swagger return `Whitelabel Error Page` for url `../swagger-ui.html` - spring-boot

Question

I followed this link: a Chinese introduction article, according to it, I only need to add the dependencies in pom.xml. (./v2/api-docs has been always working.)
It used to work, but today it breaks.
my swagger dependencies in pom.xml file
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger2</artifactId>
<version>2.9.2</version>
</dependency>
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger-ui</artifactId>
<version>2.9.2</version>
</dependency>
I am using spring boot 2.3.3, and swagger 2.9.2 .

Answer 1

in SwaggerConfig.java,
add below codes:
#Configuration
#EnableSwagger2
public class SwaggerConfig extends WebMvcConfigurationSupport {
...
#Override
protected void addResourceHandlers(ResourceHandlerRegistry registry) {
// 解决静态资源无法访问
registry.addResourceHandler("/**")
.addResourceLocations("classpath:/static/");
// 解决swagger无法访问
registry.addResourceHandler("/swagger-ui.html")
.addResourceLocations("classpath:/META-INF/resources/");
// 解决swagger的js文件无法访问
registry.addResourceHandler("/webjars/**")
.addResourceLocations("classpath:/META-INF/resources/webjars/");
}

Answer 2

With newer versions of spring boot, this can be achieved with a property:
spring.resources.static-locations=classpath:/static/,classpath:/static/vendor/,classpath:/static/custom/
Also, make sure you configure SpringSecurity class to accept requests to this resources
#Override
public void configure(WebSecurity web)
{
web.ignoring()
.antMatchers( "/static/**","/resources/**", "/js/**", "/css/**", "/images/**");
}