COOKIE_PROPERTY_USER, email);
message("UserManager: New Cookie created with verifieduser: "
+ email, true, 1);
userCookie.setMaxAge(300); // -1 = persist for the duration of the
// session; 0 = remove cookie; value > 0
// = time in seconds.
response.addCookie(userCookie);
dispatch(request, response, "/register.jsp");
}
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException {
}
protected void dispatch(HttpServletRequest request,
HttpServletResponse response, String page)
throws javax.servlet.ServletException, java.io.IOException {
RequestDispatcher dispatcher = getServletContext()
.getRequestDispatcher(page);
dispatcher.forward(request, response);
}
private void checkCookies(HttpServletRequest request) {
Cookie cookie = null;
Cookie[] cookies = null;
cookies = request.getCookies();
if (cookies != null) {
message("Found Cookies!!", true, 0);
for (int i = 0; i < cookies.length; i++) {
cookie = cookies[i];
message("Name: " + cookie.getName(), false, 0);
message("Value: " + cookie.getValue(), false, 0);
message("Domain: " + cookie.getDomain(), false, 0);
}
message("", true, 1);
}
}
/**
* Formats the message and message wrapper
*
* @param message
* The message to print
* @param includeWrapper
* true to include header/footer labels
* @param position
* if includeWrapper is true, then set 0 for header 1 for footer,
* otherwise set 0.
*/
private void message(String message, boolean includeWrapper, int position) {
if (includeWrapper) {
if (position == 0) {
System.out.println("");
System.out
.println("==========From USERMANAGER===================");
System.out.println("");
System.out.println(message);
} else {
System.out.println(message);
System.out.println("");
System.out
.println("========== From USERMANAGER ===================");
System.out.println("");
}
} else {
System.out.println(message);
}
}
}
我的“登錄成功”和“注冊成功”頁面完全相同，它們只是重定向到下面的Uploader.jsp頁面：
<%@ page import="com.google.appengine.api.blobstore.BlobstoreServiceFactory" %>
<%@ page import="com.google.appengine.api.blobstore.BlobstoreService" %>
<%@ page import="com.blobtest.UserManager" %>
<%@ page import="com.blobtest.UserDatastore" %>
<%@ page import="com.google.appengine.api.datastore.Entity" %>
<%@ page import="java.util.List" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<% //taglib xmlns:h="http://java.sun.com/jsf/html"prefix="h" %>
<%
BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();
UserManager userManager = new UserManager();
UserDatastore dataStore = new UserDatastore();
Cookie[] cookies = request.getCookies();
Cookie userCookie = null;
boolean ok = false;
for(int i = 0; i < cookies.length; i++){
if(cookies[i].getName().equals(userManager.COOKIE_PROPERTY_USER)){
if(cookies[i].getValue() != null){
ok = true;
}
}else if(cookies[i].getName().equals(userManager.COOKIE_PROPERTY_ROLE)){
userCookie = cookies[i];
}
}
if(!ok){
System.out.println("Request failed, number of cookies found: " + cookies.length + ", redirecting to welcome.jsp");
for(int i = 0; i < cookies.length; i++){
System.out.println("Name: " + cookies[i].getName() + ", Value: " + cookies[i].getValue());
}
RequestDispatcher dispatcher = getServletContext()
.getRequestDispatcher("/welcome.jsp");
dispatcher.forward(request, response);
}
%>
<html>
<head>
<title>Upload Test</title>
<link rel="StyleSheet" type="text/css" href="style.css" />
</head>
<body>
<form action="<%= blobstoreService.createUploadUrl("/upload") %>" method="post" enctype="multipart/form-data">
<input type="text" name="description">
<input type="file" name="myFile">
<input type="submit" value="Submit">
</form>
<form action="/usermanager" method="post" enctype="multipart/form-data">
</form>
<form action="/serve" method="get">
<select name="role">
<%
if(userCookie != null) out.println("<option>" + userCookie.getValue() + "</option>");
%>
</select>
<input type="submit" value="Go">
</form>
<%
Cookie cookie2 = null;
Cookie[] cookies2 = null;
// Get an array of Cookies associated with this domain
cookies2 = request.getCookies();
if( cookies2 != null ){
out.println("<h2> Found Cookies Name and Value</h2>");
for (int i = 0; i < cookies.length; i++){
cookie2 = cookies2[i];
out.print("Name : " + cookie2.getName( ) + ", ");
out.print("Value: " + cookie2.getValue( )+" <br/>");
}
}else{
out.println("<h2>No cookies founds</h2>");
}
%>
<a href="/logout.jsp">Click to Log Out</a>
</body>
</html>
上面的頁面是應用程序崩潰的地方。 如果我嘗試使用以前注冊的用戶登錄，則會出現以下錯誤（包括一些來自UserManager的打印輸出）：
Retreiving user: paul@email.com, 1234, programmer
==========From USERMANAGER===================
REGISTERED USER FOUND:
user: paul@email.com; Password: 1234
UserManager: New Cookie created with role: programmer
UserManager: New Cookie created with verifieduser: paul@email.com
========== From USERMANAGER ===================
mar 30, 2014 12:53:53 EM com.google.apphosting.utils.jetty.JettyLogger warn
WARNING: /uploader.jsp
java.lang.NullPointerException
at org.apache.jsp.uploader_jsp._jspService(uploader_jsp.java:76)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
at com.google.appengine.tools.development.PrivilegedJspServlet.access$101(PrivilegedJspServlet.java:23)
at com.google.appengine.tools.development.PrivilegedJspServlet$2.run(PrivilegedJspServlet.java:61)
at java.security.AccessController.doPrivileged(Native Method)
at com.google.appengine.tools.development.PrivilegedJspServlet.service(PrivilegedJspServlet.java:58)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
at com.google.appengine.api.socket.dev.DevSocketFilter.doFilter(DevSocketFilter.java:74)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:127)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:63)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:125)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectRequest(DevAppServerModulesFilter.java:366)
at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectModuleRequest(DevAppServerModulesFilter.java:349)
at com.google.appengine.tools.development.DevAppServerModulesFilter.doFilter(DevAppServerModulesFilter.java:116)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:98)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:487)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:547)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
==========From USERMANAGER===================
NEW USER ADDED:
UserManager: New Cookie created with role: soldier
UserManager: New Cookie created with verifieduser: paul3@email.com
========== From USERMANAGER ===================
mar 30, 2014 12:54:32 EM com.google.appengine.api.datastore.dev.LocalDatastoreService$PersistDatastore persist
INFO: Time to persist datastore: 56 ms
如您在上面看到的，添加新用戶時我沒有收到任何錯誤，它會繼續按原樣前進到uploader.jsp頁面，我可以上傳和查看圖片而沒有任何問題。 任何指針將不勝感激。
for (int i = 0; i < cookies.length; i++){ ，代碼行中的check cokkies可能為null 。
<%
Cookie cookie2 = null;
Cookie[] cookies2 = null;
// Get an array of Cookies associated with this domain
cookies2 = request.getCookies();
if( cookies2 != null ){
out.println("<h2> Found Cookies Name and Value</h2>");
for (int i = 0; i < cookies.length; i++){ //Here cookies may be null
cookie2 = cookies2[i];
out.print("Name : " + cookie2.getName( ) + ", ");
out.print("Value: " + cookie2.getValue( )+" <br/>");
}
}else{
out.println("<h2>No cookies founds</h2>");
}
%>
這個答案可能會幫助您如何使用jstl在jsp中使用/檢索cokkies ，您可以通過這種方式避免一些NullPointerException 。
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即使憑據正確，Spring-security 也不會登錄用戶
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