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JSP出错Caused by: java.lang.NullPointerException

JSP出错Caused by: java.lang.NullPointerException

AquanGeek 2017-08-27 19:00:13
<%@ page language="java" import="java.util.*,java.text.*" contentType="text/html; charset=utf-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">        <title>My JSP 'userinfo.jsp' starting page</title>     <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0">     <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> -->    <style type="text/css">  .title{   width: 30%;    background-color: #CCC;   font-weight: bold;  }  .content{      width:70%;      background-color: #CBCFE5;  }     </style>    </head>    <body>    <h1>用户信息</h1>    <hr>    <center>     <jsp:useBean  id="regUser" class="entity.Users" scope="session"/>        <table width="600" cellpadding="0" cellspacing="0" border="1">        <tr>          <td class="title">用户名:</td>          <td class="content">&nbsp;<jsp:getProperty name="regUser" property="username"/></td>        </tr>        <tr>          <td class="title">密码:</td>          <td class="content">&nbsp;<jsp:getProperty name="regUser" property="mypassword"/></td>        </tr>        <tr>          <td class="title">性别:</td>          <td class="content">&nbsp;<jsp:getProperty name="regUser" property="gender"/></td>        </tr>        <tr>          <td class="title">E-mail:</td>          <td class="content">&nbsp;<jsp:getProperty name="regUser" property="email"/></td>        </tr>        <tr>          <td class="title">出生日期:</td>          <td class="content">&nbsp;            <%                SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日");               String date = sdf.format(regUser.getBirthday());                           %>             <%=date%>          </td>        </tr>        <tr>          <td class="title">爱好:</td>          <td class="content">&nbsp;            <%                String[] favorites = regUser.getFavorites();               for(String f:favorites)               {            %>                <%=f%> &nbsp;&nbsp;            <%                }            %>          </td>        </tr>        <tr>          <td class="title">自我介绍:</td>          <td class="content">&nbsp;<jsp:getProperty name="regUser" property="introduce"/></td>        </tr>        <tr>          <td class="title">是否介绍协议:</td>          <td class="content">&nbsp;<jsp:getProperty name="regUser" property="flag"/></td>        </tr>     </table>    </center>  </body></html>错误提示:严重: Servlet.service() for servlet jsp threw exceptionjava.lang.NullPointerException at org.apache.jsp.userinfo_jsp._jspService(userinfo_jsp.java:212) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:443) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329) at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:726) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:469) at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:394) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:311) at servlet.RegServlet.doPost(RegServlet.java:103) at javax.servlet.http.HttpServlet.service(HttpServlet.java:648) at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:474) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:783) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:789) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1437) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) 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)org.apache.jasper.JasperException: An exception occurred processing JSP page /userinfo.jsp at line 7572:           <td class="content">&nbsp;73:             <% 74:                String[] favorites = regUser.getFavorites();75:                for(String f:favorites)76:                {77:             %>78:                 <%=f%> &nbsp;&nbsp;Stacktrace: at org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:584) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:481) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329) at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:726) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:469) at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:394) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:311) at servlet.RegServlet.doPost(RegServlet.java:103) at javax.servlet.http.HttpServlet.service(HttpServlet.java:648) at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:474) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:783) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:789) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1437) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) 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)Caused by: java.lang.NullPointerException at org.apache.jsp.userinfo_jsp._jspService(userinfo_jsp.java:212) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:443) ... 37 more
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上面说了,空指针异常,一般情况下是,让一个 为空的对象(即不存在的)调用方法。 <% 

74:                String[] favorites = regUser.getFavorites();

75:                for(String f:favorites)

76:                {

77:             %>

   

不知道你上面的对象是否存在,如 regUser


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反对 回复 2017-08-27
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