deleteitemfromsecondcatalog.java

这是一个超市管理系统

package file2;
import java.awt.*;
import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.sql.*;
public class DeleteItemFromSecondCatalog extends JPanel implements ActionListener,ItemListener{
	private DBConnection con=null;//声明数据库连接组件
	private JComboBox comboBoxFirst=null;
	private JComboBox comboBoxSecond=null;
	private JLabel first=new JLabel("请选择商品大类:");
	private JLabel second=new JLabel("请选择商品明细类:");
	private JButton delete=null;
	private JPanel comboBoxPane=null;
	private JPanel buttonsPane=null;
	private String[] dataSecond=new String [1000];
	public DeleteItemFromSecondCatalog(){
		try{
			delete=new JButton("删除");
			con=new DBConnection();
			String queryStr="select* from First_Catalog ";
			ResultSet rs=con.executeSelect(queryStr);
			int size=0;
			while(rs.next()){
				size++;
			}
			if(size==0){
				JOptionPane.showMessageDialog(null, "数据库中没有任何商品大类!", "提示", JOptionPane.ERROR_MESSAGE);
				delete.setEnabled(false);
			}
			String[] dataFirst=new String[size+1];
			dataFirst[0]="";
			int count=1;
			rs=null;
			rs=con.executeSelect(queryStr);
			while(rs.next()){
				int ID=rs.getInt(1);
				String name=rs.getString(2);
				dataFirst[count++]=name;
			}
			comboBoxFirst=new JComboBox(dataFirst);
			comboBoxPane=new JPanel();
			comboBoxPane.setLayout(new FlowLayout());
			comboBoxPane.add(first);
			comboBoxPane.add(comboBoxFirst);
			comboBoxPane.add(second);
			comboBoxSecond=new JComboBox();
			dataSecond[0]="";
			comboBoxSecond.addItem(dataSecond[0]);
			comboBoxPane.add(comboBoxSecond);
			buttonsPane=new JPanel();
			buttonsPane.setLayout(new FlowLayout(FlowLayout.CENTER));
			buttonsPane.add(delete);
			this.setLayout(new GridLayout(2,1));
			this.add(comboBoxPane);
			this.add(buttonsPane);
			comboBoxFirst.addItemListener(this);
			delete.addActionListener(this);
		}catch(Exception e){
			//e.printStackTrace();
			JOptionPane.showMessageDialog(null, "发生错误!", "提示", JOptionPane.ERROR_MESSAGE);
		}
		//return;
	}
	public void actionPerformed(ActionEvent e){
		if(e.getSource()==delete){
			try{
				String nameFirst=(String)comboBoxFirst.getSelectedItem();
				String nameSecond=(String)comboBoxSecond.getSelectedItem();
				if(nameFirst==null){
					JOptionPane.showMessageDialog(null, "请您选择商品大类", "提示",JOptionPane.ERROR_MESSAGE);
					return;
				}else{
					if(nameFirst.equals("")){
						JOptionPane.showMessageDialog(null, "请您选择商品大类", "提示",JOptionPane.ERROR_MESSAGE);
						return;
					}
				}
				if(nameSecond==null){
					JOptionPane.showMessageDialog(null, "请您选择明细类", "提示",JOptionPane.ERROR_MESSAGE);
					return;
				}else{
					if(nameSecond.equals("")){
						JOptionPane.showMessageDialog(null, "请您选择明细类", "提示",JOptionPane.ERROR_MESSAGE);
						return;
					}
				}
				int confirm=JOptionPane.showConfirmDialog(null,"您确认要删除 "+nameSecond+" 吗?","确认",JOptionPane.YES_NO_OPTION);
				if(confirm==JOptionPane.YES_OPTION){
					String queryStr1="select Second_ID from Second_Catalog where Second_name='"+nameSecond+"'";
					ResultSet set1=con.executeSelect(queryStr1);
					int IDSecond=0;
					if(set1.next()){
						IDSecond=set1.getInt(1);
					}
					String deleteStr1="delete from Second_Catalog where Second_name='"+nameSecond+"'";
					con.executeDML(deleteStr1);
					//删除Second_Catalog 表中的相应记录
					String queryStr3="select Third_ID from Third_Catalog where To_Second_ID="+
					IDSecond;
					ResultSet set3=con.executeSelect(queryStr3);
					while(set3.next()){
						int id=set3.getInt(1);
						String queryStr2="select* from operationRecord where To_Third_ID="+id;
						ResultSet set4=con.executeSelect(queryStr2);
						if(set4.next()){
							con.executeDML("delete from operationRecord where To_Third_ID="+id);
						}	
					}
					con.executeDML("delete from Third_Catalog where To_Second_ID="+IDSecond);
					JOptionPane.showMessageDialog(null, "删除成功!", "提示", JOptionPane.INFORMATION_MESSAGE);
					//return;
					comboBoxSecond.removeAllItems();
					comboBoxSecond.addItem(dataSecond[0]);
					comboBoxFirst.setSelectedIndex(0);
					comboBoxFirst.updateUI();
					//addCount=0;
				}
			}catch(Exception excep){
				//excep.printStackTrace();
				JOptionPane.showMessageDialog(null, "发生错误!", "提示", JOptionPane.ERROR_MESSAGE);
				return;
			}
		}
	}
	public void itemStateChanged(ItemEvent e){
				if(e.getStateChange()==ItemEvent.SELECTED){
					delete.setEnabled(true);
					comboBoxSecond.removeAllItems();
					String nameFirst=(String)comboBoxFirst.getSelectedItem();
					String queryFirst="select First_ID from First_Catalog where First_name='"+nameFirst+"'";
					ResultSet set=con.executeSelect(queryFirst);
					int first_ID=0;
					try{
						if(set.next()){
							first_ID=set.getInt(1);
						}				
						String querySecond="select Second_name from Second_Catalog where To_First_ID="+first_ID;
						set=null;
						set=con.executeSelect(querySecond);
						int count=1;
						if(!set.next()){
							JOptionPane.showMessageDialog(null,"该商品大类目前还没有明细类!" , "提示", JOptionPane.INFORMATION_MESSAGE);
							delete.setEnabled(false);
						}
						set=null;
						set=con.executeSelect(querySecond);
						while(set.next()){
							dataSecond[count++]=set.getString(1);
						}
						for(int addNum=1;addNum<count;addNum++){
							comboBoxSecond.addItem(dataSecond[addNum]);
						}
					}catch(Exception excep){
					//excep.printStackTrace();
						//JOptionPane.showMessageDialog(null, "发生错误!", "提示", JOptionPane.INFORMATION_MESSAGE);
					}
					return;
				}
					
	}
}