java 连接数据库摸板

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

import javax.swing.JButton;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import java.sql.*;

public class DbQueryBean extends JPanel {

    private static final long serialVersionUID = 1L;

    private JTextArea textArea;

    private JTextField textField;

    private String url = null;

    private String strSql = null;

    private String strDriver = null;

    private Connection conn = null;

    private ResultSet result = null;

    private Statement statement = null;

    /**
     * Create the panel
     */
    public DbQueryBean() {
        super();
        setLayout(null);

        textField = new JTextField();
        textField.addActionListener(new ActionListener() {
            public void actionPerformed(final ActionEvent e) {
                dbConnection();
                dbQuery();
                dbClose();
            }
        });
        textField.setBounds(10, 10, 365, 25);
        add(textField);

        final JButton button = new JButton();
        button.addActionListener(new ActionListener() {
            public void actionPerformed(final ActionEvent e) {
                dbConnection();
                dbQuery();
                dbClose();
            }
        });
        button.setText("执行");
        button.setBounds(405, 10, 60, 25);
        add(button);

        final JScrollPane scrollPane = new JScrollPane();
        scrollPane.setBounds(10, 62, 480, 303);
        add(scrollPane);

        textArea = new JTextArea();
        scrollPane.setViewportView(textArea);
        //

    }

    public void dbConnection() {

        try {
            Class.forName(strDriver);
            conn = DriverManager.getConnection(url);
        } catch (Exception e) {
            e.printStackTrace();
            JOptionPane.showMessageDialog(null, "连接数据库出错", "error!",
                    JOptionPane.ERROR_MESSAGE);
        }
    }

    public void dbQuery() {
        strSql = textField.getText().trim();
        String strData = "";
        try {
            statement = conn.createStatement();
            result = statement.executeQuery(strSql);
            ResultSetMetaData meta = result.getMetaData();
            int colCount = meta.getColumnCount(); // 得到表中的列数

            for (int i = 1; i <= colCount; i++) {
                strData += "        " + meta.getColumnName(i).trim(); // 得到标题

                                                                        // trim()是除去前后的空格

            }
            strData += "\n";

            while (result.next()) {
                for (int i = 1; i <= colCount; i++) {
                    strData += "        " + result.getString(i).trim(); // 得到每一行的数据

                }
                strData += "\n";
            }
        } catch (Exception e) {
            e.printStackTrace();
            JOptionPane.showMessageDialog(null, "数据库查询出错", "error!",
                    JOptionPane.ERROR_MESSAGE);
        }

        textArea.setText(strData);
    }

    public void dbClose() {
        try {
            statement.close();
            conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
            JOptionPane.showMessageDialog(null, "关闭数据库出错", "error!",
                    JOptionPane.ERROR_MESSAGE);
        }

    }

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    public void clearTextArea() {
        textArea.setText("");
    }

    public String getStrDriver() {
        return strDriver;
    }

    public void setStrDriver(String strDriver) {
        this.strDriver = strDriver;
    }

}