7.3.1 SpringBoot的web开发:springboot提供的自动配置

7.3.1 SpringBoot的web开发:springboot提供的自动配置

---

1.自动配置的ViewResolver

1.ContentNegotiatingViewResolver
ContentNegotiatingViewResolver不是自己处理View，而是代理给不同的ViewResolver来处理不同的View
  -> 优先级最高

@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;
}

2.BeanNameViewResolver

在Controller中的一个返回值为字符串(视图名)，会根据BeanNameViewResolver去查找Bean(名称为返回字符串)的View来渲染视图

@Bean
@ConditionalOnBean(View.class)
@ConditionalOnMissingBean
public BeanNameViewResolver beanNameViewResolver() {
   BeanNameViewResolver resolver = new BeanNameViewResolver();
   resolver.setOrder(Ordered.LOWEST_PRECEDENCE - 10);
   return resolver;
}

3.InternalResourceViewResolver

是一个极为常用的ViewResolver
 -> 通过设置前缀，后缀及控制器中的方法来返回视图名称的字符串，得到实际界面

@Bean
@ConditionalOnMissingBean
public InternalResourceViewResolver defaultViewResolver() {
   InternalResourceViewResolver resolver = new InternalResourceViewResolver();
   resolver.setPrefix(this.mvcProperties.getView().getPrefix());
   resolver.setSuffix(this.mvcProperties.getView().getSuffix());
   return resolver;
}

---

2.自动配置静态资源
在自动配置类中的addResourceHandlers方法中定义了以下 的静态资源的自动配置

1.类路径文件
  会把类路径下的文件映射为 -> /** 通过8080/**来访问
  "classpath:/META-INF/resources/", "classpath:/resources/","classpath:/static/", "classpath:/public/“

2.webJar路径

  就是把常用的脚本框架封装在jar包下
  把/META-INF/resource/webjar/下的静态文件映射为/webjar/**
  -> 通过8080/webjar/**访问（见swagger-ui）

3.自动配置Formatter和Converter

  如下面的addFormatters，只要定义了Convert，Formatter的接口实现类，就会被注册到Bean中去

4.静态首页的支持

  只要报index.html放在
  classpath:/META-INF/resources/index.html
  classpath:/resources/index.html
  classpath:/static/index.html
  classpath:/public/index.html

举例：

1.类路径文件
  会把类路径下的文件映射为 -> /** 通过8080/**来访问
  "classpath:/META-INF/resources/", "classpath:/resources/","classpath:/static/", "classpath:/public/

@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
   if (!this.resourceProperties.isAddMappings()) {
      logger.debug("Default resource handling disabled");
      return;
   }
   Integer cachePeriod = this.resourceProperties.getCachePeriod();
   if (!registry.hasMappingForPattern("/webjars/**")) {
      customizeResourceHandlerRegistration(
            registry.addResourceHandler("/webjars/**")
                  .addResourceLocations(
                        "classpath:/META-INF/resources/webjars/")
            .setCachePeriod(cachePeriod));
   }
   String staticPathPattern = this.mvcProperties.getStaticPathPattern();
   if (!registry.hasMappingForPattern(staticPathPattern)) {
      customizeResourceHandlerRegistration(
            registry.addResourceHandler(staticPathPattern)
                  .addResourceLocations(
                        this.resourceProperties.getStaticLocations())
            .setCachePeriod(cachePeriod));
   }
}


@ConfigurationProperties(prefix = "spring.resources", ignoreUnknownFields = false)
public class ResourceProperties implements ResourceLoaderAware {

   private static final String[] SERVLET_RESOURCE_LOCATIONS = { "/" };

   private static final String[] CLASSPATH_RESOURCE_LOCATIONS = {
         "classpath:/META-INF/resources/", "classpath:/resources/",
         "classpath:/static/", "classpath:/public/" };

2.webJar路径

  就是把常用的脚本框架封装在jar包下
  把/META-INF/resource/webjar/下的静态文件映射为/webjar/**
  -> 通过8080/webjar/**访问（见swagger-ui）
webjar路径

3.自动配置Formatter和Converter

  如下面的addFormatters，只要定义了Convert，Formatter的接口实现类，就会被注册到Bean中去

@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);
   }
}