# 主体识别示例
本章节对主体识别AK/SK方式使用SDK进行示例说明。
- 主体识别示例代码只需将AK/SK信息替换为实际AK/SK，代码中可以使用ImageMainObjectDetectionReq中的withUrl或withImage方法配置图像信息（image和url参数二选一），示例中以url为例，配置完成后运行即可。
- endpoint是华为云各服务应用区域和各服务的终端节点，详情请查看[地区和终端节点](https://developer.huaweicloud.com/endpoint?Image) 。
1. 主体识别调用示例代码如下：
   ```
   package com.huaweicloud.sdk.test;
    
   import com.huaweicloud.sdk.core.auth.ICredential;
   import com.huaweicloud.sdk.core.auth.BasicCredentials;
   import com.huaweicloud.sdk.core.exception.ConnectionException;
   import com.huaweicloud.sdk.core.exception.RequestTimeoutException;
   import com.huaweicloud.sdk.core.exception.ServiceResponseException;
   import com.huaweicloud.sdk.image.v2.region.ImageRegion;
   import com.huaweicloud.sdk.image.v2.*;
   import com.huaweicloud.sdk.image.v2.model.*;
    
   public class RunImageMainObjectDetectionSolution {
    
       public static void main(String[] args) {
          // 认证用的ak和sk硬编码到代码中或者明文存储都有很大的安全风险，建议在配置文件或者环境变量中密文存放，使用时解密，确保安全
          // 本示例以ak和sk保存在环境变量中来实现身份验证为例，运行本示例前请先在本地环境中设置环境变量HUAWEICLOUD_SDK_AK和HUAWEICLOUD_SDK_SK
           String ak = System.getenv("HUAWEICLOUD_SDK_AK");
           String sk = System.getenv("HUAWEICLOUD_SDK_SK");
    
           ICredential auth = new BasicCredentials()
                   .withAk(ak)
                   .withSk(sk);
    
           ImageClient client = ImageClient.newBuilder()
                   .withCredential(auth)
                   .withRegion(ImageRegion.valueOf("cn-north-4"))  //此处替换为您开通服务的区域，详情请查看地区和终端节点.
                   .build();
           RunImageMainObjectDetectionRequest request = new RunImageMainObjectDetectionRequest();
           ImageMainObjectDetectionReq body = new ImageMainObjectDetectionReq();
           body.withThreshold(30f);
           body.withUrl("https://XXX.jpg");    //替换为公网可以访问的图片地址
           request.withBody(body);
           try {
               RunImageMainObjectDetectionResponse response = client.runImageMainObjectDetection(request);
               System.out.println(response.toString());
           } catch (ConnectionException e) {
               e.printStackTrace();
           } catch (RequestTimeoutException e) {
               e.printStackTrace();
           } catch (ServiceResponseException e) {
               e.printStackTrace();
               System.out.println(e.getHttpStatusCode());
               System.out.println(e.getErrorCode());
               System.out.println(e.getErrorMsg());
           }
       }
   }
   ```
   
2. 执行示例代码文件，控制台输出主体识别结果即表示程序执行成功。相关参数说明请参考[主体识别API](https://support.huaweicloud.com/api-image/image_03_0042.html#section4)。
   ```
   RunImageMainObjectDetectionResponse {
       result: [class ImageMainObjectDetectionInstance {
           label: bounding_box
           location: {height=327.77, top_left_x=3.7, top_left_y=1.72, width=463.03}
           confidence: 95.73
       }, class ImageMainObjectDetectionInstance {
           label: main_object_box
           location: {height=328.35, top_left_x=3.22, top_left_y=1.5, width=456.63}
           confidence: 88.35
       }]
   }
   ```