牛人，牛人，快来瞅瞅：android下载文件保存文件的问题

Question

我的问题是：想从网上下载pdf文件并保存到sdcard中，但现在问题是，我所保存的pdf文件好像不是正规格式的pdf文件，以至于手机上装了几个pdf阅读器都无法打开，电脑adobe软件也无法打开，但是手机用PoQoP-Document软件可以打开
     我判断是我的pdf文件生成的有问题，可能非正规pdf格式，但我得到数据流后该如何生成呢？下面是我的代码，还请高手看看，非常感谢！
                File dirFile=new File(path_info);
                if(!dirFile.exists()){
                        dirFile.mkdir();
                        Log.v("whether make", ""+dirFile.exists());
                }
                String pdf_name=urlPdf.substring(urlPdf.lastIndexOf("/")+1);
                
                File pdf_File=new File(dirFile, pdf_name);
                if(!pdf_File.exists()){
                        try {
                                pdf_File.createNewFile();
                        } catch (IOException e) {
                                e.printStackTrace();
                        }
                }
                try {
                        FileOutputStream fos=new FileOutputStream(pdf_File);
                        try {
                                URL myUrl=new URL(urlPdf);
                                try {
                                        URLConnection conn=myUrl.openConnection();
                                        HttpURLConnection httpConn=(HttpURLConnection)conn;
                                        httpConn.connect();
                                        
                                        if (httpConn.getResponseCode() == HttpURLConnection.HTTP_OK) {
                                                int contentLength = httpConn.getContentLength();
                                                InputStream is=httpConn.getInputStream();
                                                if (is == null) throw new RuntimeException("stream is null");                                                                                                                                                
                                                BufferedInputStream reader=null;
                                                BufferedOutputStream out=null;
                                                reader=new BufferedInputStream(is, 1024);
                                                out=new BufferedOutputStream(fos , 1024);
                                                byte[] bytes=new byte[512];
                                                int length=0;
                                                while((length=reader.read(bytes))!=-1){
                                                        out.write(bytes, 0, length);
                                                }
                                                fos.flush();
                                                is.close();
                                                fos.close();
                                                
                                                openPDF(path_info+"/"+pdf_name);
                                                progressD.dismiss();                                        }
                                } catch (IOException e) {
                                        e.printStackTrace();
                                }
                        } catch (MalformedURLException e) {
                                e.printStackTrace();
                        }
                } catch (FileNotFoundException e) {
                        e.printStackTrace();
                }
        

Answer 1

 if (httpConn.getResponseCode() == HttpURLConnection.HTTP_OK) {
  int contentLength = httpConn.getContentLength();
  InputStream is=httpConn.getInputStream();
  if (is == null) throw new RuntimeException("stream is null");    
  byte[] bytes=new byte[1024];
  int length=0;
  ByteArrayOutputStream baos=new ByteArrayOutputStream();
   while((len=is.read(data))!=-1)
baos.write(data, 0, len);
  fos.write(baos.toByteArray());
  fos.flush();
  is.close();
  fos.close();
    
  openPDF(path_info+"/"+pdf_name);
  progressD.dismiss();  }
  } catch (IOException e) {
  e.printStackTrace();
  }
  } catch (MalformedURLException e) {
  e.printStackTrace();
  }
  } catch (FileNotFoundException e) {
  e.printStackTrace();
  }
试试 这个！！！

Answer 2

   对流整体读写看成不成
if (is == null) throw new RuntimeException("stream is null");   int len = is.available();
   BufferedInputStream reader=null;
   BufferedOutputStream out=null;
   reader=new BufferedInputStream(is, len);
   out=new BufferedOutputStream(fos , len);
   byte[] bytes=new byte[len];
   int length=0;
   while((length=reader.read(bytes))!=-1){
   out.write(bytes, 0, length);
   }
   fos.flush();

Answer 3

你设断点跟一下你的代码。一般我都这样： byte[] buffer = new byte[1024];
int lenght = 0;
while ((lenght = inputStream.read(buffer)) > 0){
fos.write(buffer, 0, lenght);
}

Answer 4

inputStream 为 InputStream
fos 为 FileOutputStream

Answer 5

去掉这句话试下  fos.flush();
此方法不保证能将这些字节实际写入到物理设备（如磁盘驱动器）