已采納回答 / 六月熊
可能原因：1，命名空間不一致；2，setter和getter方法沒寫；你的錯誤提示寫了在調用Login方法時資源未知，并提示出錯在UsersDAOImpl.java:22 處，樓主仔細檢查一下這里是否有疏漏吧。
2016-09-12
struts-2.5.2中,沒有servletcontext,其實只要有servletrequest和servletresponse就夠了,session和application可以通過以下方式在需要的時候進行獲取;
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/> <!-- 鏄劇ず琛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/> <!-- 鏄劇ず琛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)
