swagger + spring front-end js error

There is a script error in the swagger UI loading interface, the data cannot be rendered, the problem: The interface json guarantees that content type:: application/json
spring mvc is configured as:

<mvc:message-converters register-defaults="true">
			<!-- Avoid downloading files when returning JSON when IE executes AJAX -->
			<!--@ResponseBody, etc. return encoding processing-->
			<bean class="org.springframework.http.converter.StringHttpMessageConverter">
				<constructor-arg value="UTF-8" />
				<property name="supportedMediaTypes">
					<list>
						<value>application/json;charset=UTF-8</value>
					</list>
				</property>
			</bean>
</mvc:message-converters>

If it returns a json string, the front end cannot parse it.