zuanye.java

创建一个数据库dbstu,其中包括下列表： １.student(学号

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

public class Zuanye extends JFrame implements ActionListener{
	 static int Acc=0;
	  String url = "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=dbstu";
        Connection con;
        Statement stmt;
       
	ResultSet rs;
		JTextField t1=new JTextField(15);
	JTextField t2=new JTextField(15);

	JLabel l1=new JLabel("输入专业名称:");
	JLabel l2=new JLabel("统计专业人数:");
	JButton btn=new JButton("统计");JButton aa=new JButton("退出");
	public Zuanye(){
		Container con=getContentPane();
		con.setLayout(new GridLayout(3,1));
	JPanel p1=new JPanel();
	p1.add(l1);p1.add(t1);
	JPanel p2=new JPanel();
	p2.add(l2);p2.add(t2);
	JPanel p3=new JPanel();
	p2.add(btn);p2.add(aa);
	btn.addActionListener(this);aa.addActionListener(this);
	con.add(p1);con.add(p2);con.add(p3);		
		setTitle("统计专业的学生人数");
		setSize(300,200);
        setLocation(200,200);
		setVisible(true);



	}
		public void actionPerformed(ActionEvent e){
			if(e.getSource()==aa){
				dispose();
		//	System.exit(0);
				}
			 else if(e.getSource()==btn)	
			{
			
	 
	try {
        	
           Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
        } catch(java.lang.ClassNotFoundException eaa) {
            System.err.print("ClassNotFoundException: ");
            System.err.println(eaa.getMessage());
        }

        try {	      
            con = DriverManager.getConnection(url, "sa", "");
			stmt = con.createStatement();
	
			
			PreparedStatement updateSales;
		
		
	String	sql ="SELECT * FROM student WHERE 专业=?";
	updateSales = con.prepareStatement(sql);
				updateSales.setString(1, t1.getText());
	
			
			
			rs=updateSales.executeQuery();
		
	while(rs.next()){
			Acc+=1;}
			System.out.println("专业学生人数="+Acc);	
	t2.setText(Integer.toString(Acc));
if(Acc>0)JOptionPane.showMessageDialog(null,"成功");
else  JOptionPane.showMessageDialog(null,"该专业不存在");
	Acc=0;
		} catch(SQLException ex) {
            System.err.println("SQLException: " + ex.getMessage());
        } }
        }
  // public static void main(String args[]){ 	
     //  new Zuanye();	
        
//	}
			

}