老师，我跟着你的视频一步步敲的代码，但是今天我在11:20的时候跑起来有login页面，但是填写提交的时候后台报空指针的错误，我找了好久实在不知道怎么去定位错误在哪里，你看哪里出问题的可能比较大，我再去看看

2018-03-25 20:11:15.929  WARN 13440 --- [nio-8081-exec-2] o.a.shiro.authc.AbstractAuthenticator    : Authentication failed for token submission [org.apache.shiro.authc.UsernamePasswordToken - admin, rememberMe=false].  Possible unexpected error? (Typical or expected login exceptions should extend from AuthenticationException).

java.lang.NullPointerException: null

at com.mmall.demo2.AuthRealm.doGetAuthenticationInfo(AuthRealm.java:58) ~[classes/:na]

at org.apache.shiro.realm.AuthenticatingRealm.getAuthenticationInfo(AuthenticatingRealm.java:571) ~[shiro-core-1.4.0.jar:1.4.0]

at org.apache.shiro.authc.pam.ModularRealmAuthenticator.doSingleRealmAuthentication(ModularRealmAuthenticator.java:180) ~[shiro-core-1.4.0.jar:1.4.0]

at org.apache.shiro.authc.pam.ModularRealmAuthenticator.doAuthenticate(ModularRealmAuthenticator.java:267) ~[shiro-core-1.4.0.jar:1.4.0]

at org.apache.shiro.authc.AbstractAuthenticator.authenticate(AbstractAuthenticator.java:198) ~[shiro-core-1.4.0.jar:1.4.0]

at org.apache.shiro.mgt.AuthenticatingSecurityManager.authenticate(AuthenticatingSecurityManager.java:106) [shiro-core-1.4.0.jar:1.4.0]

at org.apache.shiro.mgt.DefaultSecurityManager.login(DefaultSecurityManager.java:274) [shiro-core-1.4.0.jar:1.4.0]

at org.apache.shiro.subject.support.DelegatingSubject.login(DelegatingSubject.java:260) [shiro-core-1.4.0.jar:1.4.0]

at com.mmall.demo2.TestController.loginUser(TestController.java:34) [classes/:na]

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_121]

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_121]

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]

at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]

at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209) [spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) [spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) [spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:870) [spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:776) [spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) [spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) [spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) [spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:978) [spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:881) [spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at javax.servlet.http.HttpServlet.service(HttpServlet.java:661) [tomcat-embed-core-8.5.28.jar:8.5.28]

at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:855) [spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) [tomcat-embed-core-8.5.28.jar:8.5.28]

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) [tomcat-embed-core-8.5.28.jar:8.5.28]

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.28.jar:8.5.28]

at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) [tomcat-embed-websocket-8.5.28.jar:8.5.28]

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.28.jar:8.5.28]

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.28.jar:8.5.28]

at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449) [shiro-web-1.4.0.jar:1.4.0]

at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365) [shiro-web-1.4.0.jar:1.4.0]

at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90) [shiro-core-1.4.0.jar:1.4.0]

at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83) [shiro-core-1.4.0.jar:1.4.0]

at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:387) [shiro-core-1.4.0.jar:1.4.0]

at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362) [shiro-web-1.4.0.jar:1.4.0]

at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125) [shiro-web-1.4.0.jar:1.4.0]

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.28.jar:8.5.28]

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.28.jar:8.5.28]

at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) [spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.28.jar:8.5.28]

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.28.jar:8.5.28]

at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) [spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.28.jar:8.5.28]

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.28.jar:8.5.28]

at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) [spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.28.jar:8.5.28]