我已经被这个苦恼的问题折磨好半天了。。高手们帮我看看问题出在哪了总是空指针异常可是我检查了很仔细了还是没看出来哪里不对。急~~~~
登陆页面

  <tr>
        <td width="70" align="center">用户名:</td>
        <td><input name="user.username" type="text" class="id" style="width:160px;"/></td>
      </tr>
      <tr>
        <td width="70" align="center">密&nbsp;&nbsp;码:</td>
        <td><input name="user.password" type="password" class="id" style="width:160px;"/></td>
      </tr>

UserDAO

public class UserDAO {
    private JdbcTemplate jt;

    public JdbcTemplate getJt() {
        return jt;
    }

    public void setJt(JdbcTemplate jt) {
        this.jt = jt;
    }
    
    public User getUser(User user){
        String sql="select count(*) from user where username='"
            + user.getUsername() + "' and password='" + user.getPassword()
            + "'";
        
        int tt=jt.queryForInt(sql);
        if(tt>0)
            return user;    
        else
            return null;
    }

UserService

public class UserService {
     private UserDAO userDAO;

    public UserDAO getUserDAO() {
        return userDAO;
    }

    public void setUserDAO(UserDAO userDAO) {
        this.userDAO = userDAO;
    }
    
    public boolean isLogin(User user){
        
        if(userDAO.getUser(user)!=null){    
            return true;
        }
        return false;
    }

UserAction

public class UserAction extends ActionSupport {
    
    private UserService userService;
    private User user;
        public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }
        public UserService getUserService() {
        return userService;
    }

    public void setUserService(UserService userService) {
        this.userService = userService;
    }
public String execute() throws Exception{
        
        if(userService.isLogin(user)){
            ActionContext context = ActionContext.getContext();
            Map session = context.getSession();
            session.put("user", user);
            System.out.println("判断ACTION已经执行");
            return "success";
            
         }
        else
        {
                        return "input";
        }

        }

折磨写我拿不到这个a值是什么原因

qq_42179110

2个回复