jdbcquery.java

使用Java查询数据库的例子。使用Access数据库

/**
 * ClassName:JdbcQuery
 * Description: D:/jdbc/JdbcQuery.java  
 * Copyright:    Copyright (c) 2002
 * Company:
 * @author:Liyunshan
 * @version 1.0
 */

import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import java.sql.*;
public class JdbcQuery extends Applet
{
	String url = "jdbc:odbc:management";
	String user = "";
	String password = "";
	Statement stmt;
	TextField search = new TextField(20);
	Label number = new Label("                          ");
	TextArea result = new TextArea(40, 20);
	String sql;
	public void init()
	{
		search.addTextListener(new searchFor());
		Panel p = new Panel();
		p.add(new Label("输入要查询的学号:"));
		p.add(search);
		p.add(number);
		setLayout(new BorderLayout());
		add(p, BorderLayout.NORTH);
		add(result, BorderLayout.CENTER);
		try
		{
			Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
			Connection con = DriverManager.getConnection(url, user, password);			
			stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
			                         ResultSet.CONCUR_READ_ONLY); 			
		}
		catch(Exception e)
		{
			result.setText(e.getMessage());
		}
	}
	//响应文本框的输入事件
	class searchFor implements TextListener
	{
		public void textValueChanged(TextEvent te)
		{
			ResultSet rs;
			if (search.getText().length() == 0)
			{
				number.setText("");
				result.setText("");
				return;
			}
			try
			{
				//pay attention to ' 
				sql = "select id,name,age, home,department FROM student " +
				    " WHERE id like '%" + search.getText() +
					"%' ORDER BY id";
				rs = stmt.executeQuery(sql);
				rs.last();
				int row = rs.getRow();
				number.setText("当前共有" + row + "条记录");
				rs.beforeFirst();				
				//while(rs.next())
			}
			catch(Exception e)
			{
			  result.setText(search.getText() + "\n");
			  result.append(e.getMessage());
			  return;			  			
			}
			result.setText("");
			try
			{
				while (rs.next())
				{
				  result.append("学号：" + rs.getString(1)+ "，姓名：" +
				                rs.getString(2) + "，年龄：" + rs.getInt(3) +
								"，籍贯：" + rs.getString(4) + "，系别：" +
								 rs.getString(5) + "\n");				  
				}
			}
			catch(Exception e)
			{
				result.setText(e.getMessage());
			}
		} 
	}
	public static void main(String[] args)
	{
		JdbcQuery applet = new JdbcQuery();
		Frame frame = new Frame("按学号进行模糊查询");
		frame.addWindowListener(
		  new WindowAdapter()
		  { 
		    public void windowClosing(WindowEvent e)
		    {
				System.exit(0);
		    }
		  } );
		frame.add(applet, BorderLayout.CENTER);
		frame.setSize(500, 200);
		applet.init();
		applet.start();
		frame.setVisible(true);
	}	
}