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                        /后端開發(fā)
                        
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                        /JAVA遇見HTML——JSP篇

出現(xiàn)這個錯誤是怎么回事呢，老師

An?exception?occurred?processing?JSP?page?/details.jsp?at?line?41
org.apache.jasper.JasperException:?An?exception?occurred?processing?JSP?page?/details.jsp?at?line?41

38:?????????????????????PetDAO?petDao?=?new?PetDAO();??
39:?????????????????????
40:?????????????????????
41:?????????????????????Pet?pet?=?petDao.getPetByPid(Integer.parseInt(request.getParameter("pid")));?
42:?????????????????????if(pet!=?null)??
43:?????????????????????{??
44:?????????????????????


Stacktrace:
	org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:574)
	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)