实验1：UML与面向对象程序设计原则

本次实验属于模仿型实验，通过本次实验学生将掌握以下内容：

1、掌握面向对象程序设计中类与类之间的关系以及对应的UML类图；

2、理解面向对象程序设计原则。

 

[实验任务一]：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。

4种：泛化，关联，依赖，实现

[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）；

2.注意编程规范。

DBUtil

package org.example;

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/first?serverTimezone=GMT%2B8&useSSL=false";

public static String db_user = "root";

public static String db_pass = "wwsa20030207";

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");

}

}

}

LoginForm

package org.example;

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

package org.example;

public class MainClass {

public static void main(String[] args)

{

LoginForm loginForm=new LoginForm() ;    //调用

        loginForm.display();

}

}

UserDao

package org.example;

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;

}

}

Sql文件

/*

Navicat Premium Data Transfer

Source Server         : localhost

Source Server Type    : MySQL

Source Server Version : 80031 (8.0.31)

Source Host           : localhost:3306

Source Schema         : first

Target Server Type    : MySQL

Target Server Version : 80031 (8.0.31)

File Encoding         : 65001

Date: 23/10/2023 09:14:58

*/

SET NAMES utf8mb4;

SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------

-- Table structure for user

-- ----------------------------

DROP TABLE IF EXISTS `user`;

CREATE TABLE `user`  (

`username` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL,

`password` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL

) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci ROW_FORMAT = Dynamic;

-- ----------------------------

-- Records of user

-- ----------------------------

INSERT INTO `user` VALUES ('123zhang', '123456');

SET FOREIGN_KEY_CHECKS = 1;

 

[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；

BigPen

package org.example.test2;

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());

}

}

Color

package org.example.test2;

public abstract class Color {

public abstract void colorPen();

}

GreenPen

package org.example.test2;

public class GreenPen extends Color{

public void colorPen() {

System.out.println("绿色");

}

}

MainClass

package org.example.test2;

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());

}

}

MiddlePen

package org.example.test2;

public class MiddlePen extends Size {

//中型

    public void sizePen() {

System.out.println("中型");

}

}

Pen

package org.example.test2;

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;

}

}

RedPen

package org.example.test2;

public class RedPen extends Color {

public void colorPen() {

System.out.println("红色");

}

}

Size

package org.example.test2;

public abstract class Size {

public abstract void sizePen();

}

SmallPen

package org.example.test2;

public class SmallPen extends Size {

//小型

    public void sizePen() {

System.out.println("小型");

}

}

2. 画出重构后的类图。