fix

src/main/java/cn/com/qmth/examcloud/app/service/impl/CoreOeServiceImpl.java

@@ -17,10 +17,12 @@ import cn.com.qmth.examcloud.app.model.Result;
 import cn.com.qmth.examcloud.app.service.CoreOeService;
 import cn.com.qmth.examcloud.app.core.SysProperty;
 import okhttp3.FormBody;
+import okhttp3.FormBody.Builder;
 import okhttp3.MediaType;
 import okhttp3.MultipartBody;
 import okhttp3.RequestBody;
 import org.apache.commons.io.FilenameUtils;
+import org.apache.commons.lang3.StringUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -272,13 +274,16 @@ public class CoreOeServiceImpl implements CoreOeService {
     public Result getYunSignature(String key, String token, GetYunSignatureReq req) throws Exception {
         //封装请求参数
         final String requestUrl = String.format("%s/api/ecs_oe_student/examControl/yunSignature", sysProperty.getCoreOeStudentUrl());
-        RequestBody formBody = new FormBody.Builder()
+        Builder b= new FormBody.Builder()
                 .add("examRecordDataId", req.getExamRecordDataId())
                 .add("order", req.getOrder())
                 .add("fileMd5", req.getFileMd5())
-                .add("fileSuffix", req.getFileSuffix())
-                .add("ext", req.getExt())
-                .build();
+                .add("fileSuffix", req.getFileSuffix());
+        if(StringUtils.isNotBlank(req.getExt())) {
+                b.add("ext", req.getExt());
+        }
+        RequestBody formBody =b.build();
+                 
         return HttpUtils.doPost(requestUrl, formBody, key, token);
     }