下載文件java,下載文件夾安裝到手機桌面

本文目錄一覽：

• 1、Java如何利用url下載MP3保存到本地？
• 2、java下載文件會佔用cpu嗎
• 3、Java 下載文件的方法怎麼寫
• 4、求問Java文件下載的幾種方式

Java如何利用url下載MP3保存到本地？

Java如何利用url下載MP3保存的方法：

1 /** ；

2      * TODO 下載文件到本地 ；

3      * @author nadim  ；

4      * @date Sep 11, 2015 11:45:31 AM ；

5      * @param fileUrl 遠程地址 ；

6      * @param fileLocal 本地路徑 ；

7      * @throws Exception ；

8      */ ；

9     public void downloadFile(String fileUrl,String fileLocal) throws Exception {；

10         URL url = new URL(fileUrl);

11         HttpURLConnection urlCon = (HttpURLConnection) url.openConnection();

12         urlCon.setConnectTimeout(6000);

13         urlCon.setReadTimeout(6000);

14         int code = urlCon.getResponseCode();

15         if (code != HttpURLConnection.HTTP_OK) {

16             throw new Exception(“文件讀取失敗”);

17         }      

18         //讀文件流；

19        DataInputStream in = new DataInputStream(urlCon.getInputStream());

20         DataOutputStream out = new DataOutputStream(new FileOutputStream(fileLocal));

21         byte[] buffer = new byte[2048];

22         int count = 0;

23         while ((count = in.read(buffer)) 0) {；

24             out.write(buffer, 0, count);

25         }

26         out.close();

27         in.close();

28     }。

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java下載文件會佔用cpu嗎

佔用。java下載文件會佔用cpu，該Java進程佔用cpu達到92.2%，在tomcat中部署Java的web應用程序，過一段時間後出現tomcat的java進程持續佔用cpu高達100%，導致web程序訪問受阻。

Java 下載文件的方法怎麼寫

參考下面

public HttpServletResponse download(String path, HttpServletResponse response) {

try {

// path是指欲下載的文件的路徑。

File file = new File(path);

// 取得文件名。

String filename = file.getName();

// 取得文件的後綴名。

String ext = filename.substring(filename.lastIndexOf(“.”) + 1).toUpperCase();

// 以流的形式下載文件。

InputStream fis = new BufferedInputStream(new FileInputStream(path));

byte[] buffer = new byte[fis.available()];

fis.read(buffer);

fis.close();

// 清空response

response.reset();

// 設置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;

}

// 下載本地文件

public void downloadLocal(HttpServletResponse response) throws FileNotFoundException {

String fileName = “Operator.doc”.toString(); // 文件的默認保存名

// 讀到流中

InputStream inStream = new FileInputStream(“c:/Operator.doc”);// 文件的存放路徑

// 設置輸出的格式

response.reset();

response.setContentType(“bin”);

response.addHeader(“Content-Disposition”, “attachment; filename=\”” + fileName + “\””);

// 循環取出流中的數據

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();

}

}

// 下載網路文件

public void downloadNet(HttpServletResponse response) throws MalformedURLException {

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();

}

}

//支持在線打開文件的一種方式

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) { // 在線打開方式

URL u = new URL(“” + filePath);

response.setContentType(u.openConnection().getContentType());

response.setHeader(“Content-Disposition”, “inline; filename=” + f.getName());

// 文件名應該編碼成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, 0, len);

br.close();

out.close();

}

求問Java文件下載的幾種方式

InputStream fis = new BufferedInputStream(new FileInputStream(path));byte[] buffer = new byte[fis.available()];fis.read(buffer);fis.close();// 清空responseresponse.reset();// 設置response的Headerresponse.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 {// 下載本地文件String fileName = “Operator.doc”.toString(); // 文件的默認保存名// 讀到流中InputStream inStream = new FileInputStream(“c:/Operator.doc”);// 文件的存放路徑// 設置輸出的格式response.reset();response.setContentType(“bin”);response.addHeader(“Content-Disposition”, “attachment; filename=\”” + fileName + “\””);// 循環取出流中的數據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 {// 下載網路文件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();}} //支持在線打開文件的一種方式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) { // 在線打開方式URL u = new URL(“” + filePath);response.setContentType(u.openConnection().getContentType());response.setHeader(“Content-Disposition”, “inline; filename=” + f.getName());// 文件名應該編碼成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, 0, len);br.close();out.close();}