在jsp页面调用bean报错!!!

出错如下：
Thread [http-80-1] (Suspended (exception NullPointerException))
JspServletWrapper.handleJspException(Exception) line: 436
JspServletWrapper.service(HttpServletRequest, HttpServletResponse, boolean) line: 371
JspServlet.serviceJspFile(HttpServletRequest, HttpServletResponse, String, Throwable, boolean) line: 315
JspServlet.service(HttpServletRequest, HttpServletResponse) line: 265
JspServlet(HttpServlet).service(ServletRequest, ServletResponse) line: 803
ApplicationFilterChain.internalDoFilter(ServletRequest, ServletResponse) line: 269
ApplicationFilterChain.doFilter(ServletRequest, ServletResponse) line: 188
StandardWrapperValve.invoke(Request, Response) line: 210
StandardContextValve.invoke(Request, Response) line: 174
StandardHostValve.invoke(Request, Response) line: 127
ErrorReportValve.invoke(Request, Response) line: 117
StandardEngineValve.invoke(Request, Response) line: 108
CoyoteAdapter.service(Request, Response) line: 151
Http11AprProcessor.process(long) line: 834
Http11AprProtocol$Http11ConnectionHandler.process(long) line: 640
AprEndpoint$Worker.run() line: 1286
ThreadWithAttributes(Thread).run() line: 595
不知道到如何处理