android中文件下载

1、在android中我门经常会用到下载网络上的某个文件。那怎么实现呢？ 如下

    public void  DownMP3(){

            String urlStr="http://192.168.18.204:8210/jxms/wechat/fileDownload?fileSign=2016-05-09_2045d8a1-d520-485d-afc0-ccf7b0b2f2f3&msgType=video"; 

         

             OutputStream output=null; 

             try { 

                 /*

                  * 通过URL取得HttpURLConnection

                  * 要网络连接成功，需在AndroidMainfest.xml中进行权限配置

                  * <uses-permission android:name="android.permission.INTERNET" />

                  */ 

                 URL url=new URL(urlStr); 

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

                 //取得inputStream，并将流中的信息写入SDCard 

                  

                 /*

                  * 写前准备

                  * 1.在AndroidMainfest.xml中进行权限配置

                  * <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

                  * 取得写入SDCard的权限

                  * 2.取得SDCard的路径： Environment.getExternalStorageDirectory()

                  * 3.检查要保存的文件上是否已经存在

                  * 4.不存在，新建文件夹，新建文件

                  * 5.将input流中的信息写入SDCard

                  * 6.关闭流

                  */ 

             

                  

                 File file=new File(pathName); 

                 InputStream input=conn.getInputStream(); 

                 if(file.exists()){ 

                  

                     return; 

                 }else{ 

                     String dir=SDCard+"/"+path; 

                     new File(dir).mkdir();//新建文件夹 

                  

                   

                     file.createNewFile();//新建文件 

                     output=new FileOutputStream(file); 

                     //读取大文件 

                     byte[] buffer=new byte[4*1024]; 

                     while(input.read(buffer)!=-1){ 

                         output.write(buffer); 

                     } 

                     output.flush(); 

                 } 

             } catch (MalformedURLException e) { 

                 e.printStackTrace(); 

             } catch (IOException e) { 

                 e.printStackTrace(); 

             }finally{ 

                 try { 

                  if(output!=null){

                      output.close(); 

                  }

                

                     } catch (IOException e) {  

                         e.printStackTrace(); 

                     } 

             } 

         } 

文件下载的类封装好了，剩下的就是 调用了。。。