每日总结15

UML复习

阅读教材第一章复习UML，回答下述问题：

面向对象程序设计中类与类的关系都有哪几种？分别用类图实例说明。

1. 关联关系：单线关联、双向关联、自关联、多重性关联、聚合关系、组合关系

2. 泛化关系

3. 依赖关系

 

 

 

 

 

[实验任务二]：单一职责原则

登录模块在实际项目开发中很常见，请按照教材28页（PPT49页）利用单一职责原则重构后的类图实现这一模块。

实验要求：

1. 提交源代码和对应的数据库文件（注意将此模块保存，以备以后使用）；

样式：

 

 

 

 

 

2. 注意编程规范。

DBUtil.java

package asd;

 

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

public class DBUtil {

 

    public static String db_url = "jdbc:mysql://localhost:3306/ceshi?serverTimezone=GMT%2B8&useSSL=false";

    public static String db_user = "root";

    public static String db_pass = "NN06280055";

 

    public static Connection getConn () {

        Connection conn = null;

 

        try {

            Class.forName("com.mysql.cj.jdbc.Driver");

            conn = DriverManager.getConnection(db_url, db_user, db_pass);

        } catch (Exception e) {

            e.printStackTrace();

        }

 

        return conn;

    }//end getConn

 

    public static void close (Statement state, Connection conn) {

        if (state != null) {

            try {

                state.close();

            } catch (SQLException e) {

                e.printStackTrace();

            }

        }

 

        if (conn != null) {

            try {

                conn.close();

            } catch (SQLException e) {

                e.printStackTrace();

            }

        }

    }

 

    public static void close (ResultSet rs, Statement state, Connection conn) {

        if (rs != null) {

            try {

                rs.close();

            } catch (SQLException e) {

                e.printStackTrace();

            }

        }

 

        if (state != null) {

            try {

                state.close();

            } catch (SQLException e) {

                e.printStackTrace();

            }

        }

 

        if (conn != null) {

            try {

                conn.close();

            } catch (SQLException e) {

                e.printStackTrace();

            }

        }

    }

 

    public static void main(String[] args) throws SQLException {

        Connection conn = getConn();

        PreparedStatement pstmt = null;

        ResultSet rs = null;

        String sql ="select * from user";

        pstmt = conn.prepareStatement(sql);

        rs = pstmt.executeQuery();

        if(rs.next()){

            System.out.println("连接成功");

        }else{

            System.out.println("连接失败");

        }

    }

}

UserDao.java

package asd;

 

import java.sql.Connection;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

 

public class UserDao {

    public boolean findUser(String username, String password) {

        //准备SQL语句

        String sql = "select * from user where username ='" + username + "'";

        Connection conn= DBUtil.getConn();

        //创建语句传输对象

        Statement state = null;

        ResultSet rs= null;

        int flag=0;

        String c_password=null;

        try {

            state = conn.createStatement();

            rs = state.executeQuery(sql);

            while(rs.next()) {

                ++flag;

                c_password=rs.getString("password");

            }    if (flag == 0) {

                return false;

            }

            if (!password.equals(c_password)) {   //判断密码

                return false;

            }

    }catch (SQLException e) {

        // TODO Auto-generated catch block

        e.printStackTrace();

    }finally {

         DBUtil.close(rs, state, conn);

    }

    return true;

        }

}

 

LoginForm.java

package asd;

 

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

 

public class LoginForm extends JFrame {

    

    private static final long serialVersionUID = 1L;

    private  UserDao dao = new UserDao();

    //设置按钮组件

    

    private  JButton jb=new JButton("登录");    //添加一个登录按钮

    private JButton button=new JButton("重置");    //添加一个确定按钮

    //设置文本框组件

    private JTextField username = new JTextField();//用户名框

    private JPasswordField password = new JPasswordField();//密码框：为加密的***

    

    JLabel user_name=new JLabel("账号：");//设置左侧用户名文字

    JLabel pass_word=new JLabel("密码：");//设置左侧密码文字

    

    public void init()

    {

    /* 组件绝对位置  */

    user_name.setBounds(50, 70, 300, 25);

    pass_word.setBounds(50, 130, 200, 25);

        

    username.setBounds(110, 70, 300, 25);//设置用户名框的宽，高，x值，y值

    password.setBounds(110, 130, 300, 25);//设置密码框的宽，高，x值，y值

        

    button.setBounds(315, 225, 90, 20);//设置确定按钮的宽，高，x值，y值

    jb.setBounds(95, 225, 90, 20);//设置确定按钮的宽，高，x值，y值

        

        

    /* 组件透明化*/

    user_name.setOpaque(false);

    pass_word.setOpaque(false);

        

        

     //监听事件

    jb.addActionListener(new ActionListener(){        //为确定按钮添加监听事件

                

        @SuppressWarnings("deprecation")

        public void actionPerformed(ActionEvent arg0) {

            validate(username.getText().trim(),password.getText().trim());

        }

    });

        

            

    //重置按钮

    button.addActionListener(new ActionListener(){        //为重置按钮添加监听事件

        //同时清空name、password的数据

        public void actionPerformed(ActionEvent arg0) {

            // TODO 自动生成方法存根

            username.setText("");

            password.setText("");

        }

    });

        

    }

    

    public void display()

     {

    JFrame f =new JFrame();

    f.setTitle("登录页面");

        //窗口退出行为

        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //设置窗口大小不可变

        f.setResizable(false);

        //设置窗口打开居中

        f.setLocationRelativeTo(null);

        //窗口大小

        f.setSize(500, 300);

       

        init();

        

        //添加组件

        Container contentPanel= new Container();//添加一个contentPanel容器

         contentPanel.setLayout(null);//设置添加的contentPanel容器为流布局管理器

         contentPanel.add(user_name);

         contentPanel.add(pass_word);

         contentPanel.add(username);

         contentPanel.add(password);

         contentPanel.add(jb);

         contentPanel.add(button);

        

            f.add(contentPanel);

             //展示窗口

            f.setVisible(true);

    }

    

 

   public  void  validate(String username,String password)

     {

        

           if(username.trim().length()==0||password.trim().length()==0){

       JOptionPane.showMessageDialog(null, "用户名,密码不允许为空");

                

        return;

         }

         

       if(dao.findUser(username, password))

        {

              

        JOptionPane.showMessageDialog(null, "登录成功！");

              

             

          }else {

              JOptionPane.showMessageDialog(null, "用户名或密码错误");

             

          }

         

       }    

    

}

MainClass.java

 

package asd;

 

public class MainClass {

     

     public static void main(String[] args)

     {

            LoginForm loginForm=new LoginForm() ;    //调用

            loginForm.display();

               

     }

 

}

 

 

建表语句

CREATE TABLE `user` (

  `username` varchar(255) DEFAULT NULL,

  `password` varchar(255) DEFAULT NULL

) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

[实验任务三]：依赖倒转原则与合成复用原则

在一画图软件中提供了多种大小不同的画笔，并且可以给画笔指定不同的颜色，某设计人员对画笔进行了如上图所示的设计。通过分析，可以发现增加画笔的种类和颜色会使得系统中类的数目急剧增加，请根据合成复用原则和依赖倒转原则对上述设计进行重构。

实验要求：

1. 提交源代码；

*****型号抽象类

public abstract class Size {public abstract void sizePen();

}

 

*****具体型号类

public class SmallPen extends Size{

//小型

public void sizePen() {

System.out.println("小型");

}

}

public class MiddlePen extends Size{

//中型

public void sizePen() {

System.out.println("中型");

}

}

public class BigPen extends Size{

//大型

public void sizePen() {

System.out.println("大型");

}

}

 

 

 

*****颜色抽象类

public abstract class Color {

public abstract void colorPen();

}

 

 

*****具体颜色类

 

public class GreenPen extends Color{

public void colorPen() {

System.out.println("绿色");

}

}public class RedPen extends Color{public void colorPen() {System.out.println("红色");}}

 

 

*****钢笔

public class Pen {

//钢笔

private Size size;

private Color color;

public Size getSize() {

 return size;

}

public void setSize(Size size) {

 this.size = size;

}

public Color getColor() {

 return color;

}

public void setColor(Color color) {

 this.color = color;

}

}

*****聚合钢笔

public class MianClass {

public static void main(String[] args) {

//颜色大小随意组合

Pen pen=new Pen();

//组合小型红色钢笔

pen.setSize(new SmallPen());

pen.setColor(new RedPen());

//组合大型绿色钢笔

pen.setSize(new BigPen());

pen.setColor(new GreenPen());

}

}

1. 画出重构后的类图。

根据Pen的大小与颜色编写两个抽象了Size和Color，底层具体类extends抽象类，高层Pen类由Size和color聚合而来