1.使用的版本

Swagger版本：2.9.2

Spring Boot版本：2.6.15

2.问题

（1）控制台报错

o.s.web.servlet.PageNotFound - No mapping for GET /swagger-ui.html

WARN  o.s.web.servlet.PageNotFound - No mapping for GET /swagger-ui.html

（2）页面报错

This application has no explicit mapping for /error, so you are seeing this as a fallback.

3.问题原因

实现了WebMvcConfigurer接口，重写了addResourceHandlers方法

package com.sdses.config;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class MyWebMVCConfig implements WebMvcConfigurer {

    @Value("${digital.file.resource-path}")
    private String resourcePath;

    @Value("${digital.file.base-file-path}")
    private String locationPath;

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        //匹配到resourceHandler,将URL映射至本地文件夹
        registry.addResourceHandler(resourcePath).addResourceLocations("file:///" + locationPath);
    }
}

4.解决

  经过分析发现由于项目中有配置类（@Configuration）继承了WebMvcConfigurer类 ，重写了addResourceHandlers()方法，导致默认的Swagger静态资源被覆盖，而缺失了配置。需要重新指定静态资源。

可在该继承配置类中，显式添加如下swagger静态资源：

配置Swagger UI和WebJars资源的访问路径

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        //匹配到resourceHandler,将URL映射至本地文件夹
        registry.addResourceHandler(resourcePath).addResourceLocations("file:///" + locationPath);

        // 配置Swagger UI和WebJars资源的访问路径，使得这些静态资源可以通过特定的URL路径在Web应用中被访问
        registry.addResourceHandler("doc.html")
                .addResourceLocations("classpath:/META-INF/resources/");

        registry.addResourceHandler("swagger-ui.html")
                .addResourceLocations("classpath:/META-INF/resources/");
        registry.addResourceHandler("/webjars/**")
                .addResourceLocations("classpath:/META-INF/resources/webjars/");

    }
}