example10_8.java.bak

书中的例题

/* 动态选择加载驱动程序的类型 */
import java.sql.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
  class Example10_8
{
	public static void main(String args[])
	{
		JFrame dataframe=new ConnectFrame();
		dataframe.show();
	}
}
class ConnectFrame extends JFrame implements ActionListener
{
  private Connection con=null;
  private Statement stmt=null;
  private JTextField url=new JTextField(10);
  private JTextField driver=new JTextField(10);
  private JTextField username=new JTextField(10);
  private JTextField password=new JTextField(10);
  private JTextArea resultarea=new JTextArea(6,30);
  private JButton submit=new JButton("连接");
  private JLabel statelabel=new JLabel("连接数据库的状态如下",SwingConstants.LEFT);
  private JLabel urllabel=new JLabel("数据库URL",SwingConstants.LEFT);
  private JLabel driverlabel=new JLabel("驱动程序",SwingConstants.LEFT);
  private JLabel userlabel=new JLabel("用户名",SwingConstants.LEFT);
  private JLabel pwdlabel=new JLabel("密码",SwingConstants.LEFT);

 public ConnectFrame()
  {
	 setTitle("数据库连接");
	 setSize(440,300);
	 addWindowListener(new WindowAdapter()
		{
		 public void windowClosing(WindowEvent e)
		  {
			 System.exit(0);
		 }
	 });
	 resultarea.setEditable(false);
	 resultarea.setLineWrap(true);
	 Container c=getContentPane();
	 c.setLayout(null);
	 c.add(urllabel);
	 urllabel.setBounds(10,10,80,22);
	 c.add(url);
	 url.setBounds(100,10,240,22);
	 c.add(driverlabel);
	 driverlabel.setBounds(10,40,80,22);
	 c.add(driver);
	 driver.setBounds(100,40,240,22);
	 c.add(userlabel);
	 userlabel.setBounds(10,70,80,22);
	 c.add(username);
	 username.setBounds(100,70,240,22);
	 c.add(pwdlabel);
	 pwdlabel.setBounds(10,100,80,22);
	 c.add(password);
	 password.setBounds(100,100,240,22);
	 c.add(submit);
	 submit.setBounds(355,60,60,25);
	 c.add(statelabel);
	 statelabel.setBounds(140,135,150,22);
	 JScrollPane scrollpane=new JScrollPane(resultarea);
	 c.add(scrollpane);
	 scrollpane.setBounds(100,160,300,100);
	 submit.addActionListener(this);
	 driver.setNextFocusableComponent(username);
	 password.setNextFocusableComponent(submit);
	 submit.setNextFocusableComponent(url);
 }
 public void actionPerformed(ActionEvent evt)
	{ 
	 try{
		 resultarea.setText("");
		 Class.forName(driver.getText().trim());
		 resultarea.append("驱动程序已加载，即将连接数据库"+"\n");
		 con=DriverManager.getConnection(url.getText().trim(),
		                       username.getText().trim(),
		                       password.getText().trim(),  );
		 DatabaseMetaData dmd=con.getMetaData();
		 resultarea.append("已连接到数据库:"+dmd.getURL()+"\n");
		 resultarea.append("所用的驱动程序:"+dmd.getDriverName()+"\n");
	   }
	 catch(Exception ex)
	  {
		resultarea.append(ex.getMessage());
	  }
  }
}