servlet实现登录和注册

package cn.frame.dao; import cn.frame.domin.User; import cn.frame.util.JDBCUtils; import java.sql.*; public class UserDao { public static void insert(User user) throws SQLException { Connection connection = null; PreparedStatement statement = null; try { connection = JDBCUtils.getConnection(); //创建预编译的Statement String sql="insert into rgister values(?,?,?,?,?)"; statement = connection.prepareStatement(sql); //设置参数 statement.setString(1,user.getUsername()); statement.setString(2,user.getPassword()); statement.setString(3,user.getEmail()); statement.setString(4,user.getName()); statement.setString(5,user.getTel()); statement.executeUpdate(); } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); }finally { statement.close(); connection.close(); } } public boolean select(String username2,String password2) throws SQLException { Connection connection=null; Statement statement=null; String username1; String password1; String sql="select username,password from rgister"; try { ResultSet rs = null; connection = JDBCUtils.getConnection(); statement= connection.createStatement(); rs=statement.executeQuery(sql); while (rs.next()) { username1 = rs.getString("username"); password1 = rs.getString("password"); if (username1.equals(username2) && password1.equals(password2)) { return true; } } } catch (SQLException e) { e.printStackTrace(); } catch (ClassNotFoundException e) { e.printStackTrace(); } finally { statement.close(); connection.close(); } return false; } }