String getParamJavadoc(JavadocProvider javadocProvider, MethodParameter methodParameter) {
		String pName = methodParameter.getParameterName();
		DelegatingMethodParameter delegatingMethodParameter = (DelegatingMethodParameter) methodParameter;
		if (!delegatingMethodParameter.isParameterObject()) {
			return javadocProvider.getParamJavadoc(methodParameter.getMethod(), pName);
		}
		String fieldName;
		if (StringUtils.isNotEmpty(pName) && pName.contains(DOT))
			fieldName = StringUtils.substringAfterLast(pName, DOT);
		else fieldName = pName;

		String paramJavadocDescription = null;
		Class cls = ((DelegatingMethodParameter) methodParameter).getExecutable().getDeclaringClass();
		if (cls.getSuperclass() != null && cls.isRecord()) {
			Map<String, String> recordParamMap = javadocProvider.getRecordClassParamJavadoc(cls);
			if (recordParamMap.containsKey(fieldName)) {
				paramJavadocDescription = recordParamMap.get(fieldName);
			}
		}

		Field field = FieldUtils.getDeclaredField(cls, fieldName, true);
		String fieldJavadoc = javadocProvider.getFieldJavadoc(field);
		if (StringUtils.isNotBlank(fieldJavadoc)) {
			paramJavadocDescription = fieldJavadoc;
		}
		return paramJavadocDescription;
	}
Gets param javadoc.

@param javadocProvider the javadoc provider
@param methodParameter the method parameter
@return the param javadoc
springdoc-openapi-starter-common/src/main/java/org/springdoc/core/service/GenericParameterService.java