java如何发起一次http的post请求？

@RequestMapping(value = "loginInSSO", method = RequestMethod.GET)
    public String loginInSSO(Cookyjar cookyjar, HttpServletRequest request, @Param("data")String data, HttpServletResponse response) {
        HttpUtils  client= HttpUtils.getInstance();
//        String xml = HttpUtils.beanToXml(reqsObj, ReqsObj.class);
        String xml = "";
//        String xml = "<phone>123</phone><password>123</password>";

        String md5Pwd = AlgorithmUtils.computeMD5("123");

//        String msg = client.sendHttpPost("http://117.149.16.172:20004/xct/login.htm?phone=123&password=123", xml);
        String msg = client.sendHttpPost("http://117.149.16.172:20004/xct/login.htm?phone=123&password=" + md5Pwd, xml);

        logger.info("测试msg：" + msg);
//        JSONObject jsonObject = JSONObject.fromObject(msg);
        Msg dataObj = (Msg)JSONUtils.parse(msg);

        return "redirect:" + bossIndexUrl;
    }


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package com.jianwu.xct.common;

import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.entity.mime.content.FileBody;
import org.apache.http.entity.mime.content.StringBody;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
import java.io.File;
import java.io.IOException;
import java.io.Reader;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Created by heyingchun on 2017/8/15.
 */

public class HttpUtils {

    public final static String connectionUrl="http://223.105.4.67:7100/ds/V1/api/si/siApplicationJQ";
    public final   static String key="0808E973";
    public final   static String app + bodycc);
         } catch (Exception e) {
             e.printStackTrace();
         }
    }
}