500 Request processing failed； nested exception is java.lang.NullPointerException

类型 异常报告

消息 Request processing failed; nested exception is java.lang.NullPointerException

描述 服务器遇到一个意外的情况，阻止它完成请求。

 

报错原因：这种报错原因很多，主要是某一个变量为空，所以教主要的解决方法流程和例题

报错详细信息：

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException
	org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:986)
	org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:881)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:652)
	org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:855)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
	org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
	org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
根本原因。

java.lang.NullPointerException
	com.supermarket.controller.UserController.login(UserController.java:31)
	java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	java.base/java.lang.reflect.Method.invoke(Method.java:564)
	org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209)
	org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136)
	org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
	org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:871)
	org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:777)
	org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
	org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991)
	org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
	org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:978)
	org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:881)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:652)
	org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:855)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
	org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
	org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)

出错的地方:

本文地址：https://blog.csdn.net/weixin_44812560/article/details/111052629