项目启动报错（如图）：
org.springframework.context.ApplicationContextException: Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException

三 · 解决方案（着急可略过1 直接看 2 ）

1、网上大概有几种：

（1）swagger版本问题，升级3.0版本（亲测对我项目无用）

（2）拦截器自定义各种写法，各种路径放开（个人感觉越看越迷)

（3）properties文件的更改（亲测对我项目无用）

2、我的方案，摒弃杂念从根本入手

Springboot1.5 继承?WebMvcConfigurerAdapter的写法，Springboot2.7版本升级已经不支持了，如图：

经查找资料理清有两种方式可实现自定义拦截器：

（1）继承??mvc的配置类??WebMvcConfigurationSupport?

a、springboot2.0以后，mvc配置类从 WebMvcConfigurerAdapter 变成了??WebMvcConfigurationSupport，因此写法如下：

b、?需格外注意的是，在springboot2.0.0之后继承WebMvcConfigurationSupport类，要重写addInterceptors 和 addResourceHandlers 方法，以及配置好静态资源路径? ，尤其是swagger-ui.html，不然会导致404，当然也不要忘记根据需要写跨域方法：

?c、跨域的? allowedOriguns("*") 也变成了 allowedOriginPatterns("*")：

?至此，项目正常启动，一切正常了，第一种方法结束；

（2）实现?WebMvcConfigurer? 接口

a、实现?WebMvcConfigurer接口，一定要加上@EnableWebMvc 注解，告诉spring 我要完全自己控制mvc配置，也就是说所有配置自己重写，所有默认配置都没了；有博主说到这样写，有时会导致很多请求进不来，或者参数转换出错之类的，因为spring mvc默认的转换器已经不生效了,包括全局配置的Jackson也会失效；也不排除这种可能。

（该博主的博文参考：https://blog.csdn.net/weixin_43831204/article/details/110322060?utm_medium=distribute.pc_relevant.none-task-blog-2~default~baidujs_baidulandingword~default-1-110322060-blog-94445071.pc_relevant_downloadblacklistv1&spm=1001.2101.3001.4242.2&utm_relevant_index=4）

当然，目前我没有遇到，因为我重写的方法路径该放开的放开，该拦截的拦截了。

如果此处不加@EnableWebMvc 注解会报文章开始的错误，导致项目运行不起来！！

b、加好@EnableWebMvc注解后，也不再需要重写的方法了，因为会报红报错，所以注释或删掉?super.addInterceptors(registry); 、super.addResourceHandlers(registry);? 并且同样要写好放开静态资源路径的代码，如图：

?至此，方法二启动成功，项目一切正常了。

四 · 完整代码

继承??mvc的配置类??WebMvcConfigurationSupport?的完整代码：

package cn.cinfotech.common.config;


import cn.cinfotech.filter.LoginInterceptor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.*;

import javax.annotation.Resource;


/**
 * @author fantong
 * Springmvc 拦截器注册
 */
@Configuration
//@EnableWebMvc
//public class InterceptorConfig extends WebMvcConfigurerAdapter {
public class InterceptorConfig extends WebMvcConfigurationSupport {

//public class InterceptorConfig implements WebMvcConfigurer {
//    @Autowired
    @Resource
    private LoginInterceptor loginInterceptor;
    @Override
    public void addInterceptors(InterceptorRegistry registry) {

        //注册拦截器

//        registry.addInterceptor(new AuthorizationInterceptor()).excludePathPatterns("/**");
        registry.addInterceptor(loginInterceptor)                       
                .addPathPatterns("/**")                                
                .excludePathPatterns("/user/XXXXXX/XXXXXX","/XXXXXX/XXXXXX","/user/XXXXXX/XXXXXX","/XXXXXX/v2/alipay_callback", "/XXXXXX/iosPay","/error","/XXXXXX/v2/wxCallBack","/XXXXXX/v2/XXXXXX","/swagger-resources/**","/webjars/**","/static/**","/swagger-ui.html/**");//"/qrcode/v2/pc/inquireLoginState",
//                .excludePathPatterns(String.valueOf(excludePath));
        //在springboot2.0.0之后继承WebMvcConfigurationSupport类，重写addInterceptors方法
        //     *
       super.addInterceptors(registry);
    }

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {

        registry.addResourceHandler("/**")
                .addResourceLocations("classpath:/static/")
                .addResourceLocations("classpath:/resources/");
        registry.addResourceHandler("/templates/**").addResourceLocations("classpath:/templates/");

        registry.addResourceHandler("swagger-ui.html","doc.html").addResourceLocations("classpath:/META-INF/resources/");
        //Windows下
        registry.addResourceHandler("/uploads2/**").addResourceLocations("file:D:/springbootFile/upload/images/");
        //Mac或Linux下(没有CDEF盘符)
        registry.addResourceHandler("/uploads/**").addResourceLocations("file:/home/qmake/workspace/images/userImg/");
        super.addResourceHandlers(registry);


    }


    /**
     * 跨域支持
     * @author QianChi
     * @date 2021/6/30 9:55
     *
     */
    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**")
//                .allowedOrigins("*")
                .allowedOriginPatterns("*")
                .allowCredentials(true)
                .allowedMethods("GET", "POST", "DELETE", "PUT", "PATCH", "OPTIONS", "HEAD")
                .maxAge(3600 * 24);
    }
}

?实现WebMvcConfigurer?接口的完成拦截器代码：

package cn.cinfotech.common.config;


import cn.cinfotech.filter.LoginInterceptor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.*;

import javax.annotation.Resource;


/**
 * @author fantong
 * Springmvc 拦截器注册
 */
@Configuration
@EnableWebMvc
//public class InterceptorConfig extends WebMvcConfigurerAdapter {
//public class InterceptorConfig extends WebMvcConfigurationSupport {

public class InterceptorConfig implements WebMvcConfigurer {
//    @Autowired
    @Resource
    private LoginInterceptor loginInterceptor;
    @Override
    public void addInterceptors(InterceptorRegistry registry) {

        //注册拦截器

//        registry.addInterceptor(new AuthorizationInterceptor()).excludePathPatterns("/**");
        registry.addInterceptor(loginInterceptor)                       
                .addPathPatterns("/**")                                
                .excludePathPatterns("/user/XXXXXX/XXXXXX","/XXXXXX/XXXXXX","/user/XXXXXX/XXXXXX","/XXXXXX/v2/alipay_callback", "/XXXXXX/iosPay","/error","/XXXXXX/v2/wxCallBack","/XXXXXX/v2/XXXXXX","/swagger-resources/**","/webjars/**","/static/**","/swagger-ui.html/**");//"/qrcode/v2/pc/inquireLoginState",
//                .excludePathPatterns(String.valueOf(excludePath));
        //在springboot2.0.0之后继承WebMvcConfigurationSupport类，重写addInterceptors方法
        //     *
//        super.addInterceptors(registry);
    }

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {

        registry.addResourceHandler("/**")
                .addResourceLocations("classpath:/static/")
                .addResourceLocations("classpath:/resources/");
        registry.addResourceHandler("/templates/**").addResourceLocations("classpath:/templates/");

        registry.addResourceHandler("swagger-ui.html","doc.html").addResourceLocations("classpath:/META-INF/resources/");
        //Windows下
        registry.addResourceHandler("/uploads2/**").addResourceLocations("file:D:/springbootFile/upload/images/");
        //Mac或Linux下(没有CDEF盘符)
        registry.addResourceHandler("/uploads/**").addResourceLocations("file:/home/qmake/workspace/images/userImg/");
//        super.addResourceHandlers(registry);


    }


    /**
     * 跨域支持
     * @author QianChi
     * @date 2021/6/30 9:55
     *
     */
    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**")
//                .allowedOrigins("*")
                .allowedOriginPatterns("*")
                .allowCredentials(true)
                .allowedMethods("GET", "POST", "DELETE", "PUT", "PATCH", "OPTIONS", "HEAD")
                .maxAge(3600 * 24);
    }
}

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