Server to Server Http POST 요청 시 파라미터 처리방법 2가지와 Entity 클래스

#. 테스트 했을 때 성공한 방법

1. 일반적인 Form 파라미터 형식(?로 시작하고 &표시로 연결되는 일련의 스트링값) 전송

   - 반환 형식 json

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;

public class SimpleHttpPut { 
  public static void main(String[] args) {
    HttpClient client = new DefaultHttpClient();
    HttpPost post = new HttpPost("http://vogellac2dm.appspot.com/register");
    try {
    
 List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(1);
 nameValuePairs.add(new BasicNameValuePair("Email", "youremail"));
 nameValuePairs
          .add(new BasicNameValuePair("Passwd", "yourpassword"));
 nameValuePairs.add(new BasicNameValuePair("accountType", "GOOGLE"));
 nameValuePairs.add(new BasicNameValuePair("source",
          "Google-cURL-Example"));
 nameValuePairs.add(new BasicNameValuePair("service", "ac2dm"));

 post.setEntity(new UrlEncodedFormEntity(nameValuePairs));
   /* 반환 값 스트링 처리   
BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
      String line = "";
      while ((line = rd.readLine()) != null) {
        System.out.println(line);
      }
 */
 /** json 형태 반환값 처리 **/
 ObjectMapper mapper = new ObjectMapper();
 JsonNode node = mapper.readTree(response.getEntity().getContent());
 int resultCode = mapper.readValue(node.get("resultCode"), Integer.class); 
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
} 

※ 참조

http://www.vogella.com/articles/ApacheHttpClient/article.html

2. Json 형식({"Key":"value"}) 파라미터 전송

- 반환 형식 json

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;

import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.log4j.Logger;

public class ApacheHttpClient {
  private Logger logger = Logger.getLogger(this.getClass());
  public String restPOST(String reqUrl, String reqParam, HashMap<String, Object> extendedHeader, String contentType) {
	String serverResponse = new String();
	try {
		 
		DefaultHttpClient httpClient = new DefaultHttpClient();
		HttpPost postRequest = new HttpPost(reqUrl);
		
		/** 추가 Header 필요한 경우 설정 **/ 
		if(extendedHeader != null){
			Set<String> keySet = (Set<String>)extendedHeader.keySet();
			Iterator<String> headerKeys = keySet.iterator();
			while(headerKeys.hasNext()){
				String headerKey = headerKeys.next();
				postRequest.addHeader(headerKey, (String)extendedHeader.get(headerKey));
			}
				
		}
		/** requParam은 json 형태의 String value **/
		StringEntity input = new StringEntity(reqParam, "UTF-8");
		input.setContentType(contentType);
		postRequest.setEntity(input);

/** 또는
StringEntity entity = new StringEntity(reqParam);
entity.setContentEncoding(HTTP.UTF_8);
entity.setContentType("application/json");
httpPost.setEntity(entity);
**/
			
		HttpResponse response = httpClient.execute(postRequest);
		serverResponse = catchResponse(response);
		
		httpClient.getConnectionManager().shutdown();
	
} catch (MalformedURLException e) {
logger.error("########## ERROR IN REST POST - MalformedURLException : "+ this.getClass());
logger.error(e);
e.printStackTrace();
	    serverResponse = null;
}catch(IOException e) {;
logger.error("########## ERROR IN REST POST - IOException: "+ this.getClass());
logger.error(e);
e.printStackTrace();
serverResponse = null;
}catch(Exception e) {;
logger.error("########## ERROR IN REST POST - Exception : "+ this.getClass());
logger.error(e);
e.printStackTrace();
serverResponse = null;
}

return serverResponse;
}
private String catchResponse(HttpResponse response ) throws IOException{
	String serverResponse = "";
	if (response.getStatusLine().getStatusCode() != 200) {
		logger.error("\n########## Failed ##########\n HTTP error code : " + response.getStatusLine().getStatusCode() 
				+ "\n HTTP error reason :" + response.getStatusLine().getReasonPhrase());
		
	if(response.getStatusLine().getStatusCode() != 400)
		return new String( ("{\"error\":\""+response.getStatusLine().getStatusCode() + response.getStatusLine().getReasonPhrase() +"\"}").getBytes(), "UTF-8");
	}
 
	BufferedReader br = new BufferedReader(
                       new InputStreamReader((response.getEntity().getContent()), "UTF-8"));
 	String output;
	logger.debug("Output from Server .... \n");
		while ((output = br.readLine()) != null) {
			serverResponse += output;
			logger.debug(output);
		}
		
		return serverResponse;
	}
}

1번과 2번에서 Header값이나 파라미터 값을 담는 Entity 종류가 다르다.

1번에서 나오는 org.apache.http.client.entity.UrlEncodedFormEntity

Package org.apache.http.client.entity Additional HTTP entity implementations that depend on HttpClient specific features.

▒ 참조 http://hc.apache.org/httpcomponents-client-ga/httpclient/apidocs/org/apache/http/client/entity/package-summary.html

2번에서 나오는 org.apache.http.entity.StringEntity

Package org.apache.http.entity Common HTTP entity implementations.

▒ 참조  http://hc.apache.org/httpcomponents-core-ga/httpcore/apidocs/org/apache/http/entity/package-summary.html

글쓰기전까지 같은 패키지에 속하는 클래스일거라고 생각했는데 살짝 당황스럽다.

각 Entity 사용법에 따라 위의 두 가지 방법 말고, 다른 방법으로 POST 요청 시 파라미터를 보낼 수 있지 않을까.

보통 검색 시 나오는 Common Entity는 ByteArrayEntity, StringEntity (A self contained, repeatable entity that obtains its content from  a byte Array / a String. )는 비슷한 특성을 갖는다.

또 다른 종류의 클래스 중 FileEntity가 눈에 띈다. 파일을 어떻게 처리하는 거지?