Java文件下载的几种方式

比眉伴天荒 2024-02-18 15:46 65阅读 0赞

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  
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;  
\}  
  
public void downloadLocal(HttpServletResponse response) throws FileNotFoundException \{  
// 下载本地文件  
String fileName = "Operator.doc".toString(); // 文件的默认保存名  
// 读到流中  
InputStream inStream = new FileInputStream("c:/Operator.doc");// 文件的存放路径  
// 设置输出的格式  
response.reset();  
response.setContentType("bin");  
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();  
\}  
\}  
  
public void downloadNet(HttpServletResponse response) throws MalformedURLException \{  
// 下载网络文件  
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, 0, byteread);  
\}  
\} catch (FileNotFoundException e) \{  
e.printStackTrace();  
\} catch (IOException e) \{  
e.printStackTrace();  
\}  
  
\}

支持在线打开的一种方式

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) \{ // 在线打开方式  
URL u = new URL("file:///" + filePath);  
response.setContentType(u.openConnection().getContentType());  
response.setHeader("Content-Disposition", "inline; filename=" + f.getName());  
// 文件名应该编码成UTF-8  
\} else \{ // 纯下载方式  
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, 0, len);  
br.close();  
out.close();  
\}