deletepane.java

这是一个超市管理系统

package file2;
import java.sql.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class DeletePane extends JPanel implements ActionListener{
	//声明数据库连接组件
	private DBConnection con=null;
	private JLabel tip=null;
	private JLabel name=null;
	private JLabel password=null;
	private JTextField nameTextField=null;
	private JTextField passwordTextField=null;
	private JButton query=null;
	private JButton delete=null;
	private JButton reset=null;
	private JPanel tipPane=null;
	private JPanel nameAndPasswordPane=null;
	private JPanel buttonsPane=null;
	private JPanel echoPane=null;//装载nameAndPasswordPane和buttonsPane
	public DeletePane(){
		tip=new JLabel("请在下面输入要删除的管理员信息:");
		name=new JLabel("名字");
		password=new JLabel("密码");
		nameTextField=new JTextField(20);
		passwordTextField=new JTextField(20);
		query=new JButton("查询");
		delete=new JButton("删除");
		reset=new JButton("重置");
		tipPane=new JPanel();
		tipPane.setLayout(new FlowLayout(FlowLayout.CENTER));
		tipPane.add(tip);
		//声明nameAndPasswordPane并在其中装载组件
		nameAndPasswordPane=new JPanel();
		nameAndPasswordPane.setLayout(new GridLayout(2,2));
		nameAndPasswordPane.add(name);
		nameAndPasswordPane.add(nameTextField);
		nameAndPasswordPane.add(password);
		nameAndPasswordPane.add(passwordTextField);
		//声明buttonsPane组件并在其中装载组件
		buttonsPane=new JPanel();
		buttonsPane.setLayout(new FlowLayout(FlowLayout.CENTER));
		buttonsPane.add(query);
		buttonsPane.add(delete);
		buttonsPane.add(reset);
		//声明echoPane并在其中装载组件
		echoPane=new JPanel();
		echoPane.setLayout(new GridLayout(2,1));
		echoPane.add(nameAndPasswordPane);
		echoPane.add(buttonsPane);
		this.setLayout(new GridLayout(2,1));
		this.add(tipPane);
		this.add(echoPane);
		//初始状态"query"按钮为可用，"delete"按钮为不可用，"reset"按钮为可用
		query.setEnabled(true);
		delete.setEnabled(false);
		reset.setEnabled(true);
		query.addActionListener(this);
		delete.addActionListener(this);
		reset.addActionListener(this);
		
	}
	public void actionPerformed(ActionEvent e){
		if(e.getSource()==reset){
			nameTextField.setText("");
			passwordTextField.setText("");
			query.setEnabled(true);
			delete.setEnabled(false);
			reset.setEnabled(true);
			return;
		}
		if(e.getSource()==query){
			String name=nameTextField.getText().trim();
			String password=passwordTextField.getText().trim();
			if(name.equals("")||password.equals("")){
				JOptionPane.showMessageDialog(null, " 用户名和密码都不能为空，请您重新输入.", "警告", JOptionPane.ERROR_MESSAGE);
				return;
			}
			String querySql="select* from administrator where administrator='"+name+"' and password='"+password+"'";
			con=new DBConnection();
			ResultSet rs=con.executeSelect(querySql);
			try{
				if(!rs.next()){
					JOptionPane.showMessageDialog(null, "该管理员不存在,请您重新输入.", "警告", JOptionPane.ERROR_MESSAGE);
					return;
				}
			}catch(SQLException sql){
				JOptionPane.showMessageDialog(null, "发生SQL错误!", "提示", JOptionPane.ERROR_MESSAGE);
				return;
			}
			try{
				nameTextField.setText(rs.getString("administrator"));
				passwordTextField.setText(rs.getString("password"));
				nameTextField.setEditable(false);
				passwordTextField.setEditable(false);
				query.setEnabled(false);
				delete.setEnabled(true);
				reset.setEnabled(false);
				return;
			}catch(SQLException sql){
				JOptionPane.showMessageDialog(null, "发生SQL错误!", "提示", JOptionPane.ERROR_MESSAGE);
				return;
			}
			
		}
		if(e.getSource()==delete){
			String name=nameTextField.getText().trim();
			String password=passwordTextField.getText().trim();
			String deleteSql="delete from administrator where administrator='"+name+"' and password='"+password+"'";
			int option=JOptionPane.showConfirmDialog(null, "您真的要删除该管理员吗?", "确认", JOptionPane.YES_NO_OPTION);
			if(option==JOptionPane.YES_OPTION){
				con.executeDML(deleteSql);
				JOptionPane.showMessageDialog(null, "删除成功!", "通告", JOptionPane.INFORMATION_MESSAGE);
				query.setEnabled(true);
				delete.setEnabled(false);
				reset.setEnabled(true);
				nameTextField.setEditable(true);
				passwordTextField.setEditable(true);
				nameTextField.setText("");
				passwordTextField.setText("");
				return;
			}
			JOptionPane.showMessageDialog(null, "您没有删除该管理员!", "通告", JOptionPane.INFORMATION_MESSAGE);
			query.setEnabled(true);
			delete.setEnabled(false);
			reset.setEnabled(true);
			nameTextField.setEditable(true);
			passwordTextField.setEditable(true);
			nameTextField.setText("");
			passwordTextField.setText("");
			return;
		}
	}
}