JSP中没有任何错误，但出现下面的异常可能是程序哪一块出现了问题？（在线等待）

[bread213]

A Servlet Exception Has Occurred
Exception Report:
javax.servlet.ServletException
at org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:481)
at jsp.myjsp._0002fjsp_0002fmyjsp_0002fInputScore_0002ejspInputScore_jsp_2._jspService(_0002fjsp_0002fmyjsp_0002fInputScore_0002ejspInputScore_jsp_2.java:158)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:119)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.jasper.servlet.JspServlet$JspServletWrapper.service(JspServlet.java:184)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:328)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:407)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:215)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:251)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:977)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:196)
at org.apache.catalina.valves.ValveBase.invokeNext(ValveBase.java:242)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:464)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:975)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2041)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161)
at org.apache.catalina.valves.ValveBase.invokeNext(ValveBase.java:242)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:414)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:975)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:159)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:977)
at org.apache.catalina.connector.http.HttpProcessor.process(HttpProcessor.java:818)
at org.apache.catalina.connector.http.HttpProcessor.run(HttpProcessor.java:897)
at java.lang.Thread.run(Thread.java:484)

Root Cause:
java.lang.NullPointerException
at jsp.myjsp._0002fjsp_0002fmyjsp_0002fInputScore_0002ejspInputScore_jsp_2._jspService(_0002fjsp_0002fmyjsp_0002fInputScore_0002ejspInputScore_jsp_2.java:57)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:119)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.jasper.servlet.JspServlet$JspServletWrapper.service(JspServlet.java:184)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:328)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:407)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:215)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:251)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:977)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:196)
at org.apache.catalina.valves.ValveBase.invokeNext(ValveBase.java:242)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:464)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:975)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2041)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161)
at org.apache.catalina.valves.ValveBase.invokeNext(ValveBase.java:242)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:414)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:975)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:159)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:977)
at org.apache.catalina.connector.http.HttpProcessor.process(HttpProcessor.java:818)
at org.apache.catalina.connector.http.HttpProcessor.run(HttpProcessor.java:897)
at java.lang.Thread.run(Thread.java:484)

[ewang_365]

servlet的毛病。大概是你没有把servlet包放到环境变量中去。

[bread213]

我写的是JSP，它不是自动转换成SERVLET吗？
我的环境变量中除了classpath的jdk外，另外设置了JAVA_HOME和TOMCAT_HOME，这有错吗？
其它的JSP程序可以运行呀！
继续求救！

[weidegong]

Root Cause:
java.lang.NullPointerException at ...

数组、字符串、记录集为空，但是你却使用了这个变量；找找吧，一定有

[bread213]

加上一个异常抛出是不是就可以使用了？

[chen_guo_quan]

NullPointerException

应该是试图调用值为null的对象方法，

因为一个对象值为null时，

是不允许任何对该对象方法调用的.

最好声明对象时，就初始化该对象！

你出现的问题我想可能是：你从另一个页面接收参数，然后

对参数进行操作，有时候，正确得到参数，所以正常。

但有时间页面得不到参数时，但出现以上至命错误！

好好找找。