JDBC实验

Posted 2020-08-21

实验要求

创建一个学生数据库，平台是mysql，图形界面用Swing编写，实现学生的增删改查功能。最终结果如下图所示

这次实验本来是学习JDBC使用的，但难点不在数据库，在图形界面上~~~

 

整体思路：

1.创建一个student数据库，写一个Student类。

2.先用java实现数据库的增删改查操作，因此创建一个DBControl类与数据库进行交互。

3.画出整个图形界面，因为表格是放在ScrollPane中的，所以在表格处画出一个ScrollPane即可，表格由代码另外创建。整个界面就是一个MyWindow类。

4.由于表格的数据是放在tableModel中的，所以创建一个MyTabelModel类，这个类通过调用DBcontrol类的方法来实现数据的存取。

 

难点的解决

每次对学生进行增删改查后，表要实时变化。

我在界面的代码中写了一个refresh函数，每当有有数据变化，它都会将当前表所在的JScrollPane移除，

之后TableModel再从数据库中读取数据，重新建立一个表格，再将其添加到新建的JScrollPane中，放到界面中去。

 

这是所有的代码

student类

package model;

public class Student {
    private String stu_id;
    private String stu_name;
    private String birthday;
    private String sex;
    private String province;
    private String city;
    public Student()
    {}
    public Student(String stu_id, String stu_name, String birthday, String sex, String province, String city) {
        super();
        this.stu_id = stu_id;
        this.stu_name = stu_name;
        this.birthday = birthday;
        this.sex = sex;
        this.province = province;
        this.city = city;
    }
    /**
     * @return the stu_id
     */
    public String getStu_id() {
        return stu_id;
    }
    /**
     * @param stu_id the stu_id to set
     */
    public void setStu_id(String stu_id) {
        this.stu_id = stu_id;
    }
    /**
     * @return the stu_name
     */
    public String getStu_name() {
        return stu_name;
    }
    /**
     * @param stu_name the stu_name to set
     */
    public void setStu_name(String stu_name) {
        this.stu_name = stu_name;
    }
    /**
     * @return the birthday
     */
    public String getBirthday() {
        return birthday;
    }
    /**
     * @param birthday the birthday to set
     */
    public void setBirthday(String birthday) {
        this.birthday = birthday;
    }
    /**
     * @return the sex
     */
    public String getSex() {
        return sex;
    }
    /**
     * @param sex the sex to set
     */
    public void setSex(String sex) {
        this.sex = sex;
    }
    /**
     * @return the province
     */
    public String getProvince() {
        return province;
    }
    /**
     * @param province the province to set
     */
    public void setProvince(String province) {
        this.province = province;
    }
    /**
     * @return the city
     */
    public String getCity() {
        return city;
    }
    /**
     * @param city the city to set
     */
    public void setCity(String city) {
        this.city = city;
    }
}

View Code

 

DBControl类

package dao;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import model.Student;

public class DBControl {
    public static final String URL = "jdbc:mysql://localhost:3306/student";
    public static final String USER = "root";
    public static final String PASSWORD = "123456";
    private static Connection conn = null;
    static {
        try {
            // 1.加载驱动程序
            Class.forName("com.mysql.jdbc.Driver");
            // 2. 获得数据库连接
            conn = DriverManager.getConnection(URL, USER, PASSWORD);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public static Connection getConnection() {
        return conn;
    }

    // 获得一个日期的毫秒数
    public static long getMs(String str) {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        // 此处会抛异常
        try {
            Date date = sdf.parse(str);
            return date.getTime();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return 0;
    }

    // 返回学生人数
    public int getSize() throws SQLException {
        Connection conn = getConnection();
        Statement stmt = conn.createStatement();
        ResultSet rs = stmt.executeQuery("SELECT stu_id FROM stu_info where del = 0");
        int size = 0;
        while(rs.next())
        {
            size++;
        }
        rs.close(); 
        stmt.close();
        return size;
    }

    // 返回全部学生的数据
    public List<Student> getAll() throws SQLException {
        Connection conn = getConnection();
        Statement stmt = conn.createStatement();
        ResultSet rs = stmt
                .executeQuery("SELECT stu_id, stu_name, birthday, sex, province, city FROM stu_info where del = 0");

        List<Student> sl = new ArrayList<Student>();
        Student s = null;
        while (rs.next()) {
            s = new Student();
            s.setStu_id(rs.getString("stu_id"));
            s.setStu_name(rs.getString("stu_name"));
            s.setBirthday(rs.getDate("birthday").toString());
            s.setSex(rs.getString("sex"));
            s.setProvince(rs.getString("province"));
            s.setCity(rs.getString("city"));
            sl.add(s);
        }
        rs.close();
        stmt.close();
        return sl;
    }

    // 增加学生记录
    public boolean add(Student s) throws SQLException {
        // 获取连接
        Connection conn = getConnection();
        // sql
        String sql = "INSERT INTO stu_info(stu_id, stu_name, birthday, sex, province, city, del)"
                + "VALUES(?,?,?,?,?,?,0);";
        // 预编译
        PreparedStatement ptmt = conn.prepareStatement(sql); // 预编译SQL，减少sql执行

        // 传参
        ptmt.setString(1, s.getStu_id());
        ptmt.setString(2, s.getStu_name());
        long date = getMs(s.getBirthday());
        ptmt.setDate(3, new java.sql.Date(date));
        ptmt.setString(4, s.getSex());
        ptmt.setString(5, s.getProvince());
        ptmt.setString(6, s.getCity());

        // 执行
        try {
            ptmt.execute();
        } catch (Exception e) {
            e.printStackTrace();
            ptmt.close();
            return false;
        }
        ptmt.close();
        return true;
    }

    // 根据学号查询学生
    public Student get(String stu_id) throws SQLException {
        // 获取连接
        Connection conn = getConnection();
        // sql, 每行加空格
        String sql = "select * from stu_info where stu_id=? and del = 0";

        // 预编译SQL，减少sql执行
        PreparedStatement ptmt = conn.prepareStatement(sql);
        // 传参
        ptmt.setString(1, stu_id);
        // 执行
        ResultSet rs = ptmt.executeQuery();
        Student s = null;
        while (rs.next()) {
            s = new Student();
            s.setStu_id(rs.getString("stu_id"));
            s.setStu_name(rs.getString("stu_name"));
            s.setBirthday(rs.getDate("birthday").toString());
            s.setSex(rs.getString("sex"));
            s.setProvince(rs.getString("province"));
            s.setCity(rs.getString("city"));
        }
        rs.close();
        ptmt.close();
        return s;
    }

    // 根据学号删除学生
    public boolean del(String stu_id) throws SQLException {
        // 获取连接
        Connection conn = getConnection();
        // sql, 每行加空格
        String sql = "UPDATE stu_info SET del=1, stu_id = \\‘"+stu_id+"  \\‘ WHERE stu_id = ?";

        // 预编译SQL，减少sql执行
        PreparedStatement ptmt = conn.prepareStatement(sql);
        // 传参
        ptmt.setString(1, stu_id);
        // 执行
        try {
            ptmt.execute();
            ptmt.close();
            return true;
        } catch (Exception e) {
            ptmt.close();
            e.printStackTrace();
            return false;
        }
    }

    // 根据学号改变学生的信息
    public boolean change(String stu_id, Student s) throws SQLException {
        // 获取连接
        Connection conn = getConnection();
        // sql, 每行加空格
        String sql = "UPDATE stu_info SET stu_name=?, birthday=?, sex=?, province=?, city = ?" + "WHERE stu_id = \\‘"
                + stu_id + "\\‘ and del = 0";
        // 预编译
        PreparedStatement ptmt = conn.prepareStatement(sql);

        // 传参
        ptmt.setString(1, s.getStu_name());
        long date = getMs(s.getBirthday());
        ptmt.setDate(2, new java.sql.Date(date));
        ptmt.setString(3, s.getSex());
        ptmt.setString(4, s.getProvince());
        ptmt.setString(5, s.getCity());
        //执行
        try {
            ptmt.execute();
            ptmt.close();
            return true;
        } catch (Exception e) {
            ptmt.close();
            e.printStackTrace();
            return false;
        }
    }
}

View Code

 

MyTableModel类

package ui;

import java.util.List;

import javax.swing.table.AbstractTableModel;

import dao.DBControl;
import model.Student;

public class MyTableModel extends AbstractTableModel  {
    private static final long serialVersionUID = 1L;
    
    DBControl dbc = new DBControl();
    private String[] columnNames = {"stu_id","stu_name","birthday","sex","province","city"};
    private List<Student> studentList;
    private String[][] studentInfo;
    
    //列数
    private int column;
    //行数
    private int row;

    //一个row行column列的表格模型
    public MyTableModel() throws Exception
    {
        this.row = dbc.getSize();
        this.column = 6;
        this.studentList = dbc.getAll();
        studentInfo = new String[row][6];
        int i = 0;
        for (Student st : studentList)
        {
            studentInfo[i][0] = st.getStu_id();
            studentInfo[i][1] = st.getStu_name();
            studentInfo[i][2] = st.getBirthday();
            studentInfo[i][3] = st.getSex();
            studentInfo[i][4] = st.getProvince();
            studentInfo[i][5] = st.getCity();
            i++;
        }
    }
    //获得行数，即显示的表格数据有多少行
    public int getRowCount() {
        return row;
    }
    //获得列数，即显示的表格数据有多少列
    public int getColumnCount() {
        return column;
    }
    //获得某一行某一列的值，即为所有格子添加数据
    public Object getValueAt(int r, int c) {
        return studentInfo[r][c];
    }
    //获得某一列的列名，即显示所有列名
    public String getColumnName(int c) {
        return    columnNames[c];
    }
    //通过学号获得某个学生信息所在的行数
    public int getRow(String stu_id)
    {
        int result = -1;
        int i = studentInfo.length;
        for (int j = 0; j < i; j++)
        {
            if (studentInfo[j][0].equals(stu_id))
            {
                result = j;
                break;
            }
        }
        return result;
    }
}

View Code

 

MyWindow类

package ui;

import java.awt.EventQueue;

public class MyWindow {
    DBControl dbc = new DBControl();
    MyTableModel mtm;
    private JFrame frame;
    private JTextField numberText;
    private JTextField nameText;
    private JTextField birthdayText;
    private JTextField provinceText;
    private JTextField cityText;
    private JTextField queryNumberText;
    private JRadioButton maleButton;
    private JRadioButton femaleButton;
    private JButton addButton;
    private JButton deleteButton;
    private JButton refreshButton;
    private JScrollPane scrollPane;
    private JButton queryButton;
    private JTable table;
    private JLabel label_1;
    private JLabel label_2;
    private JLabel label_3;
    private JLabel label_4;
    private JLabel label_5;

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    MyWindow window = new MyWindow();
                    window.frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the application.
     */
    public MyWindow() throws Exception {
        initialize();
    }

    // 创建一个表格
    public void refreshTable() throws Exception {
        if (scrollPane != null) {
            frame.remove(scrollPane);
        }
        // 创建一个model
        MyTableModel model = new MyTableModel();
        // 通过model建立一个表
        table = new JTable(model);
        // 将表放到滚动面板里
        scrollPane = new JScrollPane(table);
        scrollPane.setBounds(224, 34, 465, 426);
        frame.getContentPane().add(scrollPane);
        table.addMouseListener(new tableListener());
    }

    // 为左侧表格赋值
    private void setLeftPanel(String stu_id, String name, String birthday, String sex, String province, String city) {
        numberText.setText(stu_id);
        nameText.setText(name);
        birthdayText.setText(birthday);
        maleButton.setSelected(false);
        femaleButton.setSelected(false);
        if (sex.equals("男"))
            maleButton.setSelected(true);
        else
            femaleButton.setSelected(true);
        provinceText.setText(province);
        cityText.setText(city);
    }

    // 取得左侧表格值
    private Student getLeftPanel() {
        Student st = new Student();
        st.setStu_id(numberText.getText());
        st.setStu_name(nameText.getText());
        st.setBirthday(birthdayText.getText());
        st.setSex(maleButton.isSelected() ? "男" : "女");
        st.setProvince(provinceText.getText());
        st.setCity(cityText.getText());
        return st;
    }

    private void initialize() throws Exception {
        frame = new JFrame();
        frame.setBounds(100, 100, 756, 559);

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);

        JLabel lblNewLabel = new JLabel("学生");
        lblNewLabel.setBounds(59, 10, 54, 27);
        frame.getContentPane().add(lblNewLabel);

        numberText = new JTextField();
        numberText.setBounds(59, 47, 102, 40);
        frame.getContentPane().add(numberText);
        numberText.setColumns(10);

        nameText = new JTextField();
        nameText.setColumns(10);
        nameText.setBounds(59, 97, 102, 40);
        frame.getContentPane().add(nameText);

        birthdayText = new JTextField();
        birthdayText.setColumns(10);
        birthdayText.setBounds(59, 147, 102, 40);
        frame.getContentPane().add(birthdayText);

        maleButton = new JRadioButton("男");
        maleButton.setBounds(55, 219, 53, 23);
        frame.getContentPane().add(maleButton);

        femaleButton = new JRadioButton("女");
        femaleButton.setBounds(110, 219, 51, 23);
        frame.getContentPane().add(femaleButton);

        provinceText = new JTextField();
        provinceText.setColumns(10);
        provinceText.setBounds(59, 266, 102, 40);
        frame.getContentPane().add(provinceText);

        cityText = new JTextField();
        cityText.setColumns(10);
        cityText.setBounds(59, 316, 102, 40);
        frame.getContentPane().add(cityText);

        addButton = new JButton("添加");
        addButton.setBounds(69, 366, 93, 27);
        frame.getContentPane().add(addButton);

        deleteButton = new JButton("删除");
        deleteButton.setBounds(68, 403, 93, 27);
        frame.getContentPane().add(deleteButton);

        refreshButton = new JButton("更新");
        refreshButton.setBounds(68, 440, 93, 27);
        frame.getContentPane().add(refreshButton);

        refreshTable();

        queryButton = new JButton("查询");
        queryButton.setBounds(456, 470, 93, 27);
        frame.getContentPane().add(queryButton);

        queryNumberText = new JTextField();
        queryNumberText.setColumns(10);
        queryNumberText.setBounds(344, 470, 102, 27);
        frame.getContentPane().add(queryNumberText);

        JLabel label = new JLabel("学号");
        label.setBounds(280, 470, 54, 27);
        frame.getContentPane().add(label);
        
        label_1 = new JLabel("学号");
        label_1.setBounds(14, 53, 35, 27);
        frame.getContentPane().add(label_1);
        
        label_2 = new JLabel("名字");
        label_2.setBounds(14, 97, 35, 27);
        frame.getContentPane().add(label_2);
        
        label_3 = new JLabel("生日");
        label_3.setBounds(14, 147, 35, 27);
        frame.getContentPane().add(label_3);
        
        label_4 = new JLabel("省份");
        label_4.setBounds(10, 271, 39, 28);
        frame.getContentPane().add(label_4);
        
        label_5 = new JLabel("城市");
        label_5.setBounds(10, 328, 35, 23);
        frame.getContentPane().add(label_5);
        queryButton.addActionListener(new queryButtonListener());
        addButton.addActionListener(new addButtonListener());
        deleteButton.addActionListener(new deleteButtonListener());
        refreshButton.addActionListener(new refreshButtonListener());
        maleButton.addActionListener(new maleButtonListener());
        femaleButton.addActionListener(new femaleButtonListener());
        
    }

    // 查询一个学生
    private class queryButtonListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            if (!queryNumberText.getText().equals("")) {
                try {
                    Student st = dbc.get(queryNumberText.getText());
                    if (st != null) {
                        setLeftPanel(st.getStu_id(), st.getStu_name(), st.getBirthday(), st.getSex(), st.getProvince(),
                                st.getCity());
                        int row = new MyTableModel().getRow(st.getStu_id());
                        if (row != -1)
                        {
                            table.changeSelection(row, row, false, false);
                        }
                    } else {
                        JOptionPane.showMessageDialog(null, "查无此人");
                    }
                } catch (Exception ex) {
                    ex.printStackTrace();
                }
            } else {
                JOptionPane.showMessageDialog(null, "请输入学号");
            }
        }
    }

    // 添加一个学生
    private class addButtonListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            Student st = getLeftPanel();
            //如果有空项
            if (st.getStu_id().equals("") || st.getStu_name().equals("") || st.getProvince().equals("") || st.getCity().equals(""))
            {
                JOptionPane.showMessageDialog(null, "有些信息没有填");
                return;
            }
            //如果日期格式不对
            if (!dateFormatIsCorrect(st.getBirthday()))
            {
                JOptionPane.showMessageDialog(null, "生日格式错误，应为yyyy-mm-dd");
                return;
            }
            //如果学号和别人重复
            try {
                if (new MyTableModel().getRow(st.getStu_id())!=-1)
                {
                    JOptionPane.showMessageDialog(null, "学号重复了");
                    return;
                }
            } catch (Exception ex)
            {
                ex.printStackTrace();
            }
            //如果没有选择性别
            if (!maleButton.isSelected()&&!femaleButton.isSelected())
            {
                JOptionPane.showMessageDialog(null, "请选择你的性别");
                return;
            }
            
            if (!st.getStu_id().equals("")) {
                try {
                    dbc.add(st);
                    
                    //更新列表
                    refreshTable();
                    //选中当前这个新添加的人
                    int row = new MyTableModel().getRow(st.getStu_id());
                    if (row != -1)
                    {
                        table.changeSelection(row, row, false, false);
                    }
                    JOptionPane.showMessageDialog(null, "添加成功");
                } catch (Exception ex) {
                    ex.printStackTrace();
                }
            } else {
                JOptionPane.showMessageDialog(null, "请输入学号！");
            }
        }
    }

    // 删除一个学生
    private class deleteButtonListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            String stu_id = numberText.getText();
            //System.out.println(stu_id);
            //如果没有这个学号
            try {
                int row = new MyTableModel().getRow(stu_id);
                if (row == -1)
                {
                    JOptionPane.showMessageDialog(null, "没有这个学号");
                    return;
                }
            } catch (Exception ex)
            {
                //ex.printStackTrace();
                return;
            }
            
            if (!stu_id.equals("")) {
                try {
                    if (dbc.del(stu_id))
                    {
                        JOptionPane.showMessageDialog(null, "删除成功");
                        refreshTable();
                    }
                    else
                    {
                        JOptionPane.showMessageDialog(null, "删除失败");
                    }
                } catch (Exception ex) {
                    ex.printStackTrace();
                }
            } else {
                JOptionPane.showMessageDialog(null, "请输入学号！");
            }
        }
    }
    
    //更新一个学生的信息
    private class refreshButtonListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            Student st = getLeftPanel();
            if (!st.getStu_id().equals(""))
            {
                try {
                    if (dbc.change(st.getStu_id(), st))
                    {
                        JOptionPane.showMessageDialog(null, "更新成功");
                        refreshTable();
                        //这个学生变成选中状态
                        int row = new MyTableModel().getRow(st.getStu_id());
                        if (row != -1)
                        {
                            table.changeSelection(row, row, false, false);
                        }
                    }
                    else
                    {
                        JOptionPane.showMessageDialog(null, "更新失败");
                    }
                } catch (Exception ex)
                {
                    ex.printStackTrace();
                }
            }
            else
            {
                JOptionPane.showMessageDialog(null, "请输入学号！");
            }
        }
    }
    
    //选中男性按钮
    private class maleButtonListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            femaleButton.setSelected(false);
        }
    }
    
    //选中女性按钮
    private class femaleButtonListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            maleButton.setSelected(false);
        }
    }
    
    //表格事件
    private class tableListener implements MouseListener {
        @Override
        public void mouseClicked(MouseEvent e) {
            try
            {
                mtm = new MyTableModel();
            } catch (Exception ex)
            {
                ex.printStackTrace();
            }
            int row = table.getSelectedRow();
            setLeftPanel((String)mtm.getValueAt(row, 0), (String)mtm.getValueAt(row, 1), (String)mtm.getValueAt(row, 2),
                    (String)mtm.getValueAt(row, 3), (String)mtm.getValueAt(row, 4), (String)mtm.getValueAt(row, 5));
        }
        public void mousePressed(MouseEvent e) {}
        public void mouseReleased(MouseEvent e) {}
        public void mouseEntered(MouseEvent e) {}
        public void mouseExited(MouseEvent e) {}
    }
    //确保输入日期格式正确
    private boolean dateFormatIsCorrect(String birthday)
    {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        // 此处会抛异常
        try {
            Date date = sdf.parse(birthday);
            return true;
        } catch (Exception e) {
            return false;
        }
    }
}

View Code

最后的效果（由于每次操作表格都会直接更新，所以全部检索按钮就不需要了）