Question

我有这段代码，它返回一个NullPointerException。怎么了？

public static void createMultiLogin(HttpServletRequest httpRequest)
{


        HttpSessionManager sessionManager =(HttpSessionManager) httpRequest.getAttribute(HttpSessionManager.class.getName());
        String alias = httpRequest.getParameter("userdetails");
        System.out.println("Inside createMultiLogin "+alias);
        @SuppressWarnings("unchecked")
        SessionRepository<Session> sessionRepository =(SessionRepository<Session>)httpRequest.getAttribute(SessionRepository.class.getName());


        for(Map.Entry<String, String> entry : sessionManager.getSessionIds(httpRequest).entrySet()) {
                String aliasId = entry.getKey();
                String sessionId = entry.getValue();

                Session storedSession = sessionRepository.getSession(sessionId);
                HttpSession httpSession = httpRequest.getSession(false);
                    if(storedSession.getAttribute("ssouserid") != null)
                    {
                            httpSession.setAttribute("ssouserid", storedSession.getAttribute("ssouserid"));
                    }


                System.out.println("printing from the multilogin class "+aliasId +" : "+sessionId);
        }

        if(alias == null || "".equals(alias.trim()))
        {
                alias = sessionManager.getNewSessionAlias(httpRequest);
        }
        httpRequest.setAttribute("alias",alias);
}

Stacktrace：

org.springframework.web.servlet.HandlerExecutionChain.applyPreHandle（HandlerExecutionChain.java:134）在org.springframework.web.servlet.DispatcherServlet.doDispatch（DispatcherServlet.java:954）在org.springframework.web.servlet.DispatcherServlet.doService（DispatcherServlet.java:893）在org.springframework.web.servlet.FrameworkServlet.processRequest（FrameworkServlet.java:970）在org.springframework.web.servlet.FrameworkServlet.doGet（FrameworkServlet.java:861）在javax.servlet.http.HttpServlet.service（HttpServlet.java:635）在org.springframework.web.servlet.FrameworkServlet.service（FrameworkServlet.java:846）在javax.servlet.http.HttpServlet.service（HttpServlet.java:742）在org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:231）在org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:166）在org.apache.tomcat.websocket.server.WsFilter.doFilter（WsFilter.java:52）在org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:193）在org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:166）在org.apache.catalina.core.StandardWrapperValve.invoke（StandardWrapperValve.java:198）在org.apache.catalina.core.StandardContextValve.invoke（StandardContextValve.java:96）在org.apache.catalina.authenticator.AuthenticatorBase.invoke（AuthenticatorBase.java:493）在org.apache.catalina.core.StandardHostValve.invoke（StandardHostValve.java:140）在org.apache.catalina.valves.ErrorReportValve.invoke（ErrorReportValve.java:81）在org.apache.catalina.valves.AbstractAccessLogValve.invoke（AbstractAccessLogValve.java:650）在org.apache.catalina.core.StandardEngineValve.invoke（StandardEngineValve.java:87）在org.apache.catalina.connector.CoyoteAdapter.service（CoyoteAdapter.java:342）在org.apache.coyote.http11.Http11Processor.service（Http11Processor.java:800）在org.apache.coyote.AbstractProcessorLight.process（AbstractProcessorLight.java:66）在org.apache.coyote.AbstractProtocol $ ConnectionHandler.process（AbstractProtocol.java:800）在org.apache.tomcat.util.net.NioEndpoint $ SocketProcessor.doRun（NioEndpoint.java:1471）在org.apache.tomcat.util.net.SocketProcessorBase.run（SocketProcessorBase.java:49）在java.util.concurrent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1149）在java.util.concurrent.ThreadPoolExecutor $ Worker.run（ThreadPoolExecutor.java:624）在org.apache.tomcat.util.threads.TaskThread $ WrappingRunnable.run（TaskThread.java:61）在java.lang.Thread.run（Thread.java:748）

HttpSessionManager getSessionIds（）返回nullpointerException

0 个答案: