用java写一个把mysql数据导出excel表格的代码

好的，以下是一个用Java编写的将MySQL数据导出到Excel表格的示例代码：

import java.io.FileOutputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class MySQLToExcel {

    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/mydatabase";
        String user = "root";
        String password = "mypassword";
        String query = "SELECT * FROM mytable";

        try (Connection con = DriverManager.getConnection(url, user, password);
             Statement stmt = con.createStatement();
             ResultSet rs = stmt.executeQuery(query);
             XSSFWorkbook workbook = new XSSFWorkbook();
             FileOutputStream out = new FileOutputStream("output.xlsx")) {

            // Create a new sheet in the workbook
            workbook.createSheet("Data");

            // Get the header row and add it to the sheet
            Row headerRow = workbook.getSheet("Data").createRow(0);
            int columnCount = rs.getMetaData().getColumnCount();
            for (int i = 1; i <= columnCount; i++) {
                Cell cell = headerRow.createCell(i - 1);
                cell.setCellValue(rs.getMetaData().getColumnName(i));
            }

            // Get the data rows and add them to the sheet
            int rowNum = 1;
            while (rs.next()) {
                Row dataRow = workbook.getSheet("Data").createRow(rowNum++);
                for (int i = 1; i <= columnCount; i++) {
                    Cell cell = dataRow.createCell(i - 1);
                    cell.setCellValue(rs.getString(i));
                }
            }

            // Write the workbook to the output file
            workbook.write(out);
            System.out.println("Data exported successfully!");

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

这个代码使用了 Apache POI 库来创建和写入 Excel 文件。它首先连接到 MySQL 数据库，执行查询语句，然后将结果写入 Excel 文件。你需要将 `url`、`user`、`password` 和 `query` 变量替换为你自己的值，以便它可以连接到你的数据库并执行正确的查询。