Java文件下载的几种方式

本文内容纲要：

Java文件下载的几种方式

publicHttpServletResponsedownload(Stringpath,HttpServletResponseresponse){

try{

//path是指欲下载的文件的路径。

Filefile=newFile(path);

//取得文件名。

Stringfilename=file.getName();

//取得文件的后缀名。

Stringext=filename.substring(filename.lastIndexOf(".")+1).toUpperCase();

//以流的形式下载文件。

InputStreamfis=newBufferedInputStream(newFileInputStream(path));

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

fis.read(buffer);

fis.close();

//清空response

response.reset();

//设置response的Header

response.addHeader("Content-Disposition","attachment;filename="+newString(filename.getBytes()));

response.addHeader("Content-Length",""+file.length());

OutputStreamtoClient=newBufferedOutputStream(response.getOutputStream());

response.setContentType("application/octet-stream");

toClient.write(buffer);

toClient.flush();

toClient.close();

}catch(IOExceptionex){

ex.printStackTrace();

}

returnresponse;

}

publicvoiddownloadLocal(HttpServletResponseresponse)throwsFileNotFoundException{

//下载本地文件

StringfileName="Operator.doc".toString();//文件的默认保存名

//读到流中

InputStreaminStream=newFileInputStream("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=newbyte[100];

intlen;

try{

while((len=inStream.read(b))>0)

response.getOutputStream().write(b,0,len);

inStream.close();

}catch(IOExceptione){

e.printStackTrace();

}

}

publicvoiddownloadNet(HttpServletResponseresponse)throwsMalformedURLException{

//下载网络文件

intbytesum=0;

intbyteread=0;

URLurl=newURL("windine.blogdriver.com/logo.gif");

try{

URLConnectionconn=url.openConnection();

InputStreaminStream=conn.getInputStream();

FileOutputStreamfs=newFileOutputStream("c:/abc.gif");

byte[]buffer=newbyte[1204];

intlength;

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

bytesum+=byteread;

System.out.println(bytesum);

fs.write(buffer,0,byteread);

}

}catch(FileNotFoundExceptione){

e.printStackTrace();

}catch(IOExceptione){

e.printStackTrace();

}

}

//支持在线打开文件的一种方式

publicvoiddownLoad(StringfilePath,HttpServletResponseresponse,booleanisOnLine)throwsException{

Filef=newFile(filePath);

if(!f.exists()){

response.sendError(404,"Filenotfound!");

return;

}

BufferedInputStreambr=newBufferedInputStream(newFileInputStream(f));

byte[]buf=newbyte[1024];

intlen=0;

response.reset();//非常重要

if(isOnLine){//在线打开方式

URLu=newURL("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());

}

OutputStreamout=response.getOutputStream();

while((len=br.read(buf))>0)

out.write(buf,0,len);

br.close();

out.close();

}

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原文链接：https://www.cnblogs.com/ungshow/archive/2009/01/12/1374491.html