求助：JSP运行报空指针

如题，日志显示org.apache.jsp.index2_jsp._jspService(index2_jsp.java:187)org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)javax.servlet.http.HttpServlet.service(HttpServlet.java:717)org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
index2_jsp.java文件的187行是  out.print(user.getUId() );但是user.getUId() 这个值是得到了的，为什么还会报这个错？？？？？？