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文件下载 - JAVA原生

2019-11-10 20:04:54
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文件下载的几种方法。。。

下载文件的通用方法

public HttpServletResponse download(String path, HttpServletResponse response) { try { // path是指欲下载的文件的路径。 File file = new File(path); // 取得文件名。 String filename = file.getName(); // 取得文件的后缀名。 String ext = filename.substring(filename.lastIndexOf(".") + 1).toUpperCase(); // 以流的形式下载文件。 InputStream fis = new BufferedInputStream(new FileInputStream(path)); byte[] buffer = new byte[fis.available()]; fis.read(buffer); fis.close(); // 清空response response.reset(); // 设置response的Header //可保证下载的中文文件名正常 response.addHeader("Content-Disposition", "attachment;filename=" + new String(filename.getBytes(),"iso8859-1")); response.addHeader("Content-Length", "" + file.length()); OutputStream outputStream = new BufferedOutputStream(response.getOutputStream()); response.setContentType("application/octet-stream"); outputStream.write(buffer); outputStream.flush(); outputStream.close(); } catch (IOException ex) { ex.PRintStackTrace(); } return response; }

下载本地文件

public void downloadLocal(HttpServletResponse response) throws FileNotFoundException { String fileName = "sn.txt".toString(); // 文件的默认保存名 // 读到流中 InputStream inStream = new FileInputStream("D://BaiduYunDownload//sn.txt");// 文件的存放路径 // 设置输出的格式 response.reset(); response.setContentType("application/octet-stream"); response.addHeader("Content-Disposition", "attachment; filename=/"" + fileName + "/""); // 循环取出流中的数据 byte[] b = new byte[100]; int len; try { while ((len = inStream.read(b)) > 0) response.getOutputStream().write(b, 0, len); inStream.close(); } catch (IOException e) { e.printStackTrace(); } }

支持在线打开

本地测试支持:txt、PDF、jpg等

public void downLoad(String filePath, HttpServletResponse response, boolean isOnLine) throws Exception { File f = new File(filePath); if (!f.exists()) { response.sendError(404, "File not found!"); return; } BufferedInputStream br = new BufferedInputStream(new FileInputStream(f)); byte[] buf = new byte[1024]; int len = 0; response.reset(); // 非常重要 if (isOnLine) { // 在线打开方式 URL u = new URL("file:///" + filePath); response.setContentType(u.openConnection().getContentType()); response.setHeader("Content-Disposition", "inline; filename=" + URLEncoder.encode(f.getName(), "UTF-8")); // 文件名应该编码成UTF-8 } else { // 纯下载方式 response.setContentType("application/octet-stream"); response.setHeader("Content-Disposition", "attachment; filename=" + f.getName()); } OutputStream out = response.getOutputStream(); while ((len = br.read(buf)) != -1) out.write(buf, 0, len); br.close(); out.close(); }
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