修改班级id校验

mec-education/src/main/java/com/ym/mec/education/controller/ClassGroupController.java

@@ -32,7 +32,7 @@ public class ClassGroupController {
     @PostMapping("/info")
     @ApiOperation("班级详情")
     public BaseResponse getInfo(@RequestBody ClassGroupReq classGroupReq) {
-        if (Objects.nonNull(classGroupReq.getGroupId())) {
+        if (Objects.isNull(classGroupReq.getGroupId())) {
             BaseResponse baseResponse = new BaseResponse();
             baseResponse.setReturnCode(ReturnCodeEnum.CODE_206.getCode());
             baseResponse.setMessage(ReturnCodeEnum.CODE_206.getValue());