高手进来看看，这是什么异常

[FlowerJunjie]

HTTP Status 500 -

--------------------------------------------------------------------------------

type Exception report

message

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

exception

org.apache.jasper.JasperException
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:370)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:291)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.runtime.JspRuntimeLibrary.include(JspRuntimeLibrary.java:966)
org.apache.jsp.index_jsp._jspService(org.apache.jsp.index_jsp:66)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:322)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:291)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)


root cause

java.lang.NullPointerException
org.apache.jsp.header_jsp._jspService(org.apache.jsp.header_jsp:65)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:322)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:291)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.runtime.JspRuntimeLibrary.include(JspRuntimeLibrary.java:966)
org.apache.jsp.index_jsp._jspService(org.apache.jsp.index_jsp:66)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:322)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:291)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)


note The full stack trace of the root cause is available in the Apache Tomcat/5.5.9 logs.


--------------------------------------------------------------------------------

Apache Tomcat/5.5.9

[FlowerJunjie]

如何解决，谢谢

[kevinliuu]

空指针

header.jsp

[zbo]

java.lang.NullPointerException
org.apache.jsp.header_jsp._jspService(org.apache.jsp.header_jsp:65)
空指针异常

[hefei0603]

你有没有直接强制转化可能为空的值？

[FlowerJunjie]

我是直接copy的教程上的例子
程序应该没问题
只是我连不上数据库
打了sp3的补丁还是不行
记得学习的时候补丁还要打补丁，唉，放下时间久了，不怎么记得了
有谁知道java连接数据库系统具体怎么设置
有没有专门的文章，推荐下
网上搜了好多，没找到

[hefei0603]

1。教程也不一定就绝对正确，上面少几个字母，打错1，2个字母都是可能出现的。
2。连接不上数据库，那么与数据库相关的数据就会报空指针错误。
3。连数据库看你用哪种驱动，连什么数据库了。不然怎么知道该告诉你什么！

[FlowerJunjie]

String sDBDriver = "com.microsoft.jdbc.sqlserver.SQLServerDriver";
String url="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=InfoSite";

这是数据库连接

[hefei0603]

这个要到网上下驱动的，而且版本太低的还不行。。。。
我直接用JAVA自带的驱动连的，不过需要建立ODBC数据源。