SpringBoot首页设置解析(推荐)
这篇文章主要介绍了SpringBoot首页设置解析,本文给大家介绍的非常详细,对大家的学习或工作具有一定的参考借鉴价值,需要的朋友可以参考下
首先来解释一下SpringBoot首页设置的三种方式
1.SpringBoot默认首页设置
编写一个最简单的html文件 index.html
123456789 | <!DOCTYPE html> <html lang= "en" > <head> <meta charset= "UTF-8" > </head> <body> <h1>首页</h1> </body> </html> |
将index.html文件置于SpringBoot的任一静态资源目录下
http://localhost:8080/访问,成功显示
源码分析
首先找对应的自动配置类WebMvcAutoConfiguration中的对应代码
123456789 | @Bean public WelcomePageHandlerMapping welcomePageHandlerMapping(ApplicationContext applicationContext, FormattingConversionService mvcConversionService, ResourceUrlProvider mvcResourceUrlProvider) { WelcomePageHandlerMapping welcomePageHandlerMapping = new WelcomePageHandlerMapping( new TemplateAvailabilityProviders(applicationContext), applicationContext, this .getWelcomePage(), this .mvcProperties.getStaticPathPattern()); welcomePageHandlerMapping.setInterceptors( this .getInterceptors(mvcConversionService, mvcResourceUrlProvider)); welcomePageHandlerMapping.setCorsConfigurations( this .getCorsConfigurations()); return welcomePageHandlerMapping; } |
可以看到 SpringBoot注册了WelcomePageHandlerMappingBean来处理项目的默认首页,构造器中的this.getWelcomePage()为首页资源。
12345678910111213141516171819 | private Resource getWelcomePage() { String[] var1 = this .resourceProperties.getStaticLocations(); int var2 = var1.length; for ( int var3 = 0 ; var3 < var2; ++var3) { String location = var1[var3]; Resource indexHtml = this .getIndexHtml(location); if (indexHtml != null ) { return indexHtml; } } ServletContext servletContext = this .getServletContext(); if (servletContext != null ) { return this .getIndexHtml((Resource)( new ServletContextResource(servletContext, "/" ))); } else { return null ; } } |
分析这段代码,首先获取了this.resourceProperties的StaticLocations字段,顾名思义就是静态路径,那就先跟踪StaticLocations
可以看出StaticLocations是WebPropertis中内部静态类Resources的属性,从构造器中可以看出它的值为
1 | private static final String[] CLASSPATH_RESOURCE_LOCATIONS = new String[]{ "classpath:/META-INF/resources/" , "classpath:/resources/" , "classpath:/static/" , "classpath:/public/" }; |
显而易见,这其实就是SpringBoot的静态资源目录
/META-INF
/resources/
/resources/
/static/
/public/
回到之前的代码,获取了StaticLocations后,通过循环遍历,很明显可以看到一个新的方法this.getIndexHtml(location)
123 | private Resource getIndexHtml(String location) { return this .getIndexHtml( this .resourceLoader.getResource(location)); } |
使用this.resourceLoader返回一个与location对应的Resource执行另一个getIndexHtml()函数
1234567891011 | private Resource getIndexHtml(Resource location) { try { Resource resource = location.createRelative( "index.html" ); if (resource.exists() && resource.getURL() != null ) { return resource; } } catch (Exception var3) { } return null ; } |
很明显,这个方法是获取对应目录下的index.html文件。再往回看
1234567 | for ( int var3 = 0 ; var3 < var2; ++var3) { String location = var1[var3]; Resource indexHtml = this .getIndexHtml(location); if (indexHtml != null ) { return indexHtml; } } |
当找到对应文件的时候就返回对应的资源,这就是SpringBoot设置首页的默认方式的原理。
从源码中也可以看出另一个关于静态资源目录优先级的问题。getWelcomePage遍历静态资源目录,一旦找到就返回,所以优先级和staticLocations中的顺序相对,验证一下。
先在每一个目录下建立对应的indx.html文件
和得出的结论一样,优先级最高的是 /META-INF/resources/,把 /META-INF/resources/下的index.html文件删除再次验证
验证成功!
2.controller里添加"/"的映射路径
新建IndexController.java
12345678910111213 | package com.springboot04webapp.controller; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; @Controller public class IndexController { @RequestMapping ( "/" ) public String index(){ return "indexController" ; } } |
首页资源indexController.html
123456789 | <!DOCTYPE html> <html lang= "en" > <head> <meta charset= "UTF-8" > </head> <body> <h1>indexController首页</h1> </body> </html> |
3.MVC扩展配置实现
新建MyMvcConfiguration配置类,扩展MVC配置,重写addViewControllers方法
1234567891011121314 | package com.springboot04webapp.config; import org.springframework.context.annotation.Configuration; import org.springframework.web.servlet.config.annotation.ViewControllerRegistry; import org.springframework.web.servlet.config.annotation.WebMvcConfigurer; @Configuration public class MyMvcConfiguration implements WebMvcConfigurer { @Override public void addViewControllers(ViewControllerRegistry registry) { registry.addViewController( "/" ).setViewName( "indexMVC" ); } } |
首页资源indexMVC.html
123456789 | <!DOCTYPE html> <html lang= "en" > <head> <meta charset= "UTF-8" > </head> <body> <h1>indexMVC首页</h1> </body> </html> |
扩展:优先级问题
之前的三个方法都是单独设置的,现在把他们结合起来
优先级最高的是第二种方法,然后将indexController删除,再次验证
得出结论:Controller>MyMvcConfiguration>默认方法
到此这篇关于SpringBoot首页设置解析详解的文章就介绍到这了