java文件下載,java文件下載中文文件名亂碼

本文目錄一覽：

• 1、java文件下載401
• 2、Java文件下載怎麼實現的
• 3、Java 下載文件的方法怎麼寫

java文件下載401

報錯。java文件下載401，是產生報錯了。Java文件是由SunMicrosystems公司，於1995年5月推出的Java程序設計語言和Java平台的總稱。

Java文件下載怎麼實現的

下載就很簡單了

把你要下載的文件做成超級鏈接，可以不用任何組件

比如說

下載一個word文檔

a href=”名稱.doc”名稱.doc/a

路徑你自己寫

import java.io.File;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.InputStream;

import java.io.RandomAccessFile;

import java.net.HttpURLConnection;

import java.net.ProtocolException;

import java.net.URI;

import java.net.URL;

import java.util.Random;

/**

*

* 實現了下載的功能*/

public class SimpleTh {

public static void main(String[] args){

// TODO Auto-generated method stub

//String path = “倩女幽魂.mp3”;//MP3下載的地址

String path =””;

try {

new SimpleTh().download(path, 3); //對象調用下載的方法

} catch (Exception e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

public static String getFilename(String path){//獲得文件的名字

return path.substring(path.lastIndexOf(‘/’)+1);

}

public void download(String path,int threadsize) throws Exception//下載的方法

{//參數 下載地址，線程數量

URL url = new URL(path);

HttpURLConnection conn = (HttpURLConnection)url.openConnection();//獲取HttpURLConnection對象

conn.setRequestMethod(“GET”);//設置請求格式，這裡是GET格式

conn.setReadTimeout(5*1000);//

int filelength = conn.getContentLength();//獲取要下載文件的長度

String filename = getFilename(path);

File saveFile = new File(filename);

RandomAccessFile accessFile = new RandomAccessFile(saveFile, “rwd”);

accessFile.setLength(filelength);

accessFile.close();

int block = filelength%threadsize ==0?filelength/threadsize:filelength/threadsize+1;

for(int threadid = 0;threadid=threadsize;threadid++){

new DownloadThread(url,saveFile,block,threadid).start();

}

}

private final class DownloadThread extends Thread{

private URL url;

private File saveFile;

private int block;//每條線程下載的長度

private int threadid;//線程id

public DownloadThread(URL url,File saveFile,int block,int threadid){

this.url = url;

this.saveFile= saveFile;

this.block = block;

this.threadid = threadid;

}

@Override

public void run() {

//計算開始位置的公式：線程id*每條線程下載的數據長度=？

//計算結束位置的公式：（線程id+1）*每條線程下載數據長度-1=？

int startposition = threadid*block;

int endposition = (threadid+1)*block-1;

try {

try {

RandomAccessFile accessFile = new RandomAccessFile(saveFile, “rwd”);

accessFile.seek(startposition);//設置從什麼位置寫入數據

HttpURLConnection conn = (HttpURLConnection)url.openConnection();

conn.setRequestMethod(“GET”);

conn.setReadTimeout(5*1000);

conn.setRequestProperty(“Range”,”bytes= “+startposition+”-“+endposition);

InputStream inStream = conn.getInputStream();

byte[]buffer = new byte[1024];

int len = 0;

while((len = inStream.read(buffer))!=-1){

accessFile.write(buffer, 0, len);

}

inStream.close();

accessFile.close();

System.out.println(“線程id：”+threadid+”下載完成”);

} catch (FileNotFoundException e) {

e.printStackTrace();

}

} catch (IOException e) {

e.printStackTrace();

}

}

}

}

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();

}

}

// 下載網絡文件

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();

}