微服务架构Day03-SpringBoot之web开发配置

XxxAutoConfiguration:帮我们给容器中自动配置组件
XxxProperties：配置类，封装配置文件中的内容

@ConfigurationProperties(
    prefix = "spring.resources",
    ignoreUnknownFields = false
)

 /* 
  * ResourceHandlerRegistry存储用于通过Spring MVC服务静态资源的资源处理程序的注册
  * 允许设置为在Web浏览器中高效加载而优化的缓存头
  * 可以在Web应用的目录下,类路径等位置之外的位置提供资源
  */
 public void addResourceHandlers(ResourceHandlerRegistry registry) { 
            if (!this.resourceProperties.isAddMappings()) {
                logger.debug("Default resource handling disabled");
            } else {
                Duration cachePeriod = this.resourceProperties.getCache().getPeriod();
                CacheControl cacheControl = this.resourceProperties.getCache().getCachecontrol().toHttpCacheControl();
                if (!registry.hasMappingForPattern("/webjars/**")) {
                    this.customizeResourceHandlerRegistration(registry.addResourceHandler(new String[]{"/webjars/**"}).addResourceLocations(new String[]{"classpath:/META-INF/resources/webjars/"}).setCachePeriod(this.getSeconds(cachePeriod)).setCacheControl(cacheControl));
                }

                String staticPathPattern = this.mvcProperties.getStaticPathPattern();
                if (!registry.hasMappingForPattern(staticPathPattern)) {
                    this.customizeResourceHandlerRegistration(registry.addResourceHandler(new String[]{staticPathPattern}).addResourceLocations(getResourceLocations(this.resourceProperties.getStaticLocations())).setCachePeriod(this.getSeconds(cachePeriod)).setCacheControl(cacheControl));
                }

            }
        }

classpath:/META-INF/resources/
classpath:/resources/
classpath:/static/
classpath:/public/
/	# 当前项目的根路径

 @Bean
        public WelcomePageHandlerMapping welcomePageHandlerMapping(ApplicationContext applicationContext) {
            return new WelcomePageHandlerMapping(new TemplateAvailabilityProviders(applicationContext), applicationContext, this.getWelcomePage(), this.mvcProperties.getStaticPathPattern());
        }

        @Configuration
        @ConditionalOnProperty(
            value = {"spring.mvc.favicon.enabled"},
            matchIfMissing = true
        )

		/* 
		 * ResourceLoaderAware是一个标记接口
		 * 用于通过ApplicationContext上下文注入ResourceLoader
		 * 有setResourceLoader()方法
		 */
        public static class FaviconConfiguration implements ResourceLoaderAware {
            private final ResourceProperties resourceProperties;
            /* 
             * ResourceLoader用于返回Resource对象和ClassLoader对象
             * 		- getResource(String location)方法根据提供的location参数返回相应的Resource对象
             * 		- getClassLoader()方法则返回加载这些Resource的ClassLoader
             */
            private ResourceLoader resourceLoader;

            public FaviconConfiguration(ResourceProperties resourceProperties) {
                this.resourceProperties = resourceProperties;
            }

            public void setResourceLoader(ResourceLoader resourceLoader) {
                this.resourceLoader = resourceLoader;
            }

			/* 
			 * SimpleUrlHandlerMapping是SpringMVC中适应性最强的Handler Mapping类
			 * 允许明确指定URL模式和Handler的映射关系.有两种声明方式:
			 * 		- prop:
			 * 		  - key: URL模式
			 * 		  — value: Handler的ID或者名字
			 * 		- value:
			 * 		  - 等号左边是URL模式
			 * 		  - 等号右边是HandlerID或者名字  
			 */
            @Bean
            public SimpleUrlHandlerMapping faviconHandlerMapping() {
                SimpleUrlHandlerMapping mapping = new SimpleUrlHandlerMapping();
                mapping.setOrder(-2147483647);
                mapping.setUrlMap(Collections.singletonMap("**/favicon.ico", this.faviconRequestHandler()));
                return mapping;
            }

		<properties>	
			<!-- 切换thymeleaf版本 -->
			<thymeleaf.version>3.0.2.RELEASE</thymeleaf.version>
			<!-- 布局功能支持程序-thymeleaf3==layout2  thymeleaf2==layout1 -->
			<thymeleaf-layout-dialect.version>2.1.1</thymeleaf-layout-dialect.version>	
		</properties>
		<dependency>	
			<!-- 引入thymeleaf依赖 -->
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>

@ConfigurationProperties(
    prefix = "spring.thymeleaf"
)
public class ThymeleafProperties {
    private static final Charset DEFAULT_ENCODING;
    public static final String DEFAULT_PREFIX = "classpath:/templates/";
    public static final String DEFAULT_SUFFIX = ".html";
    private boolean checkTemplate = true;
    private boolean checkTemplateLocation = true;
    private String prefix = "classpath:/templates/";
    private String suffix = ".html";	
    private String mode = "HTML";
    private Charset encoding;

<html xmlns:th="http://www.thymeleaf.org">

Simple expressions:						(表达式语法)
Variable Expressions: ${...}			(获取变量值-OGNL)
					1.获取对象的属性，调用方法
					2.使用内置的基本对象：
						#ctx : the context object.
						#vars: the context variables.
						#locale : the context locale.
						#request : (only in Web Contexts) the HttpServletRequest object.
						#response : (only in Web Contexts) the HttpServletResponse object.
						#session : (only in Web Contexts) the HttpSession object.
						#servletContext : (only in Web Contexts) the ServletContext object.
					3.内置的工具对象：
						#execInfo : information about the template being processed.
						#messages : methods for obtaining externalized messages inside variables expressions, in the same way as they would be obtained using #{…} syntax.
						#uris : methods for escaping parts of URLs/URIs
						#conversions : methods for executing the configured conversion service (if any).
						#dates : methods for java.util.Date objects: formatting, component extraction, etc.
						#calendars : analogous to #dates , but for java.util.Calendar objects.
						#numbers : methods for formatting numeric objects.
						#strings : methods for String objects: contains, startsWith, prepending/appending, etc.
						#objects : methods for objects in general.
						#bools : methods for boolean evaluation.
						#arrays : methods for arrays.
						#lists : methods for lists.
						#sets : methods for sets.
						#maps : methods for maps.
						#aggregates : methods for creating aggregates on arrays or collections.
						#ids : methods for dealing with id attributes that might be repeated (for example, as a result of an iteration).
Selection Variable Expressions: *{...}		(选择表达式，和${}在用法上大体一致)
								补充：配合th:object="${session.user}"
								<div th:object="${session.user}">
									<p>Name: <span th:text="*{firstName}">Sebastian</span>.</p>
									<p>Surname: <span th:text="*{lastName}">Pepper</span>.</p>
									<p>Nationality: <span th:text="*{nationality}">Saturn</span>.</p>
								</div>
Which is exactly equivalent to:
								<div>
									<p>Name: <span th:text="${session.user.firstName}">Sebastian</span>.</p>
									<p>Surname: <span th:text="${session.user.lastName}">Pepper</span>.</p>
									<p>Nationality: <span th:text="${session.user.nationality}">Saturn</span>.</p>
								</div>
Message Expressions: #{...}					(获取国际化内容)
Link URL Expressions: @{...}				(定义url)
<a href="details.html"
th:href="@{http://localhost:8080/gtvg/order/details(orderId=${o.id})}">view</a>
<!-- Will produce '/gtvg/order/details?orderId=3' (plus rewriting) -->
<a href="details.html" th:href="@{/order/details(orderId=${o.id})}">view</a>
<!-- Will produce '/gtvg/order/3/details' (plus rewriting) -->
<a href="details.html" th:href="@{/order/{orderId}/details(orderId=${o.id})}">view</a>
Fragment Expressions: ~{...}				(片段引用表达式)	

Literals(字面量)
	Text literals: 'one text' , 'Another one!' ,…
	Number literals: 0 , 34 , 3.0 , 12.3 ,…
	Boolean literals: true , false
	Null literal: null
	Literal tokens: one , sometext , main ,…
Text operations		(文本操作)
	String concatenation: +
	Literal substitutions: |The name is ${name}|
	Arithmetic operations		(数学运算)
	Binary operators: + , - , * , / , %
	Minus sign (unary operator): -
Boolean operations		(布尔运算)
	Binary operators: and , or
	Boolean negation (unary operator): ! , not
Comparisons and equality		(比较运算)
	Comparators: > , < , >= , <= ( gt , lt , ge , le )
	Equality operators: == , != ( eq , ne )
Conditional operators(条件运算)
	If-then: (if) ? (then)
	If-then-else: (if) ? (then) : (else)
	Default: (value) ?: (defaultvalue)
Special tokens(特殊操作)
	No-Operation: _		

@Import({WebMvcAutoConfiguration.EnableWebMvcConfiguration.class})

 @Configuration
    public static class EnableWebMvcConfiguration extends DelegatingWebMvcConfiguration {

  //
  @Autowired(
        required = false
    )
    public void setConfigurers(List<WebMvcConfigurer> configurers) {
        if (!CollectionUtils.isEmpty(configurers)) {
            this.configurers.addWebMvcConfigurers(configurers);
        }

    }

 //将所有的WebMvcConfigurer相关的配置都调用一遍
 public void addViewControllers(ViewControllerRegistry registry) {
        Iterator var2 = this.delegates.iterator();

        while(var2.hasNext()) {
            WebMvcConfigurer delegate = (WebMvcConfigurer)var2.next();
            delegate.addViewControllers(registry);
        }

    }

@Import({DelegatingWebMvcConfiguration.class})
public @interface EnableWebMvc {
}

@Configuration
public class DelegatingWebMvcConfiguration extends WebMvcConfigurationSupport {

@Configuration
@ConditionalOnWebApplication(
    type = Type.SERVLET
)
@ConditionalOnClass({Servlet.class, DispatcherServlet.class, WebMvcConfigurer.class})
@ConditionalOnMissingBean({WebMvcConfigurationSupport.class})	//当容器中没有此组件时，此自动配置类才生效
@AutoConfigureOrder(-2147483638)
@AutoConfigureAfter({DispatcherServletAutoConfiguration.class, TaskExecutionAutoConfiguration.class, ValidationAutoConfiguration.class})