很简单的SSH问题 java.lang.NullPointerException 在线等！！！
login.jsp

Java code

 <s:form action="register" method="post">  <s:textfield name="user.username" label="用户名"/>  <s:password name="user.password" label="密码"/>  <s:submit value="注册"/>  <s:reset value="重填"/>  </s:form>

struts.xml

XML code

<package name="default" extends="struts-default"><action name="register" class="action.RegisterAction"><result name="success">/success.jsp</result></action>

ApplicationContext.xml

XML code

<bean id="userDao" class="Realized.UserDaoHibernate" /><bean id="User" class="bean.User"/><bean id="registerAction" class="action.RegisterAction"><property name="user" ref="User"/><property name="userDao" ref="userDao"/></bean>

RegisterAction.java

Java code

package action;import javax.annotation.Resource;import bean.User;import com.opensymphony.xwork2.ActionSupport;import dao.UserDao;public class RegisterAction extends ActionSupport {    /**     *      */    private static final long serialVersionUID = 1L;    private UserDao userDao;    public UserDao getUserDao() {        return userDao;    }    @Resource    public void setUserDao(UserDao userDao) {        this.userDao = userDao;    }    private User user;    public User getUser() {        return user;    }    @Resource    public void setUser(User user) {        this.user = user;    }    public String execute() throws Exception    {       userDao.saveUser(user);       return SUCCESS;    }}

[解决办法]
private User user;
把这个属性及相关的方法从Action中删除掉。
[解决办法]
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
改成
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>*.action</url-pattern>
</filter-mapping>
试一下吧，好像被拦截器拦截了
[解决办法]
我在奇怪这样写为什么IDE没给你错误提示，userDao.saveUser(user); 变量要先初始化再使用，给private User user 初始化为：private User user = null试试;