基于Ajax与Servlet实现的图书管理系统

package Dao; import bean.Data_Info; import utils.DBUtils; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.List; public class Data_InfoDao { public List<Data_Info> findStuAll(String name){ List<Data_Info>list=null; Connection connection=null; PreparedStatement pre=null; ResultSet rs=null; try { connection = DBUtils.getConnection(); String sql = "select * from data_Info where userName=?"; pre = connection.prepareStatement(sql); pre.setString(1,name); rs = pre.executeQuery(); list = new ArrayList<>(); while(rs.next()){ String bookName = rs.getString("bookName"); String author = rs.getString("author"); String userName = rs.getString("userName"); String teacher = rs.getString("teacher"); list.add(new Data_Info(bookName,author,userName,teacher)); } } catch (SQLException throwables) { throwables.printStackTrace(); }finally { close(connection,pre,rs); } return list; } public List<Data_Info> findTeaAll(String name){ List<Data_Info>list=null; Connection connection=null; PreparedStatement pre=null; ResultSet rs=null; try { connection = DBUtils.getConnection(); String sql = "select * from data_Info where teacher=?"; pre = connection.prepareStatement(sql); pre.setString(1,name); rs = pre.executeQuery(); list = new ArrayList<>(); while(rs.next()){ String bookName = rs.getString("bookName"); String author = rs.getString("author"); String userName = rs.getString("userName"); String teacher = rs.getString("teacher"); list.add(new Data_Info(bookName,author,userName,teacher)); } } catch (SQLException throwables) { throwables.printStackTrace(); }finally { close(connection,pre,rs); } return list; } public List<Data_Info> findallScore(String name){ List<Data_Info>list=null; Connection connection=null; PreparedStatement pre=null; ResultSet rs=null; try { connection = DBUtils.getConnection(); String sql = "select * from data_Info where userName=?"; pre = connection.prepareStatement(sql); pre.setString(1,name); rs = pre.executeQuery(); list = new ArrayList<>(); while(rs.next()){ String bookName = rs.getString("bookName"); String author = rs.getString("author"); String userName = rs.getString("userName"); String teacher = rs.getString("teacher"); list.add(new Data_Info(bookName,author,userName,teacher)); } } catch (SQLException throwables) { throwables.printStackTrace(); }finally { close(connection,pre,rs); } return list; } public List<Data_Info> findall(String bookName, String userName){ List<Data_Info>list=null; Connection connection=null; PreparedStatement pre=null; ResultSet rs=null; try { connection = DBUtils.getConnection(); String sql = "select * from data_Info where bookName=? and teacher=?"; pre = connection.prepareStatement(sql); pre.setString(1,bookName); pre.setString(2,userName); rs = pre.executeQuery(); list = new ArrayList<>(); while(rs.next()){ String bookName2 = rs.getString("bookName"); String author = rs.getString("author"); String userName2 = rs.getString("userName"); String teacher = rs.getString("teacher"); list.add(new Data_Info(bookName2,author,userName2,teacher)); } } catch (SQLException throwables) { throwables.printStackTrace(); }finally { close(connection,pre,rs); } return list; } public void close(Connection connection,PreparedStatement pre,ResultSet rs){ if (connection!=null){ try { connection.close(); } catch (SQLException throwables) { throwables.printStackTrace(); } } if (pre!=null){ try { pre.close(); } catch (SQLException throwables) { throwables.printStackTrace(); } } if(rs!=null){ try { rs.close(); } catch (SQLException throwables) { throwables.printStackTrace(); } } } public boolean find(Data_Info class1){ Connection connection=null; PreparedStatement pre=null; ResultSet rs=null; boolean flag=false; try { connection = DBUtils.getConnection(); String sql = "select * from data_Info where bookName=? and userName=?"; pre = connection.prepareStatement(sql); pre.setString(1,class1.getBookName()); pre.setString(2,class1.getUserName()); rs = pre.executeQuery(); while(rs.next()){ flag=true; } } catch (SQLException throwables) { throwables.printStackTrace(); }finally { close(connection,pre,rs); } return flag; } public boolean Insert(Data_Info class1){ Connection connection=null; PreparedStatement pre=null; boolean flag = false; try { connection=DBUtils.getConnection(); String sql = "insert into data_Info (bookName,author,userName,teacher) values(?,?,?,?)"; pre = connection.prepareStatement(sql); pre.setString(1,class1.getBookName()); pre.setString(2,class1.getAuthor()); pre.setString(3,class1.getUserName()); pre.setString(4,class1.getTeacher()); flag = pre.executeUpdate()==1; } catch (SQLException throwables) { throwables.printStackTrace(); }finally { close(connection,pre,null); } return flag; } public boolean delete(Data_Info class1){ Connection connection=null; PreparedStatement pre=null; boolean flag = false; try { connection=DBUtils.getConnection(); String sql = "delete from data_Info where userName=? and bookName=?"; pre = connection.prepareStatement(sql); pre.setString(1,class1.getUserName()); pre.setString(2,class1.getBookName()); flag = pre.executeUpdate()==1; } catch (SQLException throwables) { throwables.printStackTrace(); }finally { close(connection,pre,null); } return flag; } public boolean teacherDelete(Data_Info class1){ Connection connection=null; PreparedStatement pre=null; boolean flag = false; try { connection=DBUtils.getConnection(); String sql = "delete from data_Info where bookName=? and author=? and teacher=?"; pre = connection.prepareStatement(sql); pre.setString(1,class1.getBookName()); pre.setString(2,class1.getAuthor()); pre.setString(3,class1.getTeacher());