bookdb.java

这是个简单的在线书店购书系统

package mypack;
import java.sql.*;
import java.util.*;
import java.lang.*;

public class BookDB {
	 
  String driver="com.microsoft.jdbc.sqlserver.SQLServerDriver";
  String user="sa";
  String pwd="sa";
  String url="jdbc:microsoft:sqlserver://localhost:1433;databaseName=pubs";
  private Connection con;
private Connection getCon() {
	try{
		 Class.forName(driver);
		 Connection con=DriverManager.getConnection(url, user, pwd);
 		return con;
	}catch(Exception e){
		e.printStackTrace();
	}
	return null;
}
  

//获取一本图书信息
//参数：图书编号；返回类型：bookbean对象
public BookBean getBook(String  id ){
	try{
		String sql="select *from books where id="+id;
		Connection con=getCon();
		Statement stm=con.createStatement();
		BookBean book=null;
		ResultSet rs=stm.executeQuery(sql);
		
		while(rs.next()){
			String bookid=rs.getString(1);
			String name=rs.getString(2);
			String title=rs.getString(3);
			float price=rs.getFloat(4);
			int yr=rs.getInt(5);
			String description=rs.getString(6);
			int saleAmount=rs.getInt(7);
			book=new BookBean(bookid,name,title,price,yr,description,saleAmount);
			}
		rs.close();
		stm.close();
		con.close();
		return book;
	
	}catch(Exception e){
		e.printStackTrace();
	}
	return null;
}
//获取所有的图书信息
//　　参数：无；返回类型：vector
public Vector getBooks(){
		try{
			String sql="select * from books";
			Connection con=getCon();
			Statement stm=con.createStatement();
			ResultSet rs=stm.executeQuery(sql);
			Vector v=new Vector();
			
			while(rs.next()){
				String bookid=rs.getString(1);
				String name=rs.getString(2);
				String title=rs.getString(3);
				float price=rs.getFloat(4);
				int yr=rs.getInt(5);
				String description=rs.getString(6);
				int saleAmount=rs.getInt(7);
				BookBean book=new BookBean(bookid,name,title,price,yr,description,saleAmount);
				v.add(book);
			}
			return v;
		}catch(Exception e){
			e.printStackTrace();
		}
	return null;
}
//添加一本书
//参数：一本图书信息bookbean对象；返回类型boolean，代表是否添加成功
public boolean addBook(BookBean book){
	try{
		
		   Connection con=getCon();
		   String sql="insert books Values(?,?,?,?,?,?,?)";//变量
		   PreparedStatement pstm=con.prepareStatement(sql);//传参
		   pstm.setString(1,book.getId());//通过book对象给id　赋值
		   pstm.setString(2,book.getName());
		   pstm.setString(3,book.getTitle());
		   pstm.setFloat(4,book.getPrice());
		   pstm.setInt(5,book.getYr());
		   pstm.setString(6,book.getDescription());
		   pstm.setInt(7,book.getSaleAmount());
		   
		  int flg= pstm.executeUpdate();
		pstm.close();
		con.close();
		if(flg!=0){return true;}
	}catch(Exception e){
			e.printStackTrace();
		}
	return false;
}
public boolean delBook(String id){
	try{
		String sql="delete from books where id="+id;
		Connection con=getCon();
		Statement stm=con.createStatement();
		
		int flg=stm.executeUpdate(sql);
	if(flg!=0){return true;}
	
}catch(Exception e){
	e.printStackTrace();
}
return false;
}
}