springboot的WebMvcConfigurer接口

SpringBoot 确实为我们做了很多事情， 但有时候我们想要自己定义一些Handler，Interceptor，ViewResolver，MessageConverter，该怎么做呢。在Spring Boot 1.5版本都是靠重写WebMvcConfigurerAdapter的方法来添加自定义拦截器，消息转换器等。SpringBoot 2.0 后，该类被标记为@Deprecated。因此我们只能靠实现WebMvcConfigurer接口来实现。接下来让我们来看看这个接口类吧！（列举下常用的方法供参考）

/**
 * @Author Lwh
 * @Date 2019/10/30
 * @Description 实现WebMvcConfigurer接口，
 */
@Configuration
public class WebConfig implements WebMvcConfigurer {

    /**
     * 添加类型转换器和格式化器
     * @param registry
     */
    @Override
    public void addFormatters(FormatterRegistry registry) {
        registry.addFormatterForFieldType(LocalDate.class, new USLocalDateFormatter());
    }

    /**
     * 跨域支持
     * cors协议解决跨域问题
     */
    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**")
                .allowedOrigins("*")
                .allowCredentials(true)
                .allowedMethods("GET", "POST", "DELETE", "PUT")
                .maxAge(3600 * 24);
    }

    /**
     * 添加静态资源--过滤swagger-api (开源的在线API文档)
     * @param registry
     */
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        //过滤swagger
        registry.addResourceHandler("swagger-ui.html")
                .addResourceLocations("classpath:/META-INF/resources/");

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

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

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

        //本应用
        registry.addResourceHandler("/assets/**").addResourceLocations("classpath:/assets/");

    }
    }

    /**
     * 配置消息转换器--这里我用的是alibaba 开源的 fastjson
     * @param converters
     */
    @Override
    public void configureMessageConverters(List> converters) {
        //1.需要定义一个convert转换消息的对象;
        FastJsonHttpMessageConverter fastJsonHttpMessageConverter = new FastJsonHttpMessageConverter();
        //2.添加fastJson的配置信息，比如：是否要格式化返回的json数据;
        FastJsonConfig fastJsonConfig = new FastJsonConfig();
        fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat,
                SerializerFeature.WriteMapNullValue,
                SerializerFeature.WriteNullStringAsEmpty,
                SerializerFeature.DisableCircularReferenceDetect,
                SerializerFeature.WriteNullListAsEmpty,
                SerializerFeature.WriteDateUseDateFormat);
        //3处理中文乱码问题
        List fastMediaTypes = new ArrayList<>();
        fastMediaTypes.add(MediaType.APPLICATION_JSON_UTF8);
        //4.在convert中添加配置信息.
        fastJsonHttpMessageConverter.setSupportedMediaTypes(fastMediaTypes);
        fastJsonHttpMessageConverter.setFastJsonConfig(fastJsonConfig);
        //5.将convert添加到converters当中.
        converters.add(fastJsonHttpMessageConverter);
    }
      /**
     * 配置拦截器实现api接口鉴权
     */
  @Override
    public void addInterceptors(InterceptorRegistry registry) {
       registry.addInterceptor(new RestApiInteceptor()).addPathPatterns("/api/**");
    }

}

Rest Api接口鉴权Interceptor

/**
 * Rest Api接口鉴权
 *
 * @author crm
 * @Date 2018/7/20 23:11
 */
public class RestApiInteceptor extends HandlerInterceptorAdapter {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        if (handler instanceof org.springframework.web.servlet.resource.ResourceHttpRequestHandler) {
            return true;
        }
        return check(request, response);
    }

    private boolean check(HttpServletRequest request, HttpServletResponse response) {
        if (request.getServletPath().equals(JwtConstants.AUTH_PATH)) {
            return true;
        }
        final String requestHeader = request.getHeader(JwtConstants.AUTH_HEADER);
        String authToken;
        if (requestHeader != null && requestHeader.startsWith("Bearer ")) {
            authToken = requestHeader.substring(7);

            //验证token是否过期,包含了验证jwt是否正确
            try {
                boolean flag = JwtTokenUtil.isTokenExpired(authToken);
                if (flag) {
                    RenderUtil.renderJson(response, new ErrorResponseData(BizExceptionEnum.TOKEN_EXPIRED.getCode(), BizExceptionEnum.TOKEN_EXPIRED.getMessage()));
                    return false;
                }
            } catch (JwtException e) {
                //有异常就是token解析失败
                RenderUtil.renderJson(response, new ErrorResponseData(BizExceptionEnum.TOKEN_ERROR.getCode(), BizExceptionEnum.TOKEN_ERROR.getMessage()));
                return false;
            }
        } else {
            //header没有带Bearer字段
            RenderUtil.renderJson(response, new ErrorResponseData(BizExceptionEnum.TOKEN_ERROR.getCode(), BizExceptionEnum.TOKEN_ERROR.getMessage()));
            return false;
        }
        return true;
    }

}