[Java]how to use the gzipped http response by using the apache http-client ver.3.x

how to use the gzipped http response by using the apache http-client ver.3.x

• References
  
  • apache http-client 3.x home
  • example to use gzipped response in http client-4.x
    
• Example
  

  //set url
  String url="http://hc.apache.org/httpclient-3.x/";
  
  //initialize apache HttpClient object and HttpMethod
  HttpClient httpClient = new HttpClient();
  HttpMethod httpMethod = new GetMethod(url);
  //set followRedirects function to true if you need.
  httpMethod.setFollowRedirects(true);
  //set Accept-Encoding request header
  httpMethod.setRequestHeader("Accept-Encoding","gzip");
  
  try{
   //access to the url and get response status
   int status = httpClient.executeMethod(http_method);
  
   //check response status. if the value of response status is set to 200, get body stream
   if(status == 200){
    //check the response header "Content-Encoding". the value of Content-Encoding header contains the
    //"gzip" value, this means the response stream is gzipped.
    Header contentEncodingHeader=httpMethod.getResponseHeader("Content-Encoding");
    String contentEncoding = contentEncodingHeader!=null ? contentEncodingHeader.getValue() : "";
    String contentEncodingLowerCase=contentEncoding.toLowerCase();
    boolean isGzipped=(contentEncodingLowerCase.indexOf("gzip")>=0);
    
    //get response stream
    InputStream stream=httpMethod.getResponseBodyAsStream();
    
    InputStream bodyStream=null;
    ByteArrayOutputStream outStream=null;
    try{
     //if the response stream is gzipped,  derived stream is converted into the GZIPInputStream.
     //the response stream is not gzipped, set the stream without conversion
     bodyStream = isGzipped ? new GZIPInputStream(stream) : stream;
     
     //change the response from InputStream to Byte Array.
     outStream=new ByteArrayOutputStream();
     byte[] buffer = new byte[4096];
     int length;
     while((length=bodyStream.read(buffer))>0){
      outStream.write(buffer,0,length);
     }
     
     //get the response charset.
     String charset=httpMethod.getResponseCharSet();
     //convert the response byte array to the String object.
     String body=new String(outStream.toByteArray(),charset);
  
     //Instead of converting the InputStream to Byte array,
     //we can convert the inputstream to String by using the InputStreamReader and BufferedReader directly.
     //But we can't read the responsed InputStream twice.
     //for example.
     //InputStreamReader bodyReader=new InputStreamReader(bodyStream,charset);
     //BufferedReader bodyBufferedReader=new BufferedReader(bodyReader);
     //String line=bodyBufferedReader.readLine();
     //while(line!=null){
     // bodyBuffer.append(line);
     // line=bodyBufferedReader.readLine();
     //}
     //String body=bodyBuffer.toString();
    }catch(Exception e1){
     throw e1;
    }finally{
     //close ByteArrayOutputStream
     if(outStream!=null){
      try{
       outStream.close();
      }catch(Exception ignore){}
     }
     
     //close InputStream
     if(bodyStream!=null){
      try{
       bodyStream.close();
      }catch(Exception ignore){}
     }
     if(stream!=null){
      try{
       stream.close();
      }catch(Exception ignore){}
     }
    }
   }
  }catch(Exception e0){
   System.out.println("Error, "+e0);
  }finally{
   httpMethod.releaseConnection();
  }