JDBC------之结果集元数据的操作02

package com.itheima.hui;

import com.itheima.hui.beans.User;
import com.itheima.hui.utils.JDBCUtils;
import jdk.internal.org.objectweb.asm.tree.FieldInsnNode;

import java.io.IOException;
import java.lang.reflect.Field;
import java.sql.*;

public class JDBCormIgnore {
    public static void main(String[] args) {
        String sql = "select user_id userId, user_name userName,user_birthday userBirthday, user_gender userGender from user where user_id=?";
        Object o = JDBCormIgnore.ignoreMatch(sql, 1);
        System.out.println(o);


    }

    public static Object ignoreMatch(String sql, Object... args) {


        Connection connect = null;
        PreparedStatement preparedStatement = null;
        ResultSet resultSet = null;
        //1.使用自定义工具类获得连接对象
        try {
            connect = JDBCUtils.getConnect();
            preparedStatement = connect.prepareStatement(sql);
            //占位符赋值操作
            for (int i = 0; i < args.length; i++) {
                preparedStatement.setObject(i + 1, args[i]);
            }
            //执行获得结果集
            resultSet = preparedStatement.executeQuery();
            //根据结果集对象获得结果数据源
            ResultSetMetaData metaData = resultSet.getMetaData();
            int columnCount = metaData.getColumnCount();//查询结果的列数

            //获取一个查询对象
            if (resultSet.next()) {
                //创建User对象
                User user = new User();
                for (int i = 0; i < columnCount; i++) {
                    //获取列的别名，如果没有别名的话就获取真实的列名
                    String columnLabel = metaData.getColumnLabel(i + 1);
                    Class<User> clazz = User.class;
                    Object value = resultSet.getObject(i + 1);
                    Field declaredField = clazz.getDeclaredField(columnLabel);
                    declaredField.setAccessible(true);
                    declaredField.set(user, value);


                }


                return user;

            }


        } catch (Exception e) {
            e.printStackTrace();
        } finally {
//使用自定义工具类关闭资源

            JDBCUtils.close(connect, preparedStatement, resultSet);


        }

        return null;
    }


}