getSession().getAttribute(“.”) -> null
getSession().getAttribute(“.”) -> null
提问于 2017-08-15 16:13:50
我创建了一个signIn servlet：
@WebServlet(
name = "SignInServlet",
description = "check email & pass",
urlPatterns = {"/authorization_signin"}
)
public class SignInServlet extends javax.servlet.http.HttpServlet {
public SignInServlet(){
}
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws javax.servlet.ServletException, IOException {
request.setCharacterEncoding("UTF-8");
UserDataSet user = new UserDataSet();
SignInModel modelSignIn = new SignInModel();
user.setEmail(request.getParameter("email"));
user.setPassword(request.getParameter("password"));
user = modelSignIn.doSignIn(user);
if (request.getSession().getAttribute("loggedUser") == null) {
if (user != null) {
request.getSession().setAttribute("loggedUser", user); request.getRequestDispatcher("authorization.jsp").forward(request, response);
response.setStatus(HttpServletResponse.SC_OK);
} else {
request.setAttribute("errorMessage", "Email or password is incorrect");
request.getRequestDispatcher("index.jsp").forward(request, response);
response.setStatus(HttpServletResponse.SC_OK);
}
}
}
@Override
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException{
response.setContentType("text/html; charset=utf-8");
response.setStatus(HttpServletResponse.SC_NOT_FOUND);
}
}当用户登录时，servlet将他重定向到"authorization.jsp“
<body>
<%
if (request.getSession().getAttribute("loggedUser") != null){
UserDataSet user = (UserDataSet) request.getSession().getAttribute("loggedUser");
System.out.println("In author :" + request.getSession().getAttribute("loggedUser"));
%>
<h1> Hello <%= user.getFirstName() %> <%= user.getLastName() %>!</h1>
<h2>AUTORIZED!</h2>
<a href="/authorization_logout">Log Out</a>
<%
}
else {
%>
<h1>GO HOME</h1>
<%
}
%>
</body>然后浏览器显示此页面和数据，以便在用户中签名。
如果写入URL "localhost:8080“并转到"index.jsp"，则在"authorization.jsp”上再次写入
筛选检查会话：
@WebFilter(filterName = "LoginFilter")
public class LoginFilter implements Filter {
public void destroy() {
}
public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws ServletException, IOException {
HttpServletRequest httpRequest = (HttpServletRequest) req;
HttpServletResponse httpResponse = (HttpServletResponse) resp;
System.out.println("Enter filter");
System.out.println("Filter session: " + httpRequest.getSession(false).getAttribute("loggedUser"));
UserDataSet user = (UserDataSet) httpRequest.getSession(false).getAttribute("loggedUser");
if (user != null) {
System.out.println("CHAIN");
chain.doFilter(req, resp);
} else {
httpResponse.sendRedirect("/");
System.out.println("Not signin");
}
}
public void init(FilterConfig config) throws ServletException {
}
}getSession().getAttribute("loggedUser")返回null为什么？
下一个文本:如果我登录并servlet打开"authorization.jsp"，那么尝试在任何*.jsp上抛出*.jsp，在那里将检查会话，结果将是null
怎么了？
回答 2
Stack Overflow用户
回答已采纳
发布于 2017-08-16 08:26:12
我的朋友帮我在stackoverflow上找到了这个问题的答案
如果您使用request.getSession().setAttribute在会话中放置了某些内容，则必须从会话中读取它，而不是从请求中读取。试试<%= session.getAttribute("test") %>
Stack Overflow用户
发布于 2020-04-28 22:43:33
我用过
<%= request.getParameter("loggedUser") %>由于某种原因，当我使用request.getSession().getAttribute("loggedUser")时，我在java日志中看到了1，我还在相同的代码中观察到了request.getParameter工作的情况，至少当值通过查询字符串传递并且“未检查的或不安全的操作”从日志中消失时。因此，在我看来，这是一个解决这个问题的办法。
1
_index__jsp.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/45696968
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