專案中需要請求第三方介面，而且要求請求引數資料為json型別的。本來首先使用的是httpclient的jar包，但是因為專案中已經使用了common-httpclient的jar包，引起了衝突，所以不得不使用common-httpclient來實現。

import java.io.BufferedReader;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL
 
;
import java.net.URLConnection;
import java.util.List;
import java.util.Map;
import java.util.zip.GZIPInputStream;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpMethod;
import org.apache.commons.httpclient.NameValuePair;
import org.apache.commons.httpclient
 
.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.methods.RequestEntity;
import org.apache.commons.httpclient.methods.StringRequestEntity;
import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


public class HTTPUtils {

    private static Logger logger = LoggerFactory.getLogger
 
(HTTPUtils.class);

    /**
     * post請求
     * @param url
     * @param json
     * @return
     */
    public static String postJosnContent(String url, String Json) throws Exception {
//      HttpPost method = new HttpPost(url);  
//      DefaultHttpClient httpClient = new DefaultHttpClient();  
//      String ret = null;
//      try {
//           StringEntity entity = new StringEntity(Json,"UTF-8");//解決中文亂碼問題     
//             entity.setContentEncoding("UTF-8");    
//             entity.setContentType("application/json");
//             method.setEntity(entity);    
//             HttpResponse result = httpClient.execute(method);  
//             ret = EntityUtils.toString(result.getEntity());  
//      } catch (Exception e) {
//          throw e;
//      } finally {
//          method.releaseConnection();
//      }
//      return ret;
        logger.error("請求介面引數：" + Json);
        PostMethod method = new PostMethod(url);
        HttpClient httpClient = new HttpClient();
        try {
            RequestEntity entity = new StringRequestEntity(Json,"application/json","UTF-8");
            method.setRequestEntity(entity);
            httpClient.executeMethod(method);
            logger.error("請求介面路徑url：" + method.getURI().toString());
            InputStream in = method.getResponseBodyAsStream();
            //下面將stream轉換為String
            StringBuffer sb = new StringBuffer();
            InputStreamReader isr = new InputStreamReader(in, "UTF-8");
            char[] b = new char[4096];
            for(int n; (n = isr.read(b)) != -1;) {
                sb.append(new String(b, 0, n));
            }
            String returnStr = sb.toString();
            return returnStr;
        } catch (Exception e) {
            e.printStackTrace();
            throw e;
        } finally {
            method.releaseConnection();
        }
    }
}