简要：

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本文简要介绍使用Apache HttpClient工具调用旷世科技的Face API。

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前期准备：

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依赖包maven地址：

<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient -->

<dependency>

	<groupId>org.apache.httpcomponents</groupId>

	<artifactId>httpclient</artifactId>

	<version>4.5.4</version>

</dependency>

api_key、api_secret的获取，可以登录旷世科技官网注册获取免费的key和secret。

Detect API说明文档

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java 测试代码：

package buct.edu.cn;

import java.net.URI;

import org.apache.http.HttpEntity;

import org.apache.http.HttpResponse;

import org.apache.http.client.HttpClient;

import org.apache.http.client.methods.HttpPost;

import org.apache.http.client.utils.URIBuilder;

import org.apache.http.entity.StringEntity;

import org.apache.http.impl.client.HttpClients;

import org.apache.http.util.EntityUtils;

public class HttpClientDemo {

	public static void main(String[] args) {

		HttpClient httpclient = HttpClients.createDefault();

		//设置请求参数

		String api_key = "<api_key>";

		String api_secret = "<api_secret>";

		String image_url = "http://gb.cri.cn/mmsource/images/2013/02/19/27/12679377093283173211.jpg";

		String return_attributes = "gender,age";

        try

        {

            URIBuilder builder = new URIBuilder("https://api-cn.faceplusplus.com/facepp/v3/detect");

            URI uri = builder.build();

            HttpPost request = new HttpPost(uri);  

            StringEntity reqEntity = new StringEntity("api_key="+api_key+"&api_secret="+api_secret+"&image_url="+image_url+"&return_attributes="+return_attributes+"");

            reqEntity.setContentType("application/x-www-form-urlencoded");

            request.setEntity(reqEntity);

            HttpResponse response = httpclient.execute(request);

            HttpEntity entity = response.getEntity();

            if (entity != null)

            {

                System.out.println(EntityUtils.toString(entity));

            }

        }

        catch (Exception e)

        {

            System.out.println(e.getMessage());

        }

	}

}

测试结果：

{"image_id": "qVohAsm0QmanSo9LBNtUcQ==", "request_id": "1514360502,7fc98900-59ca-4ac1-bbf0-95d5ada7588f", "time_used": 308, "faces": [{"attributes": {"gender": {"value": "Female"}, "age": {"value": 25}}, "face_rectangle": {"width": 173, "top": 160, "left": 215, "height": 173}, "face_token": "949f896eca7e645f27afc080971479f5"}]}

注意：

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免费版key的QPS(每秒钟支持的调用次数):10，但是这个在后台是与其他用户共享的，所以经常会出现：

{"error_message":"CONCURRENCY_LIMIT_EXCEEDED"}

这个是操过了QPS限制所致，也可以理解，毕竟是免费的产品。

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