update

mec-biz/src/main/java/com/ym/mec/biz/dal/dto/ImGroupDto.java

@@ -4,11 +4,12 @@ import com.ym.mec.biz.dal.entity.ImGroup;
 import com.ym.mec.common.entity.BaseEntity;
 import io.swagger.annotations.ApiModelProperty;
 
+import java.util.ArrayList;
 import java.util.List;
 
 public class ImGroupDto extends BaseEntity {
     @ApiModelProperty(value = "用户列表")
-    private List<String> userIdList;
+    private List<String> userIdList = new ArrayList<>();
 
     @ApiModelProperty(value = "群名称")
     private String groupName;