import jakarta.servlet.ServletOutputStream; import jakarta.servlet.http.HttpServletResponse; import lombok.SneakyThrows;  import java.io.FileInputStream; import java.net.URLEncoder; import java.nio.charset.StandardCharsets;  /**  * 功能描述  *  * @author jason  */ public class DownloadUtil {      /**      * 下载文件      *      * @param response      * @param filePath     文件路径      * @param originalName 文件原名      */     @SneakyThrows     public static void start(HttpServletResponse response, String filePath, String originalName) {         // 读到流中         FileInputStream inputStream = new FileInputStream(filePath);// 文件的存放路径         response.reset();         response.setContentType("application/octet-stream");         response.addHeader("Content-Disposition", "attachment; filename=" + URLEncoder.encode(originalName, StandardCharsets.UTF_8));         ServletOutputStream outputStream = response.getOutputStream();         int len;         byte[] cache = new byte[1024];         // 从输入流中读取一定数量的字节，并将其存储在缓冲区字节数组中，读到末尾返回-1         while ((len = inputStream.read(cache)) > 0) {             outputStream.write(cache, 0, len);             outputStream.flush();         }         inputStream.close();         outputStream.close();     }  }