Jdbc读取Blob数据

有个问题，就是要知道具体是第几个字段是blob类型。若是对象，批量处理的时候并不容易兼容blob

package jdbc;

import org.junit.Test;

import java.io.*;
import java.sql.*;

/**
 * @author 小邱
 * @version 0.0.1
 * @description PreparedStatement操作Blob类型数据(图片视频等数据)
 * @since 2021/9/28 16:27
 */
public class PreparedStatementBlobTest {

    //查询Blob数据
    @Test
    public void test2() throws SQLException, IOException {

        Connection connection = JdbcUtils.getConnection();
        String sql = "select username,photo from customers where username = ? ";
        PreparedStatement ps = connection.prepareStatement(sql);
        ps.setObject(1,"小明");
        ResultSet rs = ps.executeQuery();
        if (rs.next()) {
            System.out.println(rs.getString(1));
            Blob photo = rs.getBlob(2);
            InputStream photoBinaryStream = photo.getBinaryStream();
            FileOutputStream outputStream = new FileOutputStream(new File("abd.jpg"));
            byte[] bytes = new byte[1024];
            int len;
            while ((len=photoBinaryStream.read(bytes))!=-1){
                outputStream.write(bytes,0,len);
            }

        }
        JdbcUtils.close(connection,ps,rs);
    }
}