java返回excel文件流

在Java中，可以使用Apache POI库来生成Excel文件并返回其内容作为字节流。 Apache POI是一个开源的Java库，可以读写Microsoft Office格式的文档。

首先，您需要下载Apache POI库并将其引入您的项目。 然后，您可以使用以下代码示例来生成一个简单的Excel文件：

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
public class ExcelGenerator {
    public static byte[] generateExcelFile() throws IOException {
        try (XSSFWorkbook workbook = new XSSFWorkbook(); ByteArrayOutputStream out = new ByteArrayOutputStream();) {
            XSSFSheet sheet = workbook.createSheet("Sheet1");
            Object[][] data = {
                    {"Name", "Age", "Gender"},
                    {"John", 25, "Male"},
                    {"Jane", 30, "Female"},
                    {"Jim", 35, "Male"}
            int rowNum = 0;
            for (Object[] datatype : data) {
                Row row = sheet.createRow(rowNum++);
                int colNum = 0;
                for (Object field : datatype) {
                    Cell cell = row.createCell(colNum++);
                    if (field instanceof String) {
                        cell.setCellValue((String) field);
                    } else if (field instanceof Integer) {
                        cell.setCellValue((Integer) field);
            workbook.write(out);
            return out.toByteArray();
最后，您可以使用以下代码将生成的Excel文件流返回给客户端：
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ExcelDownloadServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        byte[] excelContent = ExcelGenerator.generateExcelFile();
        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
        response.setHeader("Content-Disposition", "attachment; filename=example.xlsx");
        response.setContentLength(excelContent.length);
        try (ServletOutputStream out = response.getOutputStream();) {
            out.write(excelContent);