Spring Boot Web之配置接口WebMvcConfigurer

小鱼儿 2023-01-11 03:53 208阅读 0赞

# 1、前言 #

**WebMvcConfigurer**配置接口，是Spring内部的一种配置方式，采用JavaBean的形式来代替传统的xml配置文件形式进行针对框架个性化定制。基于java-based方式的Spring MVC配置，需要开发者自行创建一个配置类并**实现WebMvcConfigurer接口。**WebMvcConfigurerAdapter 抽象类是对WebMvcConfigurer接口的简单抽象（增加了一些默认实现），但在在SpringBoot2.0及Spring5.0中WebMvcConfigurerAdapter已被废弃 。

# 2、实现方式 #

官方推荐直接实现WebMvcConfigurer或者直接继承WebMvcConfigurationSupport。

##       方式一：实现WebMvcConfigurer接口【推荐使用】。 ##

##       方式二：继承WebMvcConfigurationSupport类。 ##

package org.springframework.web.servlet.config.annotation;
    
    import java.util.List;
    import org.springframework.format.FormatterRegistry;
    import org.springframework.http.converter.HttpMessageConverter;
    import org.springframework.lang.Nullable;
    import org.springframework.validation.MessageCodesResolver;
    import org.springframework.validation.Validator;
    import org.springframework.web.method.support.HandlerMethodArgumentResolver;
    import org.springframework.web.method.support.HandlerMethodReturnValueHandler;
    import org.springframework.web.servlet.HandlerExceptionResolver;
    
    public interface WebMvcConfigurer {
        default void configurePathMatch(PathMatchConfigurer configurer) {
        }
    
        default void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
        }
    
        default void configureAsyncSupport(AsyncSupportConfigurer configurer) {
        }
    
        default void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        }
    
        default void addFormatters(FormatterRegistry registry) {
        }
    
        default void addInterceptors(InterceptorRegistry registry) {
        }
    
        default void addResourceHandlers(ResourceHandlerRegistry registry) {
        }
    
        default void addCorsMappings(CorsRegistry registry) {
        }
    
        default void addViewControllers(ViewControllerRegistry registry) {
        }
    
        default void configureViewResolvers(ViewResolverRegistry registry) {
        }
    
        default void addArgumentResolvers(List<HandlerMethodArgumentResolver> resolvers) {
        }
    
        default void addReturnValueHandlers(List<HandlerMethodReturnValueHandler> handlers) {
        }
    
        default void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        }
    
        default void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
        }
    
        default void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> resolvers) {
        }
    
        default void extendHandlerExceptionResolvers(List<HandlerExceptionResolver> resolvers) {
        }
    
        @Nullable
        default Validator getValidator() {
            return null;
        }
    
        @Nullable
        default MessageCodesResolver getMessageCodesResolver() {
            return null;
        }
    }

常见举例：

/* 拦截器配置 */
    void addInterceptors(InterceptorRegistry var1);
    
    /* 视图跳转控制器 */
    void addViewControllers(ViewControllerRegistry registry);
    
    /***静态资源处理**/
    void addResourceHandlers(ResourceHandlerRegistry registry);
    
    /* 默认静态资源处理器 */
    void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer);
    
    /*** 这里配置视图解析器**/
    void configureViewResolvers(ViewResolverRegistry registry);
    
    /* 配置内容裁决的一些选项*/
    void configureContentNegotiation(ContentNegotiationConfigurer configurer);

#  3、拦截器配置举例 #

##      1）controller ##

import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    @RequestMapping("/api")
    public class HelloCtr {
    
        @GetMapping("hello")
        public String hello(String name) {
            return "hello " + name + "!";
        }
    
    }

##      2）配置拦截器 ##

import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.lang.Nullable;
    import org.springframework.stereotype.Component;
    import org.springframework.web.servlet.AsyncHandlerInterceptor;
    import org.springframework.web.servlet.ModelAndView;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    /**
     * 拦截器，打印日志
     */
    
    @Component
    public class MyInterceptor implements AsyncHandlerInterceptor {
    
        protected final Logger logger = LoggerFactory.getLogger(this.getClass());
    
        /**
         * 进入前
         */
        @Override
        public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
            String name = request.getParameter("name");
            logger.info("-------------------------before-------------------------");
            logger.info("打印参数name:" + name);
    
            return true;
        }
    
        /**
         * 执行完
         */
        @Override
        public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
                               @Nullable ModelAndView modelAndView) throws Exception {
            logger.info("-------------------------after-------------------------");
        }
    
        /**
         * 结束
         */
        @Override
        public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
                                    @Nullable Exception ex) throws Exception {
            logger.info("-------------------------Completed-------------------------");
        }
    
        /**
         * This implementation is empty.
         */
        @Override
        public void afterConcurrentHandlingStarted(HttpServletRequest request, HttpServletResponse response,
                                                   Object handler) throws Exception {
            logger.info("Concurrent");
        }
    
        protected final void error(String msg, Object... objects) {
            logger.error(msg, objects);
        }
    
        protected final void info(String msg, Object... objects) {
            logger.info(msg, objects);
        }
    }

##      3）配置WebMvcConfigurer ##

import org.springframework.context.annotation.Configuration;
    import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
    import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
    
    @Configuration
    public class MyWebMvcConfigurer implements WebMvcConfigurer {
        @Override
        public void addInterceptors(InterceptorRegistry registry) {
            registry.addInterceptor(new MyInterceptor()).addPathPatterns("/**").excludePathPatterns("/api/toLogin","/api/login","/js/**","/css/**","/images/**");
        }
    }

##      4）打印结果 ##

2021-01-25 23:14:17.459  INFO 10948 --- [nio-8080-exec-5] com.web.web.demo.config.MyInterceptor    : -------------------------before-------------------------
    2021-01-25 23:14:17.459  INFO 10948 --- [nio-8080-exec-5] com.web.web.demo.config.MyInterceptor    : 打印参数name:joe
    2021-01-25 23:14:17.461  INFO 10948 --- [nio-8080-exec-5] com.web.web.demo.config.MyInterceptor    : -------------------------after-------------------------
    2021-01-25 23:14:17.461  INFO 10948 --- [nio-8080-exec-5] com.web.web.demo.config.MyInterceptor    : -------------------------Completed-------------------------