spring+hibernate+struts问题


调用DAO方法是报如下错：
java.lang.NullPointerException
test5.OrderheadDAO.findById(OrderheadDAO.java:49)
org.apache.jsp.index_jsp._jspService(index_jsp.java:64)
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:334)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)