Question

关于jsp的空指针异常

网站昨天浏览的还好好的，今天就报错。可是我在其他服务器里面放这个网站都没问题。不知道错在哪里，请各位大侠帮帮我。

HTTP Status 500 -

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type Exception report

message

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

exception

org.apache.jasper.JasperException: Exception in JSP: /showPageImg.jsp:9

6: articleID = 1;
7: session.setAttribute("flag","ok");
8: session.setAttribute("pageNo",pageNo);
9: data.GetDefaultImg();
10: bookIssue = data.GetBookIssue();
11: bookDate = data.GetBookDate();
12: bookName = data.GetBookName();

Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:451)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:373)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)

root cause

java.lang.NullPointerException
connection.Coon.executeQuery(Coon.java:95)
getData.GetData.GetDefaultImg(getdata.java:177)
org.apache.jsp.index_jsp._jspService(index_jsp.java:295)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)

note The full stack trace of the root cause is available in the Apache Tomcat/5.5.27 logs.

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Apache Tomcat/5.5.27
今天开发的人跟我说是数据库连接池的问题，我不是很明白，∵如果网站可以运行的话，数据库连接池就应该没有设置错误啊。

Answer 1

楼上胡说。。开DEBUG吧。。你的后台报空指针了。定位一下错误的发生处