qq_32727079 2016-08-27 14:56 采纳率: 0%
浏览 2902

本人初学者，写了一个servlet报空指针异常，求大神帮忙

java.lang.NullPointerException at com.nwnu.loginServlet.LoginServlet.doGet(LoginServlet.java:29) at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:522) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1095) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:672) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1502) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1458) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:745)

  • 写回答

4条回答 默认 最新

  • devmiao 2016-08-27 15:55
    关注

    http://www.oschina.net/question/1010589_146991

    评论

报告相同问题？

悬赏问题

  • ¥15 delta降尺度计算的一些细节，有偿
  • ¥15 Arduino红外遥控代码有问题
  • ¥15 数值计算离散正交多项式
  • ¥30 数值计算均差系数编程
  • ¥15 redis-full-check比较 两个集群的数据出错
  • ¥15 Matlab编程问题
  • ¥15 训练的多模态特征融合模型准确度很低怎么办
  • ¥15 kylin启动报错log4j类冲突
  • ¥15 超声波模块测距控制点灯，灯的闪烁很不稳定，经过调试发现测的距离偏大
  • ¥15 import arcpy出现importing _arcgisscripting 找不到相关程序