我正在尝试使用Java将MySql数据导出到文件中，但是我无法获取表头

Question

我能够将mysql导出到csv文件，但是我没有获取表头，我希望将文件保存到系统时显示头。

这是我正在使用的Java代码：

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

public class ExportData {

    public static void main(String args[]) {
        String Driver;
        Statement stmt;
        Driver = "com.mysql.jdbc.Driver";
        Connection con = null;

        try {
            Class.forName(Driver);
            con = DriverManager.getConnection(
                  "jdbc:mysql://localhost/emp", "root", "");
            if (!con.isClosed()) {
                System.out.println("Successfully connected to MySQL DataBase \n");
                stmt = con.createStatement();
                String filename = "C:/2.txt";
                String tablename = "employees";
                String sql;
                stmt.executeUpdate("SELECT * INTO OUTFILE \""
                        + filename + "\" FROM " + tablename);
            }
        } catch (Exception e) {
            System.err.println("Exception: " + e.getMessage());
        } finally {
            try {
                if (con != null) {
                    con.close();
                }
            } catch (SQLException e) {
            }
        }
    }
}

Answer 1

您需要使用ResultSetMetaData

Answer 2

这是作为相关MySQL手册页的注释附带的示例：

select 'idPago','fecha','lead','idAlumno','idTipoPago','idGpo',
    'idTaller','idDocente','pagoImporte','NoFactura','facturaImporte',
    'mes','formaPago','observaciones' union all
(select id_control_pagos, fecha, lead, id_alumno, id_concepto_pago, id_Gpo,id_Taller,
    id_docente, Pagoimporte, NoFactura, FacturaImporte, Mensualidad_No, FormaPago,
    Observaciones from control_pagos
    into outfile 'c:\\data.csv'
    FIELDS TERMINATED BY ','
    OPTIONALLY ENCLOSED BY '"'
    LINES TERMINATED BY '\n');

简而言之，您必须手动添加列标签。

Answer 3

您不能将executeUpdate()用于选择查询.....请使用executeQuery()