java swing 查询数据库显示在面板里代码示例

以下是一个简单的 Java Swing 应用程序，它可以查询数据库并将结果显示在面板中：

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

public class DatabaseViewer extends JFrame implements ActionListener {
    private static final String DB_URL = "jdbc:mysql://localhost:3306/mydatabase";
    private static final String DB_USER = "root";
    private static final String DB_PASS = "password";

    private JLabel lblName, lblAge, lblAddress;
    private JTextField tfName, tfAge, tfAddress;
    private JButton btnSearch;
    private JTextArea taResult;

    public DatabaseViewer() {
        super("Database Viewer");

        // Create UI components
        lblName = new JLabel("Name:");
        lblAge = new JLabel("Age:");
        lblAddress = new JLabel("Address:");
        tfName = new JTextField(20);
        tfAge = new JTextField(20);
        tfAddress = new JTextField(20);
        btnSearch = new JButton("Search");
        btnSearch.addActionListener(this);
        taResult = new JTextArea(10, 30);
        taResult.setEditable(false);
        taResult.setBorder(new LineBorder(Color.GRAY));

        // Create layout
        JPanel pInput = new JPanel(new GridLayout(3, 2, 5, 5));
        pInput.add(lblName);
        pInput.add(tfName);
        pInput.add(lblAge);
        pInput.add(tfAge);
        pInput.add(lblAddress);
        pInput.add(tfAddress);
        JPanel pButton = new JPanel();
        pButton.add(btnSearch);
        JPanel pResult = new JPanel(new BorderLayout());
        pResult.add(new JScrollPane(taResult), BorderLayout.CENTER);
        pResult.setBorder(new TitledBorder("Search Result"));
        JPanel pMain = new JPanel(new BorderLayout());
        pMain.add(pInput, BorderLayout.NORTH);
        pMain.add(pButton, BorderLayout.CENTER);
        pMain.add(pResult, BorderLayout.SOUTH);

        // Set frame properties
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationRelativeTo(null);
        setContentPane(pMain);
        pack();
        setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == btnSearch) {
            String name = tfName.getText().trim();
            String age = tfAge.getText().trim();
            String address = tfAddress.getText().trim();
            searchDatabase(name, age, address);
        }
    }

    private void searchDatabase(String name, String age, String address) {
        try {
            // Load the driver class
            Class.forName("com.mysql.jdbc.Driver");

            // Establish the connection
            Connection conn = DriverManager.getConnection(DB_URL, DB_USER, DB_PASS);

            // Create the SQL statement
            String sql = "SELECT * FROM people WHERE 1=1";

            if (!name.isEmpty()) {
                sql += " AND name LIKE '%" + name + "%'";
            }

            if (!age.isEmpty()) {
                sql += " AND age = " + age;
            }

            if (!address.isEmpty()) {
                sql += " AND address LIKE '%" + address + "%'";
            }

            // Execute the query
            Statement stmt = conn.createStatement();
            ResultSet rs = stmt.executeQuery(sql);

            // Process the results
            taResult.setText("");
            while (rs.next()) {
                String result = "Name: " + rs.getString("name") + "\n" +
                                "Age: " + rs.getInt("age") + "\n" +
                                "Address: " + rs.getString("address") + "\n\n";
                taResult.append(result);
            }

            // Close the resources
            rs.close();
            stmt.close();
            conn.close();
        } catch (Exception ex) {
            ex.printStackTrace();
            JOptionPane.showMessageDialog(this, "Error: " + ex.getMessage(), "Error", JOptionPane.ERROR_MESSAGE);
        }
    }

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

这个应用程序使用了 MySQL 数据库，你需要将 `DB_URL`、`DB_USER` 和 `DB_PASS` 替换为你自己的数据库连接信息。在 `searchDatabase` 方法中，我们使用 JDBC API 执行 SQL 查询，并处理结果集以在文本区域中显示查询结果。注意，我们在 SQL 语句中使用了 `LIKE` 操作符来模糊搜索名字和地址。