已采纳回答 / 六月熊
可能原因：1，命名空间不一致；2，setter和getter方法没写；你的错误提示写了在调用Login方法时资源未知，并提示出错在UsersDAOImpl.java:22 处，楼主仔细检查一下这里是否有疏漏吧。
2016-09-12
struts-2.5.2中,没有servletcontext,其实只要有servletrequest和servletresponse就够了,session和application可以通过以下方式在需要的时候进行获取;
HttpSession session = request.getSession();
ServletContext application = request.getServletContext();
HttpSession session = request.getSession();
ServletContext application = request.getServletContext();
2016-09-11
org.apache.jasper.JasperException: An exception occurred processing JSP page /users/Users_login.jsp at line 264
261: <input type="reset" class="btn" value="閲嶇疆"/>
262: </div>
263: <div>
264: <s:fielderror/> <!-- 鏄剧ず琛ㄥ崟楠岃瘉鐨勫嚭閿欎俊鎭�-->
</div>
<!-- end of form -->
261: <input type="reset" class="btn" value="閲嶇疆"/>
262: </div>
263: <div>
264: <s:fielderror/> <!-- 鏄剧ず琛ㄥ崟楠岃瘉鐨勫嚭閿欎俊鎭�-->
</div>
<!-- end of form -->
2016-09-09
java.lang.reflect.InvocationTargetException
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
