import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.ParseException;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.EntityUtils;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * Created by  dbz on 2016/4/5.
 */
public class HttpClientUtil {
    /**
     *
     * @param url 請求的地址
     * @param params 請求引數為Map<String,String>,最終會把map裡的引數以&拼接起來
     * @return
     */
    public static String post(String url,Map<String,String> params){
        //建立HttpClient物件
        HttpClient client=new DefaultHttpClient();
        //建立httpPost物件並封裝請求引數物件
        HttpPost post=postForm(url,params);
        String result=null;
        //呼叫傳送請求方法
        result=invoke(client,post);
        //當HttpClient的例項不再需要時，可以使用連線管理器關閉
        client.getConnectionManager().shutdown();
        return result;
    }
    public static String get(String url,Map<String,String> params){
        DefaultHttpClient client=new DefaultHttpClient();
        String result=null;
        HttpGet get=new HttpGet(url);
        result=invoke(client,get);
        client.getConnectionManager().shutdown();
        return result;
    }
    public static HttpPost postForm(String url,Map<String,String> params){
        HttpPost httpPost=new HttpPost(url);
        List<NameValuePair> nvps=new ArrayList<NameValuePair>();
        for(String key:params.keySet()){
            nvps.add(new BasicNameValuePair(key,params.get(key)));
        }
        try {
            httpPost.setEntity(new UrlEncodedFormEntity(nvps, HTTP.UTF_8));
        }catch (UnsupportedEncodingException e){
            e.printStackTrace();
        }
        return httpPost;
    }
    public static String invoke(HttpClient client,HttpUriRequest request){
        HttpResponse response=sendRequest(client,request);
        String result=parseResponse(response);
        return result;
    }
    public static HttpResponse sendRequest(HttpClient client,HttpUriRequest request){
        HttpResponse response=null;
        try{
            response=client.execute(request);
        }catch (ClientProtocolException cpe){
            cpe.printStackTrace();
        }catch (IOException ioe){
            ioe.printStackTrace();
        }
        return response;
    }
    public static String parseResponse(HttpResponse response){
        HttpEntity entity=response.getEntity();
        String charset= EntityUtils.getContentCharSet(entity);
        String result=null;
        try{
            result=EntityUtils.toString(entity);
        }catch (ParseException pe){
            pe.printStackTrace();
        }catch (IOException ioe){
            ioe.printStackTrace();
        }
        return result;
    }
}