Java InputStream读取网络响应Response数据的方法!(重要)

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Java InputStream读取数据问题

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原理讲解 

1. 关于InputStream.read()
     在从数据流里读取数据时，为图简单，经常用InputStream.read()方法。这个方法是从流里每次只读取读取一个字节，效率会非常低。     更好的方法是用InputStream.read(byte[] b)或者InputStream.read(byte[] b,int off,int len)方法，一次读取多个字节。
 

      如果这样写代码：

int count = in.available();  
  byte[] b = new byte[count];  
  in.read(b);

int count = 0;  
 while (count == 0) {  
  //count = in.available();  
  
  count=response.getEntity().getContentLength();//(HttpResponse response)  
 }  
 byte[] b = new byte[count];  
 in.read(b); 

  byte[] bytes = new byte[count];  
  int readCount = 0; // 已经成功读取的字节的个数  
  while (readCount < count) {  
   readCount += in.read(bytes, readCount, count - readCount);  
  }  

用这段代码可以保证读取count个字节，除非中途遇到IO异常或者到了数据流的结尾(EOFException).

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代码分享

下面分享我自己写的测试代码片段，供大家参考:

    /** 
         * <b>获取指定的URL返回的数据信息</b> 
         * @param <font color="#efac10"><a href="http://www.baidu.com">_url:指定的URL</a></font> 
         * @return 
         * @throws ClientProtocolException 
         * @throws IOException 
         */  
        public String getReponse(String _url) throws ClientProtocolException, IOException  
        {  
            String readContent=null;  
            DefaultHttpClient httpclient = new DefaultHttpClient();  
            HttpGet httpget = new HttpGet(SinaJsonTest.SinaUrl);  
            System.out.println("0.Send the URL to Sina Sever....");  
            HttpResponse response = httpclient.execute(httpget);  
            HttpEntity entity = response.getEntity();  
      
            System.out.println("1.Get Response Status: " + response.getStatusLine());  
            if (entity != null) {  
                System.out.println("  Get ResponseContentEncoding():"+entity.getContentEncoding());  
                System.out.println("  Content Length():"+entity.getContentLength());  
                //getResponse  
                InputStream in=entity.getContent();  
                int count = 0;  
                while (count == 0) {  
                 count = Integer.parseInt(""+entity.getContentLength());//in.available();  
                }  
                byte[] bytes = new byte[count];  
                int readCount = 0; // 已经成功读取的字节的个数  
                while (readCount <= count) {  
                 if(readCount == count)break;  
                 readCount += in.read(bytes, readCount, count - readCount);  
                }  
                  
                //转换成字符串  
                readContent= new String(bytes, 0, readCount, "UTF-8"); // convert to string using bytes  
      
                System.out.println("2.Get Response Content():\n"+readContent);  
            }  
            return readContent;  
        }  

Java InputStream读取网络响应Response数据的方法!(重要)

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原文地址：http://www.cnblogs.com/lonelyxmas/p/4638346.html