java写一个连接数据库中商品库存管理中查询功能的页面（中文注释）

下面是一个简单的Java商品库存管理系统的查询功能页面的示例代码，包括连接数据库和中文注释：

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

public class ProductSearch extends JFrame implements ActionListener {

    // 定义GUI组件
    JLabel nameLabel, categoryLabel;
    JTextField nameField, categoryField;
    JButton searchButton, resetButton;
    JTable resultTable;

    // 定义数据库连接相关变量
    Connection conn;
    Statement stmt;
    ResultSet rs;

    public ProductSearch() {
        // 初始化GUI组件
        nameLabel = new JLabel("商品名称：");
        nameField = new JTextField(20);
        categoryLabel = new JLabel("商品类别：");
        categoryField = new JTextField(20);
        searchButton = new JButton("查询");
        resetButton = new JButton("重置");
        resultTable = new JTable();

        // 设置GUI布局
        JPanel inputPanel = new JPanel(new GridLayout(2, 2));
        inputPanel.add(nameLabel);
        inputPanel.add(nameField);
        inputPanel.add(categoryLabel);
        inputPanel.add(categoryField);

        JPanel buttonPanel = new JPanel(new FlowLayout());
        buttonPanel.add(searchButton);
        buttonPanel.add(resetButton);

        JPanel mainPanel = new JPanel(new BorderLayout());
        mainPanel.add(inputPanel, BorderLayout.NORTH);
        mainPanel.add(buttonPanel, BorderLayout.CENTER);
        mainPanel.add(new JScrollPane(resultTable), BorderLayout.SOUTH);

        // 添加事件监听器
        searchButton.addActionListener(this);
        resetButton.addActionListener(this);

        // 连接数据库
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/inventory", "root", "password");
            stmt = conn.createStatement();
        } catch (Exception ex) {
            ex.printStackTrace();
        }

        // 设置窗口属性
        setTitle("商品查询");
        setContentPane(mainPanel);
        pack();
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);
    }

    // 处理按钮点击事件
    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == searchButton) {
            // 执行查询操作
            String name = nameField.getText();
            String category = categoryField.getText();
            try {
                String sql = "SELECT * FROM products WHERE name LIKE '%" + name + "%' AND category LIKE '%" + category + "%'";
                rs = stmt.executeQuery(sql);
                resultTable.setModel(buildTableModel(rs));
            } catch (Exception ex) {
                ex.printStackTrace();
            }
        } else if (e.getSource() == resetButton) {
            // 重置查询条件
            nameField.setText("");
            categoryField.setText("");
            resultTable.setModel(new DefaultTableModel());
        }
    }

    // 将ResultSet转换成TableModel
    public static DefaultTableModel buildTableModel(ResultSet rs) throws SQLException {
        ResultSetMetaData metaData = rs.getMetaData();
        // 获取列数
        int columnCount = metaData.getColumnCount();
        // 获取列名
        String[] columnNames = new String[columnCount];
        for (int i = 1; i <= columnCount; i++) {
            columnNames[i - 1] = metaData.getColumnName(i);
        }
        // 获取行数据
        Object[][] data = new Object[100][columnCount];
        int rowCount = 0;
        while (rs.next()) {
            Object[] row = new Object[columnCount];
            for (int i = 1; i <= columnCount; i++) {
                row[i - 1] = rs.getObject(i);
            }
            data[rowCount++] = row;
        }
        return new DefaultTableModel(data, columnNames);
    }

    public static void main(String[] args) {
        new ProductSearch();
    }
}

这段代码在前面的示例基础上增加了连接数据库的功能。首先在构造函数中连接数据库，然后在查询按钮的事件处理方法中执行查询操作，将查询结果转换成TableModel并显示在表格中。注意，这里的查询操作需要根据实际的数据库表结构和查询条件进行调整。