问题

集成knife4j后，无法访问api文档。

解决方案

拦截器配置文件里配置不拦截静态资源

因为swagger的页面都属于静态资源，需要在拦截器里排除掉。

package com.minglei.hotnews.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;

@Configuration
public class WebAppConfig extends WebMvcConfigurationSupport {
   
    @Autowired
    LoginInterceptor loginInterceptor;
    //实现拦截器 要拦截的路径以及不拦截的路径
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
   

        //注册自定义拦截器，添加拦截路径和排除拦截路径
        registry.addInterceptor(loginInterceptor).addPathPatterns("/**").excludePathPatterns("/doc.html").excludePathPatterns("/webjars/**");
    }

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
   
        //配置拦截器访问静态资源
        registry.addResourceHandler("doc.html").addResourceLocations("classpath:/META-INF/resources/");
        registry.addResourceHandler("/favicon.ico").addResourceLocations("classpath:/META-INF/resources/");
        registry.addResourceHandler("/webjars/**").addResourceLocations("classpath:/META-INF/resources/webjars/");
    }
}

登录拦截器详细配置

package com.minglei.hotnews.config;

import com.minglei.hotnews.Utils.*;
import io.jsonwebtoken.Claims;
import org.springframework.lang.Nullable;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;
import java.lang.reflect.Method;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

@Component
public class LoginInterceptor implements HandlerInterceptor {
   
    //方法执行前
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
   

        //判断前端是否传来token如果没传进行拦截
        String token=request.getHeader("token");//从http请求头中获取token

        System.out.println("handler:"+handler);

        if(!(handler instanceof HandlerMethod)){
   
            return true;
        }

        HandlerMethod handlerMethod=(HandlerMethod)handler;

        PassToken handlePass = handlerMethod.getBean().getClass().getDeclaredAnnotation(PassToken.class);
        System.out.println("拿到的handlePass“"+handlePass);
        System.out.println("handle拿到的类是："+handlerMethod.getBean().getClass().getName());
        System.out.println("handle拿到的类是否是swagger的控制器类："+handlerMethod.getBean().getClass().getName().equals("springfox.documentation.swagger.web.ApiResourceController"));

        //判断如果请求的类是swagger的控制器，直接通行。
        if(handlerMethod.getBean().getClass().getName().equals("springfox.documentation.swagger.web.ApiResourceController")){
   
            return  true;
        }

        if(null != handlePass){
   
            System.out.println("类上带PassToken注解，直接通行");
           return true;
        }else {
   
            Method method=handlerMethod.getMethod();
            //检查是否有@passtoken注解，有则跳过验证
            if(method.isAnnotationPresent(PassToken.class))
            {
   
                PassToken passToken=method.getAnnotation(PassToken.class);
                if(passToken.required())
                {
   
                    //方法带passToken直接通行
                    System.out.println("方法带passToken直接通行");
                    return  true;
                }else {
   
                    System.out.println("方法没有带passToken，进行token验证");
                    //判断token是否过期
                    if(token!=null)
                    {
   
                        Claims claims = JWTUtil.parseJWT(token);
                        //解析token判断是否过期
                        if(claims!=null) {
   
                            long expTime = Long.parseLong(claims.get("ExpTime").toString());
                            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                            Date nowDate = new Date();
                            Date expDate = new Date(expTime);
                            String nowDateStr = sdf.format(nowDate);
                            String expDateStr=sdf.format(expDate);
                            if (nowDate.getTime() >= expDate.getTime()) {
   
                                response.setContentType("json/html; charset=utf-8");
                                //response.sendError(HttpServletResponse.SC_FORBIDDEN,"用户无权限,请登录");
                                PrintWriter printWriter = response.getWriter();
                                Map<String, String> resultError = new HashMap<>();
                                resultError.put("code", "403");
                                resultError.put("message", "Token已过期，请重新登录");
                                Object ces = JsonUtil.objectToString(resultError);
                                printWriter.write(ces.toString());
                                return false;
                            }
                            else
                            {
   
                                //把当前登录信息保存到threadLocal
                                LocalThreadRelUserInfo localThreadRelUserInfo=new LocalThreadRelUserInfo();
                                localThreadRelUserInfo.setUserId(Long.parseLong(claims.get("UserId").toString()));
                                localThreadRelUserInfo.setUserName(claims.get("UserName").toString());
                                LocalThreadRelUser.set(localThreadRelUserInfo);
                            }
                        }
                        else
                        {
   
                            response.setContentType("json/html; charset=utf-8");
                            //response.sendError(HttpServletResponse.SC_FORBIDDEN,"用户无权限,请登录");
                            PrintWriter printWriter = response.getWriter();
                            Map<String, String> resultError = new HashMap<>();
                            resultError.put("code", "403");
                            resultError.put("message", "Token已过期，请重新登录");
                            Object ces = JsonUtil.objectToString(resultError);
                            printWriter.write(ces.toString());
                            return false;
                        }
                    }else {
   
                        //提示无权限访问
                        response.setContentType("json/html; charset=utf-8");
                        //response.sendError(HttpServletResponse.SC_FORBIDDEN,"用户无权限,请登录");
                        PrintWriter printWriter=response.getWriter();
                        Map<String,String> resultError=new HashMap<>();
                        resultError.put("code","403");
                        resultError.put("message","用户无权限访问,请登录");
                        Object ces = JsonUtil.objectToString(resultError);
                        printWriter.write(ces.toString());
                        return false;
                    }
                }
            }else {
   
                System.out.println("方法没有带passToken，进行token验证");
                //判断token是否过期
                if(token!=null)
                {
   
                    Claims claims = JWTUtil.parseJWT(token);
                    //解析token判断是否过期
                    if(claims!=null) {
   
                        long expTime = Long.parseLong(claims.get("ExpTime").toString());
                        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                        Date nowDate = new Date();
                        Date expDate = new Date(expTime);
                        String nowDateStr = sdf.format(nowDate);
                        String expDateStr=sdf.format(expDate);
                        if (nowDate.getTime() >= expDate.getTime()) {
   
                            response.setContentType("json/html; charset=utf-8");
                            //response.sendError(HttpServletResponse.SC_FORBIDDEN,"用户无权限,请登录");
                            PrintWriter printWriter = response.getWriter();
                            Map<String, String> resultError = new HashMap<>();
                            resultError.put("code", "403");
                            resultError.put("message", "Token已过期，请重新登录");
                            Object ces = JsonUtil.objectToString(resultError);
                            printWriter.write(ces.toString());
                            return false;
                        }
                        else
                        {
   
                            //把当前登录信息保存到threadLocal
                            LocalThreadRelUserInfo localThreadRelUserInfo=new LocalThreadRelUserInfo();
                            localThreadRelUserInfo.setUserId(Long.parseLong(claims.get("UserId").toString()));
                            localThreadRelUserInfo.setUserName(claims.get("UserName").toString());
                            LocalThreadRelUser.set(localThreadRelUserInfo);
                        }
                    }
                    else
                    {
   
                        response.setContentType("json/html; charset=utf-8");
                        //response.sendError(HttpServletResponse.SC_FORBIDDEN,"用户无权限,请登录");
                        PrintWriter printWriter = response.getWriter();
                        Map<String, String> resultError = new HashMap<>();
                        resultError.put("code", "403");
                        resultError.put("message", "Token已过期，请重新登录");
                        Object ces = JsonUtil.objectToString(resultError);
                        printWriter.write(ces.toString());
                        return false;
                    }
                }else {
   
                    //提示无权限访问
                    response.setContentType("json/html; charset=utf-8");
                    //response.sendError(HttpServletResponse.SC_FORBIDDEN,"用户无权限,请登录");
                    PrintWriter printWriter=response.getWriter();
                    Map<String,String> resultError=new HashMap<>();
                    resultError.put("code","403");
                    resultError.put("message","用户无权限访问,请登录");
                    Object ces = JsonUtil.objectToString(resultError);
                    printWriter.write(ces.toString());
                    return false;
                }
            }
        }
        return true;// 只有返回true才会继续向下执行，返回false取消当前请求
    }

    //方法执行结束后
    @Override
     public   void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
                         @Nullable Exception ex) throws Exception {
   
        //清楚掉线程保存的用户信息
        LocalThreadRelUser.remove();
    }
}

除此之外可能还有别的原因

需要结合你自己的业务来判断是那种原因造成的。
knife官方文档针对此错误的说明：https://doc.xiaominfo.com/faq/knife4j-exception.html