eclipse运行报错500，org.apache.jasper.JasperException: java.lang.NullPointerException

Question

问题遇到的现象和发生背景

项目里面的add.jsp和edit.jsp都能运行，只有这个index.jsp，文件运行报错，

问题相关代码，请勿粘贴截图

运行结果及报错内容

HTTP Status 500 - java.lang.NullPointerException

type Exception report

message java.lang.NullPointerException

description The server encountered an internal error that prevented it from fulfilling this request.

exception
org.apache.jasper.JasperException: java.lang.NullPointerException
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:555)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:476)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

root cause
java.lang.NullPointerException
pers.contact.dao.BaseDao.executeQuery(BaseDao.java:59)
pers.contact.service.ContactService.GetAllContact(ContactService.java:20)
org.apache.jsp.index_jsp._jspService(index_jsp.java:137)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:438)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

note The full stack trace of the root cause is available in the Apache Tomcat/8.0.29 logs.

)

我的解答思路和尝试过的方法

我想要达到的结果

Answer 1

pers.contact.dao.BaseDao.executeQuery(BaseDao.java:59)
BaseDao类的59行代码抛出的空指针异常，看看这行代码。