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登陆案例_BeanUtils基本使用自己BeanUtils介绍

时间:2022-12-05 22:00:11浏览次数:55  
标签:username req User 案例 登陆 loginUser BeanUtils user

登陆案例_BeanUtils基本使用自己BeanUtils介绍

BeanUtils工具类,简化数据封装:

  导入jar包:commons-beanutils-1.8.0.jar

LoginServlet:

@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.设置编码
        req.setCharacterEncoding("utf-8");
        //2.获取请求参数
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        //3.封装user对象
        User loginUser = new User();
        loginUser.setUsername(username);
        loginUser.setPassword(password);

        //2.获取所有请求参数
//        Map<String, String[]> map = req.getParameterMap();
//        //3.创建user对象
//        User loginUser = new User();
//        //3.2使用BeanUtils封装
//        try {
//            BeanUtils.populate(loginUser, map);
//        } catch (IllegalAccessException e) {
//            throw new RuntimeException(e);
//        } catch (InvocationTargetException e) {
//            throw new RuntimeException(e);
//        }

        //4.调用UserDao的login方法
        UserDao dao = new UserDao();
        User user = dao.login(loginUser);

        //5.判断user
        if (user == null){
            //登陆失败
            req.getRequestDispatcher("/failServlet").forward(req, resp);
        }else {
            //登陆成功
            //存储数据
            req.setAttribute("user", user);
            //转发
            req.getRequestDispatcher("/successServlet").forward(req, resp);
        }
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doGet(req, resp);
    }
}

 

 

 

用于封装JavaBean的

  1、JavaBean:标准的Java类

    1、要求:

      1、类必须被public修饰

      2、必须提供空参的构造器

      3、成员变量必须使用private修饰

      4、提供公共setter和getter方法

    2、功能:封装数据

  2、概念:

    成员变量:

    属性:setter和getter方法截取后的产物

      例如:getUsername() --> Username  --> username

  3、方法:

    1、setProperty();

    2、getProperty();

    3、populate(Object obj,Map map):将map集合的键值对信息,封装到对应的JavaBean对象中

public class BeanutilsTest {
    @Test
    public void test(){
        User user = new User();
        try {
            BeanUtils.setProperty(user,"username","张三");
            String username = BeanUtils.getProperty(user, "username");
            System.out.println(username);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        }
        System.out.println(user);
        
    }
}

 

标签:username,req,User,案例,登陆,loginUser,BeanUtils,user
From: https://www.cnblogs.com/qihaokuan/p/16953675.html

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