基于JSP+Servlet+JavaBean实现的图书管理系统

package com.module; import com.util.DbManage; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.List; import java.util.ArrayList; public class BookDao { public void saveBook( Book book ) { Connection conn = DbManage.getConnection(); String sql ="insert into book(name,author,press,num) values (?,?,?,?)"; try{ PreparedStatement ps = conn.prepareStatement(sql); ps.setString(1,book.getName()); ps.setString(2,book.getAuthor()); ps.setString(3,book.getPress()); ps.setInt(4,book.getNumber()); ps.executeUpdate(); ps.close(); }catch(SQLException e){ e.printStackTrace(); }finally{ DbManage.closeConnection(conn); } } public void DeleteBook( Integer id ) { Connection conn = DbManage.getConnection(); try{ System.out.println("DeleteBook in BookDao"); System.out.println( id ); String sql = "delete from book where id =?"; PreparedStatement ps = conn.prepareStatement(sql); ps.setInt(1, id); ps.executeUpdate(); }catch(SQLException e){ e.printStackTrace(); }finally{ DbManage.closeConnection(conn); } } public Book getBook( Integer id ) { Connection conn = DbManage.getConnection(); Book book = new Book(); try { String sql = "select * from book where id =?"; PreparedStatement ps = conn.prepareStatement(sql); ps.setInt(1, id); ResultSet rs = ps.executeQuery(); if(rs!=null&&rs.next()) { String name = rs.getString("name"); String author = rs.getString("author"); String press = rs.getString("press"); int num = rs.getInt("num"); book.setId(id); book.setName(name); book.setAuthor( author ); book.setPress(press); book.setNumber(num); } }catch( SQLException e) { e.printStackTrace(); } finally { DbManage.closeConnection(conn); } return book; } public List<Book> QueryBook( String name ) { List<Book> books = new ArrayList<Book>(); Connection conn = DbManage.getConnection(); String sql = "select * from book where name =?"; try{ PreparedStatement ps = conn.prepareStatement(sql); ps.setString(1,name); ResultSet rs = ps.executeQuery(); while(rs.next()){ Book book = new Book(); book.setId( rs.getInt("id")); book.setName(rs.getString("name")); book.setAuthor( rs.getString("author")); book.setPress( rs.getString("press")); book.setNumber( rs.getInt("num")); books.add(book); } rs.close(); }catch(SQLException e){ e.printStackTrace(); }finally{ DbManage.closeConnection(conn); } return books; } public boolean lendBook( Integer id,String reader_id ) { boolean b = false; Connection conn = DbManage.getConnection(); try{ String sql = "select num from book where id =?"; String sql1 = "select * from readerbooks where reader_id=? and book_id=?"; PreparedStatement ps1 = conn.prepareStatement(sql1); ps1.setString(1, reader_id); ps1.setInt(2, id); ResultSet rs1 = ps1.executeQuery(); if(!rs1.next()) { //判断是否已借过此书； PreparedStatement ps = conn.prepareStatement(sql); ps.setInt(1, id); ResultSet rs = ps.executeQuery(); if(rs.next()){ int num = rs.getInt("num"); num--; String sql2 = "update book set num=? where id=?"; PreparedStatement ps2 = conn.prepareStatement(sql2); ps2.setInt(1, num); ps2.setInt(2, id); ps2.executeUpdate(); String sql4 = "select * from book where id=?"; PreparedStatement ps4 = conn.prepareStatement(sql4); ps4.setInt(1, id); ResultSet rs4 = ps4.executeQuery(); if(rs4.next()) { String sql3 = "insert into readerbooks(reader_id,book_id,book_name,book_author," + "book_press) values(?,?,?,?,?)"; PreparedStatement ps3 = conn.prepareStatement(sql3); ps3.setString(1, reader_id); ps3.setInt(2, rs4.getInt("id")); ps3.setString(3,rs4.getString("name")); ps3.setString(4, rs4.getString("author")); ps3.setString(5, rs4.getString("press")); ps3.executeUpdate(); ps3.close(); } b = true; System.out.println("LendBook借书成功！"); ps1.close(); ps.close(); ps2.close(); } rs.close(); } }catch(SQLException e){ e.printStackTrace(); }finally{ DbManage.closeConnection(conn); } return b; } public boolean returnBook( Integer id,String reader_id ) { boolean b = false; Connection conn = DbManage.getConnection(); try{ String sql = "select num from book where id =?"; PreparedStatement ps = conn.prepareStatement(sql); ps.setInt(1, id); ResultSet rs = ps.executeQuery(); if(rs.next()){ int num = rs.getInt("num"); num++; String sql2 = "update book set num=? where id=?"; PreparedStatement ps2 = conn.prepareStatement(sql2); ps2.setInt(1, num); ps2.setInt(2, id); ps2.executeUpdate(); String sql3 = "delete from readerbooks where reader_id=? and book_id=?"; PreparedStatement ps3 = conn.prepareStatement(sql3); ps3.setString(1, reader_id); ps3.setInt(2, id); ps3.executeUpdate(); b = true; } rs.close(); }catch(SQLException e){ e.printStackTrace(); }finally{ DbManage.closeConnection(conn); } return b; } }