Java下載檔案的4種方式總結
阿新 • • 發佈:2021-01-12
1.以流的方式下載.
public HttpServletResponse download(String path,HttpServletResponse response) { try { // path是指欲下載的檔案的路徑。 File file = new File(path); // 取得檔名。 String filename = file.getName(); // 取得檔案的字尾名。 String ext = filename.substring(filename.lastIndexOf(".") + 1).toUpperCase(); // 以流的形式下載檔案。 InputStream fis = new BufferedInputStream(new FileInputStream(path)); byte[] buffer = new byte[fis.available()]; fis.read(buffer); fis.close(); // 清空response response.reset(); // 設定response的Header response.addHeader("Content-Disposition","attachment;filename=" + new String(filename.getBytes())); response.addHeader("Content-Length","" + file.length()); OutputStream toClient = new BufferedOutputStream(response.getOutputStream()); response.setContentType("application/octet-stream"); toClient.write(buffer); toClient.flush(); toClient.close(); } catch (IOException ex) { ex.printStackTrace(); } return response; }
2.下載本地檔案
public void downloadLocal(HttpServletResponse response) throws FileNotFoundException { // 下載本地檔案 String fileName = "Operator.doc".toString(); // 檔案的預設儲存名 // 讀到流中 InputStream inStream = new FileInputStream("c:/Operator.doc");// 檔案的存放路徑 // 設定輸出的格式 response.reset(); response.setContentType("bin"); response.addHeader("Content-Disposition","attachment; filename=\"" + fileName + "\""); // 迴圈取出流中的資料 byte[] b = new byte[100]; int len; try { while ((len = inStream.read(b)) > 0) response.getOutputStream().write(b,len); inStream.close(); } catch (IOException e) { e.printStackTrace(); } }
3.下載網路檔案
public void downloadNet(HttpServletResponse response) throws MalformedURLException { // 下載網路檔案 int bytesum = 0; int byteread = 0; URL url = new URL("windine.blogdriver.com/logo.gif"); try { URLConnection conn = url.openConnection(); InputStream inStream = conn.getInputStream(); FileOutputStream fs = new FileOutputStream("c:/abc.gif"); byte[] buffer = new byte[1204]; int length; while ((byteread = inStream.read(buffer)) != -1) { bytesum += byteread; System.out.println(bytesum); fs.write(buffer,byteread); } } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } }
4.支援線上開啟的方式
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) { // 線上開啟方式 URL u = new URL("file:///" + filePath); response.setContentType(u.openConnection().getContentType()); response.setHeader("Content-Disposition","inline; filename=" + f.getName()); // 檔名應該編碼成UTF-8 } else { // 純下載方式 response.setContentType("application/x-msdownload"); response.setHeader("Content-Disposition","attachment; filename=" + f.getName()); } OutputStream out = response.getOutputStream(); while ((len = br.read(buf)) > 0) out.write(buf,len); br.close(); out.close(); }
JAVA中批量下載檔案,將下載多個檔案打包成zip檔案下載。
//批量檔案下載(將多個檔案打包成zip包下載) public static void batchDownLoadFile(HttpServletRequest request,String filename,String[] filepath,String[] documentname,String loginname){ byte[] buffer = new byte[1024]; Date date=new Date(); //生成zip檔案存放位置 String strZipPath = Constant.exportAddress +loginname+date.getTime()+".zip"; File file=new File(Constant.exportAddress); if(!file.isDirectory() && !file.exists()){ //建立單層目錄 // f.mkdir(); // 建立多層目錄 file.mkdirs(); } try { ZipOutputStream out = new ZipOutputStream(new FileOutputStream(strZipPath)); // 需要同時下載的多個檔案 for (int i = 0; i < filepath.length; i++) { File f=new File(filepath[i]); FileInputStream fis = new FileInputStream(f); System.out.println(documentname[i]); out.putNextEntry(new ZipEntry(documentname[i])); //設定壓縮檔案內的字元編碼,不然會變成亂碼 out.setEncoding("GBK"); int len; // 讀入需要下載的檔案的內容,打包到zip檔案 while ((len = fis.read(buffer)) > 0) { out.write(buffer,len); } out.closeEntry(); fis.close(); } out.close(); PublicMethod.downLoadFile(request,response,strZipPath,filename+".zip"); File temp=new File(strZipPath); if(temp.exists()){ temp.delete(); } } catch (Exception e) { System.out.println("檔案下載錯誤"); } }
總結
到此這篇關於Java下載檔案的4種方式的文章就介紹到這了,更多相關Java下載檔案內容請搜尋我們以前的文章或繼續瀏覽下面的相關文章希望大家以後多多支援我們!