returndb.java

本系统完成简单的图书管理系统

/***********************************************************************
*                          湖南大学图书管理系统
* @author Administrator                                                         
* @since 2008.06                                                  
* @version 1.0                                                           															  
* @category 还书数据库操作
*************************************************************************/

package library.DBaccess;


import java.sql.Connection;
import java.sql.Date;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Calendar;

import library.DBBase.JDBC;

public class ReturnDB {

	public ReturnDB() {
		// TODO Auto-generated constructor stub
		super();
	}
	
	
	public void ReturnBook(String isbn, String username) {
		String userid = null;
		String bookclassid = null;
		int count = 0;

		JDBC jdbc = new JDBC();
		Connection con = jdbc.getConnection();

		String sql = "select USERID from user where USERNAME = '" + username
				+ "'";
		try {
			PreparedStatement ps = con.prepareStatement(sql);
			ResultSet rs = ps.executeQuery();
			while (rs.next()) {
				String temp=rs.getString(1);
				userid = temp;
				System.out.println(userid);

			}
		} catch (SQLException e) {
			e.printStackTrace();
		}

		String sql1 = "select BOOKCLASSID,COUNT from book where ISBN = '"
				+ isbn + "'";
		try {
			PreparedStatement ps1 = con.prepareStatement(sql1);
			ResultSet rs1 = ps1.executeQuery();
			while (rs1.next()) {
				bookclassid = String.valueOf((rs1.getObject(1)));
				System.out.println(bookclassid);
				String count1 = String.valueOf((rs1.getObject(2)));
				count = Integer.parseInt(count1);
				System.out.println("count:"+count);
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}catch(NumberFormatException ex)
		{
			ex.printStackTrace();
		}

		

		String sql2 = "update book set COUNT = " + (count + 1)
				+ " where ISBN = '" + isbn + "'";
		String sql3 = "delete from borrow where USERID= "+userid+" and BOOKCLASSID= "+bookclassid;
		try {
			PreparedStatement ps2 = con.prepareStatement(sql2);
			PreparedStatement ps3 = con.prepareStatement(sql3);
			ps2.executeUpdate(sql2);
			ps3.executeUpdate(sql3);
		} catch (SQLException e) {
			e.printStackTrace();
		}
		jdbc.closeConnection(con);

	}



	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub

		ReturnDB rdb = new ReturnDB();
		rdb.ReturnBook("9787121034985", "caohao");
	}

}