1. 数据回显
其实数据回显就是为修改功能的实现做准备的
1.1 在MainView类中，创建一个方法获取选中行的id
// 获取选中的行的idpublic int[] getSelectedRowIds() {int[] selectedRows = mainViewTable.getSelectedRows();int[] ids = new int[selectedRows.length]; // 用来存储idfor (int i = 0; i < selectedRows.length; i++) {int selectedRowIndex = selectedRows[i];Object idObj = mainViewTable.getValueAt(selectedRowIndex, 0);ids[i]= Integer.parseInt(idObj.toString()); // toString()是将转为字符串的类型}return ids;}1.2 给按钮添加点击事件
1.3 在MainViewHandler进行相应的处理
if ("修改".equals(text)){int[] selectedRowIds = mainView.getSelectedRowIds();if (selectedRowIds.length != 1) {JOptionPane.showMessageDialog(mainView, "请选择一条记录！");return;}new UpdateStudentView(mainView, selectedRowIds[0]);}
1.4 编写UpdateStudentView界面代码
与上一篇博客中的添加数据界面相同，直接给出代码了
package com.student_view;import com.entity.Student;
import com.handler.UpdateStudentViewHandler;
import com.service.Impl.StudentServiceImpl;import javax.swing.*;
import java.awt.*;/*** @Author：xiexu* @Date：2023/12/16 21:52*/
public class UpdateStudentView extends JDialog {// 声明一系列组件JPanel jPanel = new JPanel(new FlowLayout(FlowLayout.CENTER, 10, 20));JLabel idLabel = new JLabel("学号", JLabel.RIGHT);JTextField idTextField = new JTextField();JLabel nameLabel = new JLabel("姓名", JLabel.RIGHT); // 第二个参数表示水平的排列方式JTextField nameTextField = new JTextField();JLabel noLabel = new JLabel("学号", JLabel.RIGHT);JTextField noTextField = new JTextField();JLabel homeLabel = new JLabel("家乡", JLabel.RIGHT);JTextField homeTextField = new JTextField();JLabel chineseLabel = new JLabel("语文成绩", JLabel.RIGHT);JTextField chineseTextField = new JTextField();JLabel mathLabel = new JLabel("数学成绩", JLabel.RIGHT);JTextField mathTextField = new JTextField();JLabel englishLabel = new JLabel("英语成绩", JLabel.RIGHT);JTextField englishTextField = new JTextField();JButton updateBtn = new JButton("修改");public UpdateStudentView(MainView mainView, int selectedRowId) {super(mainView, "修改学生信息",true);// 添加各组件到面板上idLabel.setPreferredSize(new Dimension(80, 30));jPanel.add(idLabel);idTextField.setPreferredSize(new Dimension(200, 30));jPanel.add(idTextField);nameLabel.setPreferredSize(new Dimension(80, 30));jPanel.add(nameLabel);nameTextField.setPreferredSize(new Dimension(200, 30));jPanel.add(nameTextField);noLabel.setPreferredSize(new Dimension(80, 30));jPanel.add(noLabel);noTextField.setPreferredSize(new Dimension(200, 30));jPanel.add(noTextField);homeLabel.setPreferredSize(new Dimension(80, 30));jPanel.add(homeLabel);homeTextField.setPreferredSize(new Dimension(200, 30));jPanel.add(homeTextField);chineseLabel.setPreferredSize(new Dimension(80, 30));jPanel.add(chineseLabel);chineseTextField.setPreferredSize(new Dimension(200, 30));jPanel.add(chineseTextField);mathLabel.setPreferredSize(new Dimension(80, 30));jPanel.add(mathLabel);mathTextField.setPreferredSize(new Dimension(200, 30));jPanel.add(mathTextField);englishLabel.setPreferredSize(new Dimension(80, 30));jPanel.add(englishLabel);englishTextField.setPreferredSize(new Dimension(200, 30));jPanel.add(englishTextField);jPanel.add(updateBtn);Container contentPane = getContentPane();contentPane.add(jPanel);setSize(350, 500);setLocationRelativeTo(null);// DISPOSE_ON_CLOSE 只销毁当前窗体setDefaultCloseOperation(DISPOSE_ON_CLOSE);setResizable(false);setVisible(true);}}
1.5 实现数据回显
就是根据传过来的id值，查询数据库，在展示到对应的表单中
1.5.1 接口
Student getById(int selectedRowId);1.5.2 实现类
// 根据 id 查询@Overridepublic Student getById(int selectedRowId) {StringBuilder sql = new StringBuilder();sql.append("select * from detail where id = ?");// 执行Connection connection = null;PreparedStatement preparedStatement = null;ResultSet resultSet = null;Student student = new Student();// 返回的数据try {connection = DBUtil.getConnection();preparedStatement = connection.prepareStatement(sql.toString());preparedStatement.setInt(1, selectedRowId);resultSet = preparedStatement.executeQuery(); // 执行查询返回结果集while (resultSet.next()) {// 遍历查询的每一条记录int id = resultSet.getInt("id");String name = resultSet.getString("name");String no = resultSet.getString("no");String homeTown = resultSet.getString("homeTown");double chinese = resultSet.getDouble("chinese");double math = resultSet.getDouble("math");double english = resultSet.getDouble("english");student.setId(id);student.setName(name);student.setNo(no);student.setHomeTown(homeTown);student.setChinese(chinese);student.setMath(math);student.setEnglish(english);}return student;}catch (Exception e) {e.printStackTrace();} finally {DBUtil.closeRS(resultSet);DBUtil.closePS(preparedStatement);DBUtil.closeConnection(connection);}return null;}1.5.3 在updateStudentView中对返回的结果进行相应的处理
// 查询selectedRowIds对应的数据并回显StudentServiceImpl studentService = new StudentServiceImpl();Student selectedStudent = studentService.getById(selectedRowId);把返回的结果设置到相应的表单中，注意id需设为不可编辑 ，这里只给出了部分，其他的组件也是一样的写法
1.5.4 效果
2. 修改数据
在上面的基础上，对修改数据的模态框进行处理
2.1 给模态框中的修改按钮添加点击事件
2.2 编写事件处理类updateStudentViewHandler
以下代码中给出了框架，具体的逻辑还没实现，具体的实现继续往下看
package com.handler;import com.entity.Student;
import com.service.Impl.StudentServiceImpl;
import com.student_view.MainView;
import com.student_view.UpdateStudentView;import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;/*** @Author：xiexu* @Date：2023/12/18 17:33*/
public class UpdateStudentViewHandler implements ActionListener {private UpdateStudentView updateStudentView;private MainView mainView;public UpdateStudentViewHandler(UpdateStudentView updateStudentView, MainView mainView) {this.updateStudentView = updateStudentView;this.mainView = mainView;}@Overridepublic void actionPerformed(ActionEvent e) {JButton jButton = (JButton) e.getSource();String text = jButton.getText();if ("修改".equals(text)) {.......if (...) {// 重新加载表格查到最新数据mainView.reloadTable();updateStudentView.dispose();} else {// 添加错误，给出提示JOptionPane.showMessageDialog(updateStudentView, "添加失败");}}}
}
2.3 在updateStudentView中实例化
需要传递两个参数，这边将mainView传过去，是便于修改数据成功后，调用reloadTable方法，重新加载表格。
UpdateStudentViewHandler updateStudentViewHandler;updateStudentViewHandler = new UpdateStudentViewHandler(this, mainView);
2.4 实现数据的修改操作逻辑
2.4.1 接口
boolean update(Student student);2.4.2 实现类
// 修改/更新@Overridepublic boolean update(Student student) {StringBuilder sql = new StringBuilder();sql.append("update detail set name=?, no=?, homeTown=?, chinese=?, math=?, english=?");sql.append("where id = ?");// 执行Connection connection = null;PreparedStatement preparedStatement = null;ResultSet resultSet = null;TableDTO tableDTO = new TableDTO(); // 返回的数据try {connection = DBUtil.getConnection();preparedStatement = connection.prepareStatement(sql.toString());preparedStatement.setString(1, student.getName());preparedStatement.setString(2, student.getNo());preparedStatement.setString(3, student.getHomeTown());preparedStatement.setDouble(4, student.getChinese());preparedStatement.setDouble(5, student.getMath());preparedStatement.setDouble(6, student.getEnglish());preparedStatement.setInt(7,student.getId());return preparedStatement.executeUpdate() == 1; // 执行查询返回结果集}catch (Exception e) {e.printStackTrace();} finally {DBUtil.closeRS(resultSet);DBUtil.closePS(preparedStatement);DBUtil.closeConnection(connection);}return false;}2.4.3 补全上述的代码
2.4.4 上述也是需要一个方法将属性值封装成一个对象
public Student builStudent() {Student student = new Student();student.setId(Integer.valueOf(idTextField.getText()));student.setName(nameTextField.getText());student.setNo(noTextField.getText());student.setHomeTown(homeTextField.getText());student.setChinese(Double.parseDouble(chineseTextField.getText()));student.setMath(Double.parseDouble(mathTextField.getText()));student.setEnglish(Double.parseDouble(englishTextField.getText()));return student;}
