JavaWeb图书管理系统

package daoImp; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.List; import dao.BookDao; import db.DBCon; import entity.Book; public class BookDaoImp implements BookDao { Connection cn; PreparedStatement psm=null; private ResultSet rs; @Override public boolean add(Book book) { // TODO Auto-generated method stub boolean flag=false; DBCon dbcon=new DBCon(); cn=dbcon.getConnection(); String sql="insert into books(name,price,num,type) values(?,?,?,?)"; try { psm=cn.prepareStatement(sql); psm.setString(1, book.getName()); psm.setString(2, book.getPrice()); psm.setString(3, book.getNum()); psm.setString(4, book.getType()); psm.executeUpdate(); flag=true; cn.close(); psm.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return flag; } @Override public boolean delete(String name) { // TODO Auto-generated method stub boolean flag=false; DBCon dbcon=new DBCon(); cn=dbcon.getConnection(); String sql="delete from books where name=?"; try { psm=cn.prepareStatement(sql); psm.setString(1, name); if(psm.executeUpdate()!=0) { flag=true; } cn.close(); psm.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return flag; } @Override public boolean update(Book book) { // TODO Auto-generated method stub boolean flag=false; DBCon dbcon=new DBCon(); cn=dbcon.getConnection(); String sql="update books set price=?,num=?,type=? where name=?"; try { psm=cn.prepareStatement(sql); psm.setString(1, book.getPrice()); psm.setString(2, book.getNum()); psm.setString(3, book.getType()); psm.setString(4, book.getName()); if(psm.executeUpdate()!=0) { flag=true; } cn.close(); psm.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return flag; } @Override public Book SearchByName(String name) { // TODO Auto-generated method stub DBCon dbcon=new DBCon(); cn=dbcon.getConnection(); Book book=new Book(); String sql="select * from books where name=?"; try { psm=cn.prepareStatement(sql); psm.setString(1, name); rs=psm.executeQuery(); if(rs.next()) { String bookname=rs.getString(2); String price=rs.getString(3); String num=rs.getString(4); String type=rs.getString(5); book.setName(bookname); book.setPrice(price); book.setNum(num); book.setType(type); } cn.close(); psm.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return book; } @Override public List<Book> traversal() { // TODO Auto-generated method stub DBCon dbcon=new DBCon(); cn=dbcon.getConnection(); List<Book> listBook=new ArrayList<Book>(); String sql="select * from books"; try { psm=cn.prepareStatement(sql); rs=psm.executeQuery(); //判断数据库中是否查询到图书 if(rs.next()) { //再次将rs指针置0 rs.absolute(0); //遍历rs指针，将图书信息存入listBook列表 while(rs.next()) { Book book=new Book(); book.setId(rs.getString(1)); book.setName(rs.getString(2)); book.setPrice(rs.getString(3)); book.setNum(rs.getString(4)); book.setType(rs.getString(5)); listBook.add(book); } } cn.close(); psm.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return listBook; } } /*CSDNqq_42197887*/