求救

下面是错误代码，请大侠帮忙
org.apache.jasper.JasperException: Exception in JSP: /admin/bookDeleteConfirm.jsp:2926:    <jsp:useBean id="bookDao" class="dao.BookDao"/>
27:     <%String bookNO=request.getParameter("bookNO");
28:       Book book=bookDao.findbook(bookNO);
29:       if(book.getBookName()==null){%>
30:       <jsp:forward page="admin/manageBook.jsp"/>
31:     <%}%> 
32:     root causejava.lang.NullPointerException
org.apache.jsp.admin.bookDeleteConfirm_jsp._jspService(bookDeleteConfirm_jsp.java:85)
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)