Spring IOC简单登录案例

  private String username;
    private String password;

两个成员，一个用户名，一个密码

@Repository
public class UserDao {
    private final String USERNAME="admin";
    private final String PASSWORD="admin";

    public User queryByName(String username){
        User user = null;
        if (!USERNAME.equals(username)){
            return user;
        }
        user = new User();
        user.setUsername(USERNAME);
        user.setPassword(PASSWORD);
        return user;
    }

}

dao层一般是连接数据库的到这里为了简单化，直接定义数据了

这层是自己定义的一个类用来返回提示信息的

 private int resultCode = 1;
    private String resultMsg = "登录成功";

两个成员变量，一个是状态码1代表登录成功0代表登录失败，一个是提示信息

@Service
public class UserService {
    @Resource
    private UserDao userDao;

    public MessageModle login(String username,String password){
        MessageModle message = new MessageModle();
        //用户名不能为空
        if (username==null||"".equals(username.trim())){
            message.setResultCode(0);
            message.setResultMsg("用户名不能为空");
            return message;
        }
        //密码不能为空
        if (password==null||"".equals(password.trim())){
            message.setResultCode(0);
            message.setResultMsg("密码不能为空");
            return message;
        }
        User user = userDao.queryByName(username);
        //用户名不正确
        if (user==null){
            message.setResultCode(0);
            message.setResultMsg("用户名不正确");
            return message;
        }
        //密码不正确
        if (!user.getPassword().equals(password)){
            message.setResultCode(0);
            message.setResultMsg("密码不正确");
            return message;
        }
        return message;
    }
}

service层依赖与dao层，从dao层拿数据库信息

@Controller
public class UserController {
    @Resource
    private UserService userService;

    public MessageModle login(String username,String password){
        return userService.login(username,password);
    }

}

   @Test
    public void test(){
        ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("spring.xml");
        UserController userController = ac.getBean("userController", UserController.class);
        MessageModle login = userController.login("admin", "");
        System.out.println(login);
    }