java后台调用接口并获取返回值

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.StatusLine;
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.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;
import org.springframework.data.repository.query.QueryMethod;
import com.alibaba.fastjson.JSON;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.flatform.fklc.domain.FkLogin;
import java.io.IOException;
public class EntityZDUtil {
//连接的网址，这里假装一个
private static final String SERVICE_URL = "http://192.122.91.111:8080/test/tester/tttest.do";


//方法
public static String Test() {
CloseableHttpClient httpClient = HttpClients.createDefault();
try {
HttpPost httpPost = new HttpPost(SERVICE_URL);
List nvps = new ArrayList();
//根据需要传输的参数建立实体FkLogin

//需要的数据格式为
 data={
"uname": "admin",
"upwd": "12345"
}
                        FkLogin fkLogin = new FkLogin();
fkLogin.setUname("admin");
fkLogin.setUpwd("12345");
//将实体（List之类的也行）转化为Json传过去
nvps.add(new BasicNameValuePair("data", JSON.toJSONString(fkLogin)));
httpPost.setEntity(new UrlEncodedFormEntity(nvps, "UTF-8"));
CloseableHttpResponse response = httpClient.execute(httpPost);
try {
StatusLine statusLine = response.getStatusLine();
int statusCode = statusLine.getStatusCode();
                                //200为请求成功（只是请求成功，如进行查询，连上了，查询失败也是200，具体成功与否看返回的数据）

if (statusCode == 200) {
                                       //获取返回值

HttpEntity entity = response.getEntity();
String mes = EntityUtils.toString(entity, "UTF-8");
return mes;
} else {
return null;
}
} catch (Exception e) {
e.printStackTrace();
} finally {
response.close();
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}