SpringBoot--对SpirngMVC的自动配置

最新推荐文章于 2025-02-18 16:12:18 发布

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最新推荐文章于 2025-02-18 16:12:18 发布

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原文链接：http://www.cnblogs.com/AshOfTime/p/10902379.html

Spring Boot对Spring MVC提供了诸多自动配置，涵盖视图解析器、静态资源、转换器与格式化器、HttpMessageConverters等方面。如视图解析器包含ContentNegotiatingViewResolver等，可添加自定义解析器；转换器负责数据类型转换，添加自定义的只需放入容器；自定义HttpMessageConverters放入容器会被添加到Spring MVC中。

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SpringBoot对SpringMVC提供了许多自动配置

Inclusion of ContentNegotiatingViewResolver and BeanNameViewResolver beans.
Support for serving static resources, including support for WebJars (covered later in this document)).
Automatic registration of Converter, GenericConverter, and Formatter beans.
Support for HttpMessageConverters (covered later in this document).
Automatic registration of MessageCodesResolver (covered later in this document).
Static index.html support.
Custom Favicon support (covered later in this document).
Automatic use of a ConfigurableWebBindingInitializer bean (covered later in this document).

视图解析器

　　包含了ContentNegotiatingViewResolver和BeanNameViewResolver。

　　在WebMvcAutoConfiguration中定位到ContentNegotiatingViewResolver有关的方法，该方法标注了@Bean，所以会把ContentNegotiatingViewResolver加入容器。根据注释可以看到，ContentNegotiatingViewResolver用于管理所有的ViewResolver，即所有实现了ViewResolver的Bean，然后对于每个View找到最合适的ViewResolver去解析。我们可以向容器中添加自定义视图解析器，添加的自定义视图解析器也会被ContentNegotiatingViewResolver所管理。

        @Bean
        @ConditionalOnBean(ViewResolver.class)
        @ConditionalOnMissingBean(name = "viewResolver",
                value = ContentNegotiatingViewResolver.class)
        public ContentNegotiatingViewResolver viewResolver(BeanFactory beanFactory) {
            ContentNegotiatingViewResolver resolver = new ContentNegotiatingViewResolver();
            resolver.setContentNegotiationManager(
                    beanFactory.getBean(ContentNegotiationManager.class));
            // ContentNegotiatingViewResolver uses all the other view resolvers to locate
            // a view so it should have a high precedence
            resolver.setOrder(Ordered.HIGHEST_PRECEDENCE);
            return resolver;
        }

　　在启动类使用@Bean注解添加自定义ViewResolver，并在doDispatch打上断点，随意发送一个请求，观察ContentNegotiatingViewResolver是否把自定义的myViewResolver收录进去。

@SpringBootApplication
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

    @Bean
    public ViewResolver myViewResolver(){
        return new MyViewResolver();
    }

    private static class MyViewResolver implements ViewResolver{

        @Override
        public View resolveViewName(String s, Locale locale) throws Exception {
            return null;
        }
    }
}

静态资源

转换器与格式化器

　　页面表单提交的数据都是String类型的，当注入pojo的时候需要转换成相应的类型，这一工作由conveter完成。日期格式的转换有转换器完成。SpringBoot自动注入这两种类型的Bean是byType的，即从容器中获取所有Converter Formatter类型的bean并调用相应的add方法，所以如果想添加自定义的转换器、格式化器，同样只需要放到容器里即可。

        @Override
        public void addFormatters(FormatterRegistry registry) {
            for (Converter<?, ?> converter : getBeansOfType(Converter.class)) {
                registry.addConverter(converter);
            }
            for (GenericConverter converter : getBeansOfType(GenericConverter.class)) {
                registry.addConverter(converter);
            }
            for (Formatter<?> formatter : getBeansOfType(Formatter.class)) {
                registry.addFormatter(formatter);
            }
        }

        private <T> Collection<T> getBeansOfType(Class<T> type) {
            return this.beanFactory.getBeansOfType(type).values();
        }

HttpMessageConverters

　　需要自定义HttpMessageConverters，只需要把自己定义的HttpMessageConverters放入容器中，SpringBoot会把HttpMessageConverters添加到SpringMVC中。

    @Bean
    public HttpMessageConverters customConverters() {
        HttpMessageConverter<?> additional = ...
        HttpMessageConverter<?> another = ...
        return new HttpMessageConverters(additional, another);
    }

转载于:https://www.cnblogs.com/AshOfTime/p/10902379.html