java网络编程URLConnection和HttpClient（下载图片范例）

最新推荐文章于 2025-02-27 16:25:18 发布

雅阁驸马

最新推荐文章于 2025-02-27 16:25:18 发布

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分类专栏： java资源文章标签： android开发

本文链接：https://blog.youkuaiyun.com/u011833422/article/details/34430913

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本文介绍了使用Android平台上的HttpClient和URLConnection两种方式来下载图片的方法，并对比了它们的实现细节。通过具体的代码示例，展示了如何处理下载过程中的进度显示等问题。

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一、用HttpClient下图片：

 protected Bitmap doInBackground(String... params) {
               //  完成对图片下载的功能
               Bitmap bitmap=null;
               ByteArrayOutputStream outputStream=new ByteArrayOutputStream();
               InputStream inputStream=null;
               try {
                    HttpClient httpClient=new DefaultHttpClient();
                    HttpGet httpGet=new HttpGet(params[0]);
                    HttpResponse httpResponse=httpClient.execute(httpGet);
                    if(httpResponse.getStatusLine().getStatusCode()==200){
                          inputStream=httpResponse.getEntity().getContent();
                          //先要获得文件的总长度
                          long file_length=httpResponse.getEntity().getContentLength();
                          int len=0;
                          byte[] data=new byte[1024];//读取
                          int total_length=0;
                          while((len=inputStream.read(data))!=-1){
                        	  System.out.println(total_length);
                                total_length += len;
                                
                                int value=(int) ((total_length / (float) file_length) * 100);
                                publishProgress(value);//把刻度发布出去
                                outputStream.write(data, 0, len);//写入
                          }
                          byte[] result=outputStream.toByteArray();//声明字节数组
                          bitmap=BitmapFactory.decodeByteArray(result, 0, result. length);
                    }
               } catch (Exception e) {
                    // TODO: handle exception
                    e.printStackTrace();
               }finally{
                    if(inputStream!=null){
                          try {
                                inputStream.close();
                          } catch (IOException e) {
                                e.printStackTrace();                       
                          }
                    }
               }
               return bitmap;
         }

二、用URLConnection下载图片

public void run (){
				 URL urll;
					try {
						urll = new URL("http://www.91ri.org/9408.html");
						HttpURLConnection conn =  (HttpURLConnection) urll.openConnection();     
				        conn.setConnectTimeout(5000);     
				         //获取到文件的大小       
				            
				        int total_length = conn.getContentLength();
				        
				        //pd.setMax(conn.getContentLength());
				        
				         InputStream is = conn.getInputStream();     
				         File file = new File(Environment.getExternalStorageDirectory(), "aupdata.html");     
				        FileOutputStream fos = new FileOutputStream(file);     
				         BufferedInputStream bis = new BufferedInputStream(is);     
				         byte[] buffer = new byte[1024];     
				         int len ;     
				        int total=0;  
				        while((len = bis.read(buffer)) != -1){
				        	fos.write(buffer, 0, len);
				        	total = total + len ;
				        	System.out.println(total);
				        	
				        	Thread.sleep(1000);
				        	
				        	progress_num = (100*total)/total_length ;
				        	System.out.println("pro" + progress_num + "gg" + total_length);
				        	//progress_num = total;
				        	progress_handler.sendEmptyMessage(0x123);
				        	//pd.setProgress(total);
				        }
				        
				         
				           fos.close();     
				           bis.close();     
				           is.close();

二者的比较，请看以下链接

http://blog.youkuaiyun.com/zealot_2002/article/details/8250268