JAVA 实现文件下载

// 1. 设置响应头（Excel文件示例）
response.setContentType("application/vnd.ms-excel;charset=UTF-8");
String fileName = "example.xlsx"; // 替换为实际文件名
String contentDisposition = "attachment;filename=" + java.net.URLEncoder.encode(fileName, "UTF-8");
response.setHeader("Content-Disposition", contentDisposition);
response.setCharacterEncoding("UTF-8");

// 2. 获取输出流并写入数据
try (ServletOutputStream out = response.getOutputStream()) {
    byte[] data = getYourData(); // 替换为你的数据获取逻辑（byte[]/InputStream等）
    out.write(data);
    out.flush();
} catch (IOException e) {
    // 处理异常
    response.reset(); // 清除可能已写入的响应
    response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
    response.getWriter().write("下载失败: " + e.getMessage());
}