springmvc配置mysql8 springmvc配置静态资源

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墨舞天涯 2023-08-23 21:14:23

文章标签 springmvc配置mysql8 spring spring boot java 静态资源 文章分类 MySQL 数据库

`WEB`开发

1.`SpringMVC`自动配置概览

springmvc配置mysql8 springmvc配置静态资源_静态资源

Spring Boot provides auto-configuration for Spring MVC that works well with most applications.(大多场景我们都无需自定义配置)

The auto-configuration adds the following features on top of Spring’s defaults:

Inclusion of ContentNegotiatingViewResolver and BeanNameViewResolver beans.

内容协商视图解析器和BeanName视图解析器

Support for serving static resources, including support for WebJars (covered later in this document)).

静态资源（包括webjars）

Automatic registration of Converter, GenericConverter, and Formatter beans.

自动注册 Converter，GenericConverter，Formatter

Support for HttpMessageConverters (covered later in this document).

支持 HttpMessageConverters （后来我们配合内容协商理解原理）

Automatic registration of MessageCodesResolver (covered later in this document).

自动注册 MessageCodesResolver （国际化用）

Static index.html support.

静态index.html 页支持

Custom Favicon support (covered later in this document).

自定义 Favicon

Automatic use of a ConfigurableWebBindingInitializer bean (covered later in this document).

自动使用 ConfigurableWebBindingInitializer ，（DataBinder负责将请求数据绑定到JavaBean上）

If you want to keep those Spring Boot MVC customizations and make more MVC customizations (interceptors, formatters, view controllers, and other features), you can add your own @Configuration class of type WebMvcConfigurer but without @EnableWebMvc.
不用@EnableWebMvc注解。使用 **@Configuration** + **WebMvcConfigurer** 自定义规则
If you want to provide custom instances of RequestMappingHandlerMapping, RequestMappingHandlerAdapter, or ExceptionHandlerExceptionResolver, and still keep the Spring Boot MVC customizations, you can declare a bean of type WebMvcRegistrations and use it to provide custom instances of those components.
声明 **WebMvcRegistrations** 改变默认底层组件
If you want to take complete control of Spring MVC, you can add your own @Configuration annotated with @EnableWebMvc, or alternatively add your own @Configuration-annotated DelegatingWebMvcConfiguration as described in the Javadoc of @EnableWebMvc.
使用 **@EnableWebMvc+@Configuration+@DelegatingWebMvcConfiguration 全面接管SpringMVC**

2.简单功能分析

A.静态资源目录[非常重要]

只能静态资源放在类路径下：/static or /public or / resources or /META-INF/resources

访问：当前项目根路径:/+静态资源名

通过访问： 当前项目根路径:/+静态资源名能找到静态资源原理是：静态映射是/**[表示是对所有请求进行处理]

原理是：当请求进来时，先去找Controller看Controller类方法能不能处理，不能处理的所有请求又都交给静态资源处理器[原因是静态资源映射是：/**]，如果静态资源能找到，则响应静态资源，静态资源也找不到，则报404页面

在Spring家庭中/**表示拦截所有，而在web中/*表示拦截所有

1.修改静态资源访问前缀【非常重要】

在SpringBoot默认是无前缀的

修改默认前缀：在核心配置文件中

#修改静态资源访问前缀
spring:
  mvc:
    static-path-pattern: /stat/**  #表示访问资源都必须带上/stat/静态资源名称
    
    #表示访问资源都必须带上/static/静态资源名称

访问方式：当前项目+static-path-pattern[等价上面的/stat/]+静态资源名 = 静态资源文件夹下找

2.修改静态资源放在的文件夹

#修改静态资源访问前缀
spring:
  #必须将静态资源放在haikang文件夹下才能生效
  web:
    resources:
      static-locations: [classpath:/haikang/] #必须将静态资源放在haikang文件夹下才能生效

必须要将静态资源放在haikang目录才能生效

访问路径：当前项目+加上静态资源名【注意是：如果有静态资源访问前缀必须在当前项目后加载访问前缀【如：[(http://localhost/stat/f.jpg)前缀是stat】】

B.欢迎页支持

欢迎页支持的两种方式：

方式一：静态资源路径下：文件名为：index.html会自动当成欢迎页

注意是：文件名一定为index.html，并且要放在静态资源路径下，并且要关闭前端前缀

#修改静态资源访问前缀
spring:
#  mvc:
#    static-path-pattern: /stat/**  #表示访问资源都必须带上/static/静态资源名称
  #必须将静态资源放在haikang文件夹下才能生效

方式二：controller处理index欢迎页

C.自定义`Favicon`【自定义访问地址栏显示小图标】

一定要将小图标放在静态资源目录下，并且名称为必须为：favicon.ico

$[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-3IODiF9R-1655558388864)(D:\typora笔记\springboot\img\1654342599999.png)]$

D.静态资源配置原理【重点】

SpringBoot启动默认加载 xxxAutoConfiguration类（自动配置类）

SpringMVC功能的自动配置类WebMvcAutoConfiguration生效

@Configuration(proxyBeanMethods = false)是一个配置类
@ConditionalOnWebApplication(type = Type.SERVLET)是否是原生态橡Servlet
@ConditionalOnClass({ Servlet.class, DispatcherServlet.class, WebMvcConfigurer.class })在容器中是否有Servlet，DispatcherServlet  WebMvcConfigurer这三组件
@ConditionalOnMissingBean(WebMvcConfigurationSupport.class)
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE + 10)
@AutoConfigureAfter({ DispatcherServletAutoConfiguration.class, TaskExecutionAutoConfiguration.class,
		ValidationAutoConfiguration.class })
public class WebMvcAutoConfiguration {}

给容器配置什么

@Configuration(proxyBeanMethods = false)
	@Import(EnableWebMvcConfiguration.class)
	@EnableConfigurationProperties({ WebMvcProperties.class, ResourceProperties.class })
	@Order(0)
	public static class WebMvcAutoConfigurationAdapter implements WebMvcConfigurer {}

配置文件的相关属性和xxx进行了绑定。WebMvcProperties==spring.mvc、ResourceProperties==spring.resources

1.当配置类中只有一个有构造器时，有参构造器中的所有参数都是从容器中传入

//有参构造器所有参数的值都会从容器中确定
//ResourceProperties resourceProperties；获取和spring.resources绑定的所有的值的对象
//WebMvcProperties mvcProperties 获取和spring.mvc绑定的所有的值的对象
//ListableBeanFactory beanFactory Spring的beanFactory
//HttpMessageConverters 找到所有的HttpMessageConverters
//ResourceHandlerRegistrationCustomizer 找到 资源处理器的自定义器。=========
//DispatcherServletPath  
//ServletRegistrationBean   给应用注册Servlet、Filter....
	public WebMvcAutoConfigurationAdapter(ResourceProperties resourceProperties, WebMvcProperties mvcProperties,
				ListableBeanFactory beanFactory, ObjectProvider<HttpMessageConverters> messageConvertersProvider,
				ObjectProvider<ResourceHandlerRegistrationCustomizer> resourceHandlerRegistrationCustomizerProvider,
				ObjectProvider<DispatcherServletPath> dispatcherServletPath,
				ObjectProvider<ServletRegistrationBean<?>> servletRegistrations) {
			this.resourceProperties = resourceProperties;
			this.mvcProperties = mvcProperties;
			this.beanFactory = beanFactory;
			this.messageConvertersProvider = messageConvertersProvider;
			this.resourceHandlerRegistrationCustomizer = resourceHandlerRegistrationCustomizerProvider.getIfAvailable();
			this.dispatcherServletPath = dispatcherServletPath;
			this.servletRegistrations = servletRegistrations;
		}

2.资源处理的默认规则

@Override
		public void addResourceHandlers(ResourceHandlerRegistry registry) {
			if (!this.resourceProperties.isAddMappings()) {
				logger.debug("Default resource handling disabled");
				return;
			}
			Duration cachePeriod = this.resourceProperties.getCache().getPeriod();
			CacheControl cacheControl = this.resourceProperties.getCache().getCachecontrol().toHttpCacheControl();
			//webjars的规则
            if (!registry.hasMappingForPattern("/webjars/**")) {
				customizeResourceHandlerRegistration(registry.addResourceHandler("/webjars/**")
						.addResourceLocations("classpath:/META-INF/resources/webjars/")
						.setCachePeriod(getSeconds(cachePeriod)).setCacheControl(cacheControl));
			}
            
            //
			String staticPathPattern = this.mvcProperties.getStaticPathPattern();
			if (!registry.hasMappingForPattern(staticPathPattern)) {
				customizeResourceHandlerRegistration(registry.addResourceHandler(staticPathPattern)
						.addResourceLocations(getResourceLocations(this.resourceProperties.getStaticLocations()))
						.setCachePeriod(getSeconds(cachePeriod)).setCacheControl(cacheControl));
			}
		}

上述源码可看出：我们可以禁用所有静态资源规则，只需要在核心配置文件修改

spring:
	resources:
		add-mappings: false  #false时禁用所有静态资源规则 ，默认值是：true

3.因为在默认静态资源下，将静态资源放在/META-INF/resources/ /static/ /public/ /resources/ 能够直接访问，源码如下：

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

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

	/**
	 * Locations of static resources. Defaults to classpath:[/META-INF/resources/,
	 * /resources/, /static/, /public/].
	 */
	private String[] staticLocations = CLASSPATH_RESOURCE_LOCATIONS;

4.欢迎页处理

HandlerMapping：处理器映射。保存了每一个Handler能处理哪些请求。	

	@Bean
		public WelcomePageHandlerMapping welcomePageHandlerMapping(ApplicationContext applicationContext,
				FormattingConversionService mvcConversionService, ResourceUrlProvider mvcResourceUrlProvider) {
			WelcomePageHandlerMapping welcomePageHandlerMapping = new WelcomePageHandlerMapping(
					new TemplateAvailabilityProviders(applicationContext), applicationContext, getWelcomePage(),
					this.mvcProperties.getStaticPathPattern());
			welcomePageHandlerMapping.setInterceptors(getInterceptors(mvcConversionService, mvcResourceUrlProvider));
			welcomePageHandlerMapping.setCorsConfigurations(getCorsConfigurations());
			return welcomePageHandlerMapping;
		}

	WelcomePageHandlerMapping(TemplateAvailabilityProviders templateAvailabilityProviders,
			ApplicationContext applicationContext, Optional<Resource> welcomePage, String staticPathPattern) {
		if (welcomePage.isPresent() && "/**".equals(staticPathPattern)) {
            //要用欢迎页功能，必须是/**，说明不能配置静态资源前缀
			logger.info("Adding welcome page: " + welcomePage.get());
			setRootViewName("forward:index.html");
		}
		else if (welcomeTemplateExists(templateAvailabilityProviders, applicationContext)) {
            // 调用Controller  /index
			logger.info("Adding welcome page template: index");
			setRootViewName("index");
		}
	}

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