本人最近利用struts2+ibatis+spring框架搭建web项目,需要写一个登录页面。众所周知,需要把JSP中输入的用户名、密码传递给后台action处理,判断用户名密码是否正确。其中会遇到很多action接收不到JSP页面传值而无法完成交互的问题,因此可以进行一一排查:
LoginAction:
private PortalUserVO portalUserVO; private UserService userService; private static final String LOGIN_VIEW = "login"; private static final String LOGIN_SUCCESS = "success"; private static final String LOGIN_FAILED = "login"; public String doLoginView() { return LOGIN_VIEW; } public String doLogin() { String status = LOGIN_SUCCESS; String loginId = portalUserVO.getLoginId(); String loginPasswd = portalUserVO.getPasswd(); if(loginId == null || "".equals(loginId)) { errorMsg = "登录的用户名不能为空!"; status = LOGIN_VIEW; } if(loginPasswd == null || "".equals(loginPasswd)) { errorMsg = "登录的用户密码不能为空!"; status = LOGIN_VIEW; } try { PortalUserVO userVO = userService.getPortalUserByLoginId(portalUserVO.getLoginId()); if(userVO == null) { errorMsg = "用户不存在,请检查输入!"; status = LOGIN_FAILED; }else{ if(!userVO.getPasswd().equals( portalUserVO.getPasswd())){ errorMsg = "登录密码错误,请重新输入!"; status = LOGIN_FAILED; }else{ userService.updateUserLastLogin(portalUserVO); } } } catch (Exception e) { e.printStackTrace(); } return status; }
jsp页面:
<s:form id="portalUserForm" action="Login!login.action" onsubmit="return VerifyData(this)" theme="simple"> <div class="email-div"> <label for="remember"><strong class="email-label">帐号</strong></label> <input type="text" spellcheck="false" name="portalUserVO.loginId" value="" id="loginId" > </div> <div class="passwd-div"> <label for="Passwd"><strong class="passwd-label">密码</strong></label> <input type="password" name="portalUserVO.passwd" value="" id="passwd"> </div> <input name="signIn" type="submit" class="" id="signIn" value=""/> </s:form>
情况一:报以下异常:
java.lang.NullPointerException at com.hy.action.LoginAction.doLogin(LoginAction.java:21) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:404) at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:267) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:229) at com.hy.action.AuthenticationInterceptor.intercept(AuthenticationInterceptor.java:20)
我检查了很久,后来通过debug才发觉action接收到页面的登录VO为null,发现是LoginAction没有portalUserVO的get/set方法,遂加上:
public PortalUserVO getPortalUserVO() { return portalUserVO; } public void setPortalUserVO(PortalUserVO portalUserVO) { this.portalUserVO = portalUserVO; }
错误解决。
情况二:页面的name属性name="portalUserVO.xxx"一定要与action中的PortalUserVO portalUserVO一致。
情况三:是否在alias.xml配置文件中为JSP页面的vo配置过,否则会无法识别:
<sqlMap namespace="alias"> <typeAlias alias = "portalUserVO" type= "xx.entites.PortalUserVO" /> </sqlMap>
同时,entites里同样得设置get/set方法(这好像是废话……)