huanshu.java

代码是自己我的代码不是网上down的。是自己写的。里面有很多值得学习的知识点。还有一些javabean组件。不算自己写的JAR文件

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.sql.*;
public class Huanshu extends JFrame
{
	ResultSet rs;
	private DBManager db=new DBManager();
	private JPanel centerpanel;
	private JPanel southpanel;
	private JLabel username;
	private JLabel bookname;
	private JLabel date;
	private JLabel comment;

	private JTextField myusername;
    private JComboBox mybookname;
    private JTextField mydate;
    private JTextField mycomment;
	private JButton ok;
	private JButton cancel;
	private JButton clear;
    
	public Huanshu()
	{
	centerpanel=new JPanel(new GridLayout(4,2));
	southpanel=new JPanel(new GridLayout(1,1));
	username=new JLabel("还书者姓名");
	bookname=new JLabel("书  名");
    date=new JLabel("日  期");
	comment=new JLabel("备  注");
	myusername=new JTextField(16);
    mybookname=new JComboBox();
    mydate=new JTextField(16);
    mycomment=new JTextField(16);
	ok=new JButton("确定");
	cancel=new JButton("退出");
	clear=new JButton("清空");
	centerpanel.add(username);
	centerpanel.add(myusername);
	centerpanel.add(bookname);
	centerpanel.add(mybookname);
	centerpanel.add(date);
	centerpanel.add(mydate);
	centerpanel.add(comment);
	centerpanel.add(mycomment);
	southpanel.add(clear);
	southpanel.add(ok);
	southpanel.add(cancel);
	getContentPane().add(centerpanel,"Center");
	getContentPane().add(southpanel,"South");
	setTitle("书籍还入");
	setSize(200,160);
	Dimension screen=getToolkit().getScreenSize();
	setLocation((screen.width-getSize().width)/2,(screen.height-getSize().height)/2);
	String sql;
		sql="select bookname from 书籍借阅信息表 ";
		
		
		 try
		 {
		 	rs=db.getResult(sql);
		 	//rs.first();
		 	while(rs.next())
		 	{
		 	 mybookname.addItem(rs.getString("bookname"));
		 	}
		 }
		 catch(SQLException ex1)
		 {
		 	ex1.printStackTrace();
		 }
		addWindowListener(
			new WindowAdapter()
			{
				public void windowClosing(WindowEvent e)
				{
					System.exit(0);
				}
			
			}
			);
		cancel.addActionListener(
			new ActionListener()
			{
				public void actionPerformed(ActionEvent e)
				{
					dispose();
				}
			}
			);
		ok.addActionListener(
			new ActionListener()
			{
				public void actionPerformed(ActionEvent e)
				{
					BookBorrow();
				}
			}
			);
		clear.addActionListener(
			new ActionListener()
			{
				public void actionPerformed(ActionEvent e)
				{
					BookClear();
				}
			}
			);	
		
		show();
	}

	public void BookBorrow()
	{
		if(myusername.getText().trim().equals(""))
		{
			JOptionPane.showMessageDialog(this,"还书者姓名不能为空！");
			return;
		}
		if(mybookname.getSelectedItem().toString().trim().equals(""))
		{
			JOptionPane.showMessageDialog(this,"书名不能为空！");
			return;
		}
		if(mydate.getText().trim().equals(""))
		{
			JOptionPane.showMessageDialog(this,"还阅日期不能为空！");
			return;
		}
	   //检验是否此人借的次书
	   
	  String strSQL;
	  strSQL="select * from 书籍借阅信息表 where studentname='"+myusername.getText().trim()+"'and bookname='"+mybookname.getSelectedItem().toString().trim()+"'";
	  rs=db.getResult(strSQL);
	  boolean isexist=false;
	  try
	  {
	  	isexist=rs.first();
	  }
	  catch(SQLException ex1){}
	  //若不存在，提示警告信息提醒用户重新输入
	  if(!isexist)
	  {
	  	JOptionPane.showMessageDialog(this,myusername.getText().trim()+"同学并未借得!<"+mybookname.getSelectedItem().toString().trim()+">请确认！");
	  	return ;
	  }
	  
	  //生成更新语句
	  	strSQL="update 书籍借阅信息表 set returndate='"+mydate.getText().trim()+"' ,comment='"+mycomment.getText().trim()+"'where  studentname='"+myusername.getText().trim()+"'and bookname='"+mybookname.getSelectedItem().toString().trim()+"'";
	  
	  	try
	  	{
	  		 if(db.executeSql(strSQL))
	    {
	    	JOptionPane.showMessageDialog(this,"操作成功！");
	    }
	    else
	    {
	    	JOptionPane.showMessageDialog(this,"此借书者不存在！请确认！");
	    }
	  	}
	  	catch(Exception ex)
	  	{
	  		ex.printStackTrace();
	  	}
	   
		
	}
	public void BookClear()
	{
		myusername.setText("");
		mybookname.setSelectedItem("");
		mydate.setText("");
		mycomment.setText("");
	}
	public static void main(String[] args)
	{
		new Huanshu();
	}
}