jp2.java

java开发的公交查询系统

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.sql.*;
class Jp2 extends JPanel
{
	JPanel jp1,jp2,jp3,jpl,jpr;
	JLabel jl1,jl2;
	JButton jb1;
	JTextField jt1;
	JTextArea jta;
	static String array[]=new String[50];
	public Jp2()
	{
		jp1=new JPanel();
		jp2=new JPanel();
		jp3=new JPanel();
		jpl=new JPanel();
		jpr=new JPanel();
		jl1=new JLabel("公交路线查询");
		jl2=new JLabel("线路");
		jl1.setHorizontalAlignment(SwingConstants.CENTER);
		jb1=new JButton("查询");
		jt1=new JTextField();
		jta=new JTextArea();
		jta.setBorder(jt1.getBorder());
		jt1.setColumns(10);
		jl1.setFont(new java.awt.Font("楷体", 0, 12));
		jl2.setFont(new java.awt.Font("楷体", 0, 12));
		jb1.setFont(new java.awt.Font("楷体", 0, 12));
		jpl.setLayout(new GridLayout(3,1));
		jpr.setLayout(new GridLayout(1,1));
		jp1.setLayout(new GridLayout(1,1));
		this.setLayout(new GridLayout(1,2));
		jp1.add(jl1);
		jpl.add(jp1);
		jp2.add(jl2);
		jp2.add(jt1);
		jpl.add(jp2);
		jp3.add(jb1);
		jpl.add(jp3);
		jpr.add(jta);
		this.add(jpl);
		this.add(jpr);
		jb1.addActionListener(new JBL());
	}
		public class JBL implements ActionListener
	{
		public void actionPerformed(ActionEvent e1)
		{
			if(e1.getSource()==jb1)
			{
				int length;
				String result="";
				String line_name=jt1.getText();
				if(line_name.equals(""))
				{
					JOptionPane.showMessageDialog(Jp2.this," 站点不能为空","标题",JOptionPane.INFORMATION_MESSAGE);
				}
				else
				{
				
				String query="select stop_name from stops where stop_id IN( "
							+"select stop_id from linesstops where line_id IN( "
							+"select line_id from lines where line_name = '"+line_name+"'))";
				length=execute(query);
				for(int i=0;i<length;i++)
				{
					result+=array[i]+" ";
				}
				jta.setText("");
				jta.append("经过"+line_name+"的车站是:\n");
				jta.append(result+" ");
				if(line_name==" ")
				JOptionPane.showMessageDialog(Jp2.this,"不能为空","标题",JOptionPane.INFORMATION_MESSAGE);
			}
			}
		}
	}
	public int execute(String query)
	{
		String dbDriver = "sun.jdbc.odbc.JdbcOdbcDriver";
        String url = "jdbc:odbc:liu";
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        
        int i=0;
        try
        {
            Class.forName(dbDriver);
            conn = DriverManager.getConnection(url);
            stmt=conn.createStatement();
            rs=stmt.executeQuery(query);
            while (rs.next())
            {
            	String temp=rs.getString(1);
            	array[i]=temp;
            	i++;
            }
			rs.close();
			stmt.close();
			conn.close();
			
        } 
        catch (Exception ee)
        {
        	System.out.println("33 "+ee);
        }
        return i;
	}	
}