第二十四章《学生信息管理系统》第3节：项目完整代码

学生信息管理系统总共有6个类，这6个类的作用已在24.1.3小节中做过介绍，此处不再赘述，以下是这6个类的源代码，读者也能在本书提供的源代码文件夹中直接下载它们。

Student.java

public class Student {
    private String sid;//学号
    private String name;//姓名
    private String sex;//性别
    private String classId;//班级
    private String phone;//家长手机号
    private String info;//备注信息

    //构造方法
    public Student() {

    }

    public Student(String sid, String name, String sex, String classId, String phone, String info) {
        this.sid = sid;
        this.name = name;
        this.sex = sex;
        this.classId = classId;
        this.phone = phone;
        this.info = info;
    }

    //get()和set()方法
    public String getSid() {
        return sid;
    }

    public void setSid(String sid) {
        this.sid = sid;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public String getClassId() {
        return classId;
    }

    public void setClassId(String classId) {
        this.classId = classId;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    public String getInfo() {
        return info;
    }

    public void setInfo(String info) {
        this.info = info;
    }
}

DBUtil.java

import java.sql.*;

public class DBUtil {
    static String driverName = "com.mysql.cj.jdbc.Driver";//驱动类
    static String url = "jdbc:mysql://localhost:3306/student";//数据库url
    static String user = "root";//用户名
    static String password = "123456";//密码
    static Connection con = null;//连接

    //静态块-加载驱动
    static {
        try {
            Class.forName(driverName);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    //建立连接
    public static Connection getConnection() throws SQLException {
        con = DriverManager.getConnection(url, user, password);
        return con;
    }

    //释放资源
    public static void close(ResultSet rs, Statement stm, Connection con) throws SQLException {
        if (rs != null) {
            rs.close();
        }
        if (stm != null) {
            stm.close();
        }
        if (con != null) {
            con.close();
        }
    }
}

StudentDao.java

import java.sql.*;
import java.util.ArrayList;

public class StudentDao {
    // 查询，查询结果以学号正序排列
    public static ArrayList<Student> query(String colName, String keywords, int page)
            throws Exception {
        ArrayList<Student> list = new ArrayList<Student>();
        Connection con = null;
        PreparedStatement pst = null;
        ResultSet rs = null;
        try {
            con = DBUtil.getConnection();
            String sql;
            if (null == keywords || "".equals(keywords.trim())) {
                sql = "select * from student   order by sid";
            } else {
                sql = "select * from student where " + colName + " like '%"
                        + keywords + "%' order by sid";
            }
            pst = con.prepareStatement(sql, ResultSet.TYPE_SCROLL_INSENSITIVE,
                    ResultSet.CONCUR_READ_ONLY);
            rs = pst.executeQuery();
            rs.last();
            int rowCount = rs.getRow();
            if (rowCount > 0) {
                rs.absolute((page - 1) * 10 + 1);
                int i = 0;
                while (i < 10 && !rs.isAfterLast()) {
                    Student student = makeObject(rs);
                    list.add(student);
                    i++;
                    rs.next();
                }
            }
        } catch (SQLException e) {
            throw e;
        } finally {
            DBUtil.close(rs, pst, con);
        }
        return list;
    }

    // 计算满足条件的学生数量有多少
    public static int getStudentNum(String colName, String keywords)
            throws Exception {
        int num = 0;
        Connection con = null;
        PreparedStatement pst = null;
        ResultSet rs = null;
        try {
            con = DBUtil.getConnection();
            String sql;
            sql = "select count(*) from student";
            if (null != keywords && !"".equals(keywords)) {// 如果关键字不为空则再加条件
                sql = sql + " where " + colName +
                        " like '%" + keywords + "%' ";
            }
            pst = con.prepareStatement(sql);
            rs = pst.executeQuery();
            while (rs.next()) {
                num = rs.getInt(1);
            }

        } catch (SQLException e) {
            throw e;
        } finally {
            DBUtil.close(rs, pst, con);
        }
        return num;
    }

    // 按学号查询单个学生信息
    public static Student queryBySid(String sid) throws Exception {
        Student student = null;
        Connection con = null;
        PreparedStatement pst = null;
        ResultSet rs = null;
        try {
            con = DBUtil.getConnection();
            pst = con.prepareStatement("select * from student   where sid=?");
            pst.setString(1, sid);
            rs = pst.executeQuery();
            if (rs.next()) {// 如果查到数据则把数据包装成一个对象
                student = makeObject(rs);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(rs, pst, con);
        }
        return student;
    }

    // 插入学生信息
    public static boolean insert(Student student) throws Exception {
        boolean flag = true;
        Connection con = null;
        PreparedStatement pst = null;
        if (isStudentExists(student.getSid())) {
            return false;
        }
        try {
            con = DBUtil.getConnection();
            String sql = "insert into student(sid,name,class_id,sex,phone,info) " +
                    "values (?,?,?,?,?,?)";
            pst = con.prepareStatement(sql);
            pst.setString(1, student.getSid());
            pst.setString(2, student.getName());
            pst.setString(3, student.getClassId());
            pst.setString(4, student.getSex());
            pst.setString(5, student.getPhone());
            pst.setString(6, student.getInfo());
            pst.executeUpdate();
        } catch (SQLException e) {
            flag = false;
            throw e;
        } finally {
            DBUtil.close(null, pst, con);
        }
        return flag;
    }

    // 判断学号是否重复
    public static boolean isStudentExists(String sid) {
        boolean isExists = false;
        Connection con = null;
        PreparedStatement pst = null;
        ResultSet rs = null;
        try {
            con = DBUtil.getConnection();
            String sql = "select * from student where  sid=?";
            pst = con.prepareStatement(sql);
            pst.setString(1, sid);
            rs = pst.executeQuery();
            if (rs.next()) {
                isExists = true;
            } else {
                isExists = false;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                DBUtil.close(rs, pst, con);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return isExists;
    }

    // 修改学生信息(学号不能修改)
    public static boolean update(Student student) throws Exception {
        boolean isSuccess = false;
        Connection con = null;
        PreparedStatement pst = null;
        try {
            con = DBUtil.getConnection();
            String sql = "update student  set name=?,class_id=?, sex=?," +
                    "phone=?,info=? where sid=?";
            pst = con.prepareStatement(sql);
            pst.setString(1, student.getName());
            pst.setString(2, student.getClassId());
            pst.setString(3, student.getSex());
            pst.setString(4, student.getPhone());
            pst.setString(5, student.getInfo());
            pst.setString(6, student.getSid());
            pst.executeUpdate();
            isSuccess = true;
        } catch (SQLException e) {
            isSuccess = false;
            throw e;
        } finally {
            DBUtil.close(null, pst, con);
        }
        return isSuccess;
    }

    // 删除一条学生信息
    public static boolean deleteBySid(String sid) throws Exception {
        boolean flag = true;
        Connection con = null;
        PreparedStatement pst = null;
        try {
            con = DBUtil.getConnection();
            pst = con.prepareStatement("delete from student where sid=?");
            pst.setString(1, sid);
            pst.executeUpdate();
        } catch (Exception e) {
            e.printStackTrace();
            flag = false;
            throw e;
        } finally {
            DBUtil.close(null, pst, con);
        }
        return flag;
    }

    //把一条数据包装为Student对象
    private static Student makeObject(ResultSet rs) throws Exception {
        // 控制游标不出范围
        Student student = new Student();
        String sid = rs.getString("sid");
        String name = rs.getString("name");
        String classId = rs.getString("class_id");
        String sex = rs.getString("sex");
        String phone = rs.getString("phone");
        String info = rs.getString("info");
        student.setClassId(classId);
        student.setSid(sid);
        student.setName(name);
        student.setSex(sex);
        student.setPhone(phone);
        student.setInfo(info);
        return student;
    }
}

MainFrame.java

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.ArrayList;
import javax.swing.table.DefaultTableModel;

public class MainFrame extends JFrame {
    JTable table;//数据表格
    JScrollPane scrollPane;//表格所在的滚动面板
    Object[] columns;//表格列名称
    DefaultTableModel data;//表格的数据模型
    JComboBox<String> jbcKeywords;// 查询关键字组合框
    JButton btnQuery;//查询按钮
    JButton btnAdd;//新增按钮
    JButton btnDelete;//删除按钮
    JButton btnUpdate;//更新按钮
    JButton btnDetail;//信息详情按钮
    JButton btnFirst;// 首页按钮
    JButton btnPreview;// 上一页按钮
    JButton btnNext;// 下一页按钮
    JButton btnLast;// 末页按钮
    JTextField txtKeywords;// 查询关键字文本框
    JLabel lblPage;// 页码标签
    int curPage = 1, pageCount = 1;// 当前页和总页数

    public MainFrame() {
        init();
    }

    private void init() {
        Container container = this.getContentPane();
        container.setLayout(null);
        // 创建组件对象
        jbcKeywords = new JComboBox<String>();
        txtKeywords = new JTextField();
        columns = new Object[]{"学号", "姓名", "班级", "性别", "家长手机号"};
        data = new DefaultTableModel(columns, 0) {
            //设置表格单元格不可编辑
            public boolean isCellEditable(int row, int column) {
                return false;
            }
        };
        table = new JTable(data);
        scrollPane = new JScrollPane(table);
        btnQuery = new JButton("查询");
        btnAdd = new JButton("新增");
        btnDelete = new JButton("删除");
        btnUpdate = new JButton("修改");
        btnDetail = new JButton("详情");
        btnFirst = new JButton("首页");
        btnPreview = new JButton("上页");
        btnNext = new JButton("下页");
        btnLast = new JButton("末页");
        lblPage = new JLabel("", JLabel.CENTER);// 文字居中显示的标签
        // 设置各组件属性

        jbcKeywords.setSize(100, 30);
        jbcKeywords.setLocation(125, 20);
        jbcKeywords.setFont(new Font("微软雅黑", Font.PLAIN, 20));
        jbcKeywords.addItem("姓名");
        jbcKeywords.addItem("性别");
        jbcKeywords.addItem("班级");

        txtKeywords.setSize(150, 30);
        txtKeywords.setLocation(235, 20);
        txtKeywords.setFont(new Font("微软雅黑", Font.PLAIN, 20));

        btnQuery.setSize(80, 30);
        btnQuery.setLocation(395, 20);
        btnQuery.setFont(new Font("微软雅黑", Font.PLAIN, 20));

        table.setRowHeight(28);
        table.setFont(new Font("微软雅黑", Font.PLAIN, 15));
        //设置表格只能被选中一行(单选模式)
        table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        table.getTableHeader().setFont(new Font("微软雅黑", Font.PLAIN, 18));
        table.getColumnModel().getColumn(0).setPreferredWidth(100);
        table.getColumnModel().getColumn(1).setPreferredWidth(100);
        table.getColumnModel().getColumn(2).setPreferredWidth(100);
        table.getColumnModel().getColumn(3).setPreferredWidth(50);
        table.getColumnModel().getColumn(4).setPreferredWidth(150);

        scrollPane.setSize(500, 311);
        scrollPane.setLocation(50, 60);

        btnAdd.setSize(90, 30);
        btnAdd.setLocation(100, 375);
        btnAdd.setFont(new Font("微软雅黑", Font.PLAIN, 20));

        btnDelete.setSize(90, 30);
        btnDelete.setLocation(200, 375);
        btnDelete.setFont(new Font("微软雅黑", Font.PLAIN, 20));

        btnUpdate.setSize(90, 30);
        btnUpdate.setLocation(300, 375);
        btnUpdate.setFont(new Font("微软雅黑", Font.PLAIN, 20));

        btnDetail.setSize(90, 30);
        btnDetail.setLocation(400, 375);
        btnDetail.setFont(new Font("微软雅黑", Font.PLAIN, 20));

        btnFirst.setSize(90, 30);
        btnFirst.setLocation(50, 420);
        btnFirst.setFont(new Font("微软雅黑", Font.PLAIN, 20));

        btnPreview.setSize(90, 30);
        btnPreview.setLocation(150, 420);
        btnPreview.setFont(new Font("微软雅黑", Font.PLAIN, 20));

        lblPage.setSize(100, 30);
        lblPage.setLocation(250, 420);
        lblPage.setHorizontalTextPosition(JLabel.CENTER);
        lblPage.setFont(new Font("微软雅黑", Font.PLAIN, 20));

        btnNext.setSize(90, 30);
        btnNext.setLocation(360, 420);
        btnNext.setFont(new Font("微软雅黑", Font.PLAIN, 20));

        btnLast.setSize(90, 30);
        btnLast.setLocation(460, 420);
        btnLast.setFont(new Font("微软雅黑", Font.PLAIN, 20));
        // 添加监听器
        btnQuery.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                // 如果curPage等于0，在查询之前必须重新赋值为1
                if (curPage == 0) {
                    curPage = 1;
                }
                showInfo(curPage);
            }
        });
        btnAdd.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                DetailDialog dialog = new DetailDialog(DetailDialog.ADD, "");
                if (dialog.isUpdate == true) {// 如果数据有更新
                    // 查询最新数据，并去除查询条件及设置查询第1页的数据
                    curPage = 1;
                    txtKeywords.setText("");
                    showInfo(curPage);
                }
            }
        });

        btnDelete.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                int row = table.getSelectedRow();
                try {
                    if (row >= 0) {
                        int r = JOptionPane.showConfirmDialog(MainFrame.this,
                                "确定要删除该学生信息？");
                        if (r == JOptionPane.OK_OPTION) {//如果单击确定按钮
                            String sid = (String) table.getValueAt(row, 0);//获得学号
                            StudentDao.deleteBySid(sid);
                            String colName = "";
                            String keywords = txtKeywords.getText();
                            //如果有查询关键字则转换出相应列名称
                            if (keywords.trim().length() != 0) {
                                colName = getColName();
                            }
                            //计算删除一条数据后总共剩余多少条数据
                            int num = StudentDao.getStudentNum(colName, keywords);
                            if (num == 0) {//如果删掉之后再无数据
                                data.removeRow(row);//
                                curPage = 0;
                                pageCount = 0;
                                lblPage.setText(curPage + "/" + pageCount);
                            } else if (data.getRowCount() == 1) {//本页仅一条数据
                                curPage--;//当前页减1（即回到上一页）
                                showInfo(curPage);//查询上页数据
                            } else {
                                showInfo(curPage);//查询本页数据
                            }
                            JOptionPane.showMessageDialog(MainFrame.this,
                                    "删除成功！");
                        }
                    } else {
                        JOptionPane.showMessageDialog(MainFrame.this,
                                "请选择要删除的学生！");
                    }
                } catch (Exception ex) {
                    JOptionPane.showMessageDialog(MainFrame.this,
                            "因系统错误删除失败！");
                    ex.printStackTrace();
                }
            }
        });

        btnUpdate.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                int row = table.getSelectedRow();
                if (row >= 0) {
                    String sid = (String) table.getValueAt(row, 0);//获得学号
                    DetailDialog dialog = new DetailDialog(DetailDialog.UPDATE, sid);
                    if (dialog.isUpdate == true) {// 如果数据有更新
                        Student student = dialog.getStudent();//获取更新后的对象
                        //把更新后对象的各项信息刷新到表格的各单元格中
                        table.setValueAt(student.getName(), row, 1);
                        table.setValueAt(student.getClassId(), row, 2);
                        table.setValueAt(student.getSex(), row, 3);
                        table.setValueAt(student.getPhone(), row, 4);
                    }
                } else {
                    JOptionPane.showMessageDialog(MainFrame.this,
                            "请选择要修改的学生！");
                }

            }
        });

        btnDetail.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                int row = table.getSelectedRow();
                if (row >= 0) {
                    String sid = (String) table.getValueAt(row, 0);//获得学号
                    DetailDialog dialog = new DetailDialog(DetailDialog.DETAIL, sid);
                } else {
                    JOptionPane.showMessageDialog(MainFrame.this,
                            "请选择要查看的学生！");
                }
            }
        });

        btnFirst.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if (curPage == 0) {
                    JOptionPane.showMessageDialog(MainFrame.this,
                            "没有数据，不能翻页！");
                } else if (curPage == 1) {//已经在第一页的情况下
                    JOptionPane.showMessageDialog(MainFrame.this,
                            "已经是第一页！");
                } else {
                    curPage = 1;//设置当前页为第一页
                    showInfo(curPage);//查询
                }
            }
        });

        btnPreview.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if (curPage == 0) {
                    JOptionPane.showMessageDialog(MainFrame.this,
                            "没有数据，不能翻页！");
                } else if (curPage == 1) {//已经在第一页的情况下
                    JOptionPane.showMessageDialog(MainFrame.this,
                            "已经是第一页！");
                } else {
                    curPage--;//设置当前页为上一页
                    showInfo(curPage);//查询
                }
            }
        });

        btnNext.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if (curPage == 0) {
                    JOptionPane.showMessageDialog(MainFrame.this,
                            "没有数据，不能翻页！");
                } else if (curPage == pageCount) {//已经在最后一页的情况下
                    JOptionPane.showMessageDialog(MainFrame.this,
                            "已经是最后一页！");
                } else {
                    curPage++;
                    showInfo(curPage);
                }
            }
        });

        btnLast.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if (curPage == 0) {
                    JOptionPane.showMessageDialog(MainFrame.this,
                            "没有数据，不能翻页！");
                } else if (curPage == pageCount) {//已经在最后一页的情况下
                    JOptionPane.showMessageDialog(MainFrame.this,
                            "已经是最后一页！");
                } else {
                    curPage = pageCount;//设置当前页为最后一页
                    showInfo(curPage);//查询
                }
            }
        });
        container.add(jbcKeywords);
        container.add(btnQuery);
        container.add(txtKeywords);
        container.add(scrollPane);
        container.add(btnAdd);
        container.add(btnDelete);
        container.add(btnUpdate);
        container.add(btnDetail);
        container.add(btnFirst);
        container.add(btnPreview);
        container.add(lblPage);
        container.add(btnNext);
        container.add(btnLast);
        showInfo(1);// 进行默认查询
    }

    //查询第page页数据
    private void showInfo(int page) {
        String colName = "";
        String keywords = txtKeywords.getText();
        //如果有查询关键字则转换出相应列名称
        if (keywords.trim().length() != 0) {
            colName = getColName();
        }
        try {
            ArrayList<Student> list = StudentDao.query(colName, keywords, page);
            int num = StudentDao.getStudentNum(colName, keywords);
            //计算总页数
            if (num % 10 == 0) {
                pageCount = num / 10;
            } else {
                pageCount = num / 10 + 1;
            }
            // 如果总页数为0，当前页也赋值为0
            if (pageCount == 0) {
                curPage = 0;
            }
            setData(list);// 把查询到的数据装入表格
            lblPage.setText(curPage + "/" + pageCount);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    // 把数据装入表格模型
    private void setData(ArrayList<Student> list) {
        int rowCount = data.getRowCount();// 获得原模型中行的数量
        for (int i = rowCount - 1; i >= 0; i--) {
            data.removeRow(i);
        }
        for (Student student : list) {
            String sid = student.getSid();
            String name = student.getName();
            String sex = student.getSex();
            String classId = student.getClassId();
            String phone = student.getPhone();
            String info = student.getInfo();
            data.addRow(new Object[]{sid, name, classId, sex, phone});
        }
    }

    String getColName() {
        String colName = "";
        String selectedItem = jbcKeywords.getSelectedItem().toString();
        switch (selectedItem) {
            case "姓名":
                colName = "name";
                break;
            case "性别":
                colName = "sex";
                break;
            case "班级":
                colName = "class_id";
                break;
        }
        return colName;
    }
}

DetailDialog.java

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class DetailDialog extends JDialog {
    //界面所显示的对象
    Student student = new Student();
    //定义打开模式
    public static final int ADD = 1;//新增模式
    public static final int UPDATE = 2;//修改模式
    public static final int DETAIL = 3;//详情模式
    //当前窗体对象的模式
    private int mode;
    //关闭窗口时是否单击了取消按钮
    boolean isUpdate = false;//是否更新了数据库
    //定义组件
    JLabel lblSid;//学号标签
    JTextField txtSid;//学号文本框
    JLabel lblName;//姓名标签
    JTextField txtName;//姓名文本框
    JLabel lblSex;//性别标签
    JRadioButton rbtMale;//单选按钮男
    JRadioButton rbtFemale;//单选按钮女
    ButtonGroup group;//按钮组
    JLabel lblClassId;//班级标签
    JTextField txtClassId;//班级文本框
    JLabel lblPhone;//家长手机标签
    JTextField txtPhone;//家长手机文本框
    JLabel lblInfo;//备注信息标签
    JTextArea txaInfo;//备注信息文本区
    JScrollPane scrollPane;//备注文本区的滚动面板
    JButton btnOK;//确定按钮
    JButton btnCancel;//取消按钮

    public DetailDialog(int mode, String sid) {
        init(mode, sid);
    }

    private void init(int mode, String sid) {
        this.mode = mode;
        String title = "";
        switch (mode) {
            case ADD:
                title = "新增学生信息";
                break;
            case UPDATE:
                title = "修改学生信息";
                break;
            case DETAIL:
                title = "学生信息详情";
                break;
        }
        Container container = this.getContentPane();
        container.setLayout(null);

        lblSid = new JLabel("学号");
        txtSid = new JTextField();
        lblName = new JLabel("姓名");
        txtName = new JTextField();
        lblSex = new JLabel("性别");
        rbtMale = new JRadioButton("男");
        rbtFemale = new JRadioButton("女");
        group = new ButtonGroup();
        group.add(rbtMale);
        group.add(rbtFemale);
        lblClassId = new JLabel("班级");
        txtClassId = new JTextField();
        lblPhone = new JLabel("手机");
        txtPhone = new JTextField();
        lblInfo = new JLabel("备注信息(不超过50字)");
        txaInfo = new JTextArea();
        scrollPane = new JScrollPane(txaInfo);
        btnOK = new JButton("确定");
        btnCancel = new JButton("取消");
        //设置组件属性
        lblSid.setSize(50, 25);
        lblSid.setLocation(50, 20);
        lblSid.setFont(new Font("微软雅黑", Font.PLAIN, 18));

        txtSid.setSize(250, 25);
        txtSid.setLocation(100, 20);
        txtSid.setFont(new Font("微软雅黑", Font.PLAIN, 15));

        lblName.setSize(50, 25);
        lblName.setLocation(50, 50);
        lblName.setFont(new Font("微软雅黑", Font.PLAIN, 18));

        txtName.setSize(250, 25);
        txtName.setLocation(100, 50);
        txtName.setFont(new Font("微软雅黑", Font.PLAIN, 15));

        lblSex.setSize(50, 25);
        lblSex.setLocation(50, 80);
        lblSex.setFont(new Font("微软雅黑", Font.PLAIN, 18));

        rbtMale.setSize(50, 25);
        rbtMale.setLocation(100, 80);
        rbtMale.setFont(new Font("微软雅黑", Font.PLAIN, 18));

        rbtFemale.setSize(50, 25);
        rbtFemale.setLocation(150, 80);
        rbtFemale.setFont(new Font("微软雅黑", Font.PLAIN, 18));

        lblClassId.setSize(50, 25);
        lblClassId.setLocation(50, 110);
        lblClassId.setFont(new Font("微软雅黑", Font.PLAIN, 18));

        txtClassId.setSize(250, 25);
        txtClassId.setLocation(100, 110);
        txtClassId.setFont(new Font("微软雅黑", Font.PLAIN, 15));

        lblPhone.setSize(50, 25);
        lblPhone.setLocation(50, 140);
        lblPhone.setFont(new Font("微软雅黑", Font.PLAIN, 18));

        txtPhone.setSize(250, 25);
        txtPhone.setLocation(100, 140);
        txtPhone.setFont(new Font("微软雅黑", Font.PLAIN, 15));

        lblInfo.setSize(250, 25);
        lblInfo.setLocation(50, 170);
        lblInfo.setFont(new Font("微软雅黑", Font.PLAIN, 18));

        txaInfo.setFont(new Font("微软雅黑", Font.PLAIN, 15));
        scrollPane.setSize(300, 100);
        scrollPane.setLocation(50, 200);
        scrollPane.setFont(new Font("微软雅黑", Font.PLAIN, 18));

        if (mode != ADD) {//如果不是新增模式，则把信息详情反写入相应文本框
            try {
                student = StudentDao.queryBySid(sid);
                this.txtSid.setText(student.getSid());//反写学号
                this.txtSid.setEditable(false);//学号只读
                this.txtName.setText(student.getName());//反写姓名
                this.txtClassId.setText(student.getClassId());//反写班级
                this.txtPhone.setText(student.getPhone());//反写手机号
                this.txaInfo.setText(student.getInfo());//反写备注
                if ("男".equals(student.getSex())) {//反选性别
                    this.rbtMale.setSelected(true);
                } else {
                    this.rbtFemale.setSelected(true);
                }
            } catch (Exception e) {
                JOptionPane.showMessageDialog(DetailDialog.this,
                        "因系统错误获取信息失败！");
                e.printStackTrace();
            }
        }
        //如果是详情模式则设置组件为不可编辑状态
        if (mode == DETAIL) {
            this.txtName.setEditable(false);
            this.txtClassId.setEditable(false);
            this.txtPhone.setEditable(false);
            this.txaInfo.setEnabled(false);
            this.rbtMale.setEnabled(false);
            this.rbtFemale.setEnabled(false);
        }

        btnOK.setSize(80, 25);
        btnOK.setLocation(100, 315);
        btnOK.setFont(new Font("微软雅黑", Font.PLAIN, 18));
        btnOK.addActionListener(new ActionListener() {
            //新增或修改成功
            public void operateSuccess(String message) {
                JOptionPane.showMessageDialog(DetailDialog.this, message);
                isUpdate = true;//表示数据有更新
                DetailDialog.this.dispose();
            }

            @Override
            public void actionPerformed(ActionEvent e) {
                Student student = checkData();
                if (mode == ADD) {//如果是新增
                    if (student != null) {
                        try {
                            StudentDao.insert(student);
                            operateSuccess("新增成功！");
                        } catch (Exception ex) {
                            ex.printStackTrace();
                            JOptionPane.showMessageDialog(DetailDialog.this,
                                    "因系统错误新增信息失败！");
                        }
                    }
                } else if (mode == UPDATE) {//修改模式
                    try {
                        if (student != null) {
                            int r = JOptionPane.showConfirmDialog(DetailDialog.this,
                                    "确定要修改该学生信息？");
                            if (r == JOptionPane.OK_OPTION) {
                                StudentDao.update(student);
                                DetailDialog.this.student = student;//更新对象
                                operateSuccess("修改成功！");
                            }
                        }
                    } catch (Exception ex) {
                        ex.printStackTrace();
                        JOptionPane.showMessageDialog(DetailDialog.this,
                                "因系统错误修改信息失败！");
                    }
                } else if (mode == UPDATE) {
                    DetailDialog.this.dispose();
                }

            }
        });

        btnCancel.setSize(80, 25);
        btnCancel.setLocation(220, 315);
        btnCancel.setFont(new Font("微软雅黑", Font.PLAIN, 18));
        btnCancel.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                DetailDialog.this.dispose();
            }
        });

        container.add(lblSid);
        container.add(txtSid);
        container.add(lblName);
        container.add(txtName);
        container.add(lblSex);
        container.add(rbtMale);
        container.add(rbtFemale);
        container.add(lblClassId);
        container.add(txtClassId);
        container.add(lblPhone);
        container.add(txtPhone);
        container.add(lblInfo);
        container.add(scrollPane);
        container.add(btnOK);
        container.add(btnCancel);
        //显示窗体
        this.setTitle(title);
        this.setModal(true);
        this.setSize(400, 400);
        this.setLocationRelativeTo(null);
        this.setVisible(true);
    }

    /*检查数据的合理性
    如果数据合理则返回组装好的Student对象，否则返回null
     */
    private Student checkData() {
        String sid = txtSid.getText();
        String name = txtName.getText();
        String sex = "";
        String classId = txtClassId.getText();
        String phone = txtPhone.getText();
        String info = txaInfo.getText();
        if (sid.length() == 0) {//如果学号为空
            JOptionPane.showMessageDialog(DetailDialog.this,
                    "学号不能为空！");
            return null;
        }
        if (sid.length() >= 10) {//如果学号长度超过10
            JOptionPane.showMessageDialog(DetailDialog.this,
                    "学号长度不能超过10！");
            return null;
        }
        if (mode == ADD) {//如果是新增学生信息，则检查学号重复性
            if (StudentDao.isStudentExists(sid.trim())) {
                JOptionPane.showMessageDialog(DetailDialog.this,
                        "学号出现重复，不能新增！");
                return null;
            }
        }
        if (name.length() == 0) {//如果姓名为空
            JOptionPane.showMessageDialog(DetailDialog.this,
                    "姓名不能为空！");
            return null;
        }
        if (name.length() >= 10) {//如果姓名长度超过10
            JOptionPane.showMessageDialog(DetailDialog.this,
                    "姓名长度不能超过10！");
            return null;
        }
        //如果没有选择性别
        if (rbtMale.isSelected() == false && rbtFemale.isSelected() == false) {
            JOptionPane.showMessageDialog(DetailDialog.this,
                    "请选择性别！");
            return null;
        } else {//选择了性别的情况下把所选性别赋值给sex
            if (rbtMale.isSelected()) {
                sex = rbtMale.getText();
            } else {
                sex = rbtFemale.getText();
            }
        }
        if (classId.length() == 0) {//如果班级为空
            JOptionPane.showMessageDialog(DetailDialog.this,
                    "班级不能为空！");
            return null;
        }
        if (classId.length() >= 10) {//如果班级长度超过10
            JOptionPane.showMessageDialog(DetailDialog.this,
                    "班级长度不能超过10！");
            return null;
        }

        if (phone.length() != 11) {//如果手机号不是11位
            JOptionPane.showMessageDialog(DetailDialog.this,
                    "手机号必须是11位！");
            return null;
        }
        if (info.length() >= 50) {//如果备注信息长度超过50
            JOptionPane.showMessageDialog(DetailDialog.this,
                    "备注信息不能超过50个字！");
            return null;
        }
        Student student = new Student();
        //把用户填写的数据组装到Student对象中
        student.setSid(sid);
        student.setName(name);
        student.setSex(sex);
        student.setClassId(classId);
        student.setPhone(phone);
        student.setInfo(info);
        return student;
    }

    public Student getStudent() {
        return this.student;
    }
}

Main.java

import javax.swing.JFrame;

public class Main {
    public static void main(String[] args) {
        MainFrame frame = new MainFrame();
        frame.setSize(600, 500);
        frame.setLocationRelativeTo(null);
        frame.setTitle("学生信息管理系统");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}

文字版教程还配有更详细的视频讲解，小伙伴们可以​​点击这里​​观看。