bookdelete.java.bak

网上图书管理系统(java)用Web方法开发的管理系统挂接在电子系网站上

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.sql.*;
public class BookDelete extends JFrame implements ActionListener
{
	DataBaseManager db=new DataBaseManager();
	ResultSet rs;
	Container c;
	JLabel TipLabel=new JLabel("请输入要删除的书名：",JLabel.CENTER);
	JTextField BookDeleteTextField=new JTextField(15);
	JButton YesBtn,ExitBtn;
	JPanel panel1=new JPanel();
	public BookDelete()
	{
		super("删除书籍信息");
		c=getContentPane();
		c.setLayout(new BorderLayout());
		c.add(TipLabel,BorderLayout.NORTH);
		c.add(BookDeleteTextField,BorderLayout.CENTER);
		YesBtn=new JButton("确定");
		ExitBtn=new JButton("退出");
		YesBtn.addActionListener(this);
		ExitBtn.addActionListener(this);
		panel1.add(YesBtn);
		panel1.add(ExitBtn);
		c.add(panel1,BorderLayout.SOUTH);
	}
	public void actionPerformed(ActionEvent e)
	{
		if(e.getSource()==ExitBtn)
		{
			this.dispose();
		}
		else if(e.getSource()==YesBtn)
		{
			try
			{
			String strSQL="select borrowed_count from books where bookName='"+
			BookDeleteTextField.getText().trim()+"'";
			rs=db.getResult(strSQL);
			if(!rs.first())
			{
				JOptionPane.showMessageDialog(null,"书库里没有你要删除的书！");
			}
			else
			{
				String strSql="delete books where bookName='"+
				BookDeleteTextField.getText().trim()+"'and borrowed_count=0";
				rs.first();
				int count=rs.getInt(1);
				if(!(count==0))
				{
					JOptionPane.showMessageDialog(null,"此书还有学生没有还！\n现在还不能从书库中删除。。。");
					this.dispose();
				}
				else if(db.updateSql(strSQL))
				{
					JOptionPane.showMessageDialog(null,"删除成功！");
					db.closeConnection();
					this.dispose();
				}
				else
				{
					JOptionPane.showMessageDialog(null,"删除失败！");
					db.closeConnection();
					this.dispose();
				}
			}
		}
		catch(SQLException sqle)
	        {
		    System.out.println(sqle.toString());
	        }
	        catch(Exception ex)
	        {
		    System.out.println(ex.toString());
	        }
		}
	}
}