1、基本配置
|-- 1.1 入口类和@SpringBootApplication
    |-- @Target(ElementType.TYPE)
        @Retention(RetentionPolicy.RUNTIME)
        @Documented
        @Inherited
        @Configuration
        @EnableAutoConfiguration
        @ComponentScan
        public @interface SpringBootApplication {
            Class<?> exclude() default {};
            String[] excludeName() default {};
        }
|-- 1.2 关闭特定的
    @SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
|-- 1.3 定制banner
    |-- src
        |-- main
            |-- resources 
                |-- banner.txt
                    spring字样
    |-- 开户banner
        替换即可
    |-- 关闭banner
    main {
        app = new SpringApplication(Ch522Application.class);
        app.setShowBanner(false);
        app.run(args);
        
        // 或者
        new SpringApplicationBuilder(Ch522Application.class)
            .showBanner(false)
            .run(args);
    }
|-- 1.4 Spring boot 的配置文件
    |-- application.properties
        server.port=9090
        server.context-path=/helloboot
    |-- application.yml
        server:
            port: 9090
            context-path: helloboot
|-- 1.5 使用xml配置
    @ImportSource({"classpath:some-context.xml", "classpath:another-context.xml"})

2、外部配置
2.1 命令行参数：
java -jar xx.jar --server.port=9090
2.2 常规属性配置：
|-- application.properties
    book.author=zhangsan
    book.name=springboot
|-- @RestController
    @SpringBootApplication
    Ch522Application {
        @Value("book.author")
        private String bookAuthor;
        @Value("book.name")
        private String bookName;
        @RequestMapping("/")
        String index() {
            return "book name is:" + bookName + " and book author is:" + bookAuthor;
        }
        public static void main(String[] args) {
            SpringApplication.run(Ch522Application.class, args);
        }
    }
2.3 类型安全配置（基于properties）
|-- application.properties
    author.name=wyf
    author.age=32
|-- @Component
    @ConfigurationProperties(prefix = "author")
    public class AuthorSettings {
        private String name;
        private Long age;
        
        // setter、getter
    }
2.4 Profile配置
|-- application-prod.properties
    server.port=80
|-- application-dev.properties
    server.port=8888
|-- application.properties
    spring.profiles.active=dev
2.5 spring boot运行原理 
开启debug模式：
（1）运行jar时增加--debug参数 
    java -jar xx.jar --debug
（2）在application.properties中设置属性
    debug=true
（3）在STS中设置
    VM arguments
        -Ddebug
2.5.1 运作原理：
    |-- @Target(ElementType.TYPE)
        @Retention(RetentionPolicy.RUNTIME)
        @Documented
        @Inherited
        @Import({EnableAutoConfigurationImportSelector.class, 
            AutoConfigurationPackages.Registrar.class })
        public @interface EnableAutoConfiguration {
            Class<?> exclude() default {};
            String[] excludeName() default {};
        }
        |-- EnableAutoConfigurationImportSelector
            -> 使用SpringFactoriesLoader.loadFactoryNames方法扫描具有META-INF/spring.factories的jar
                -> 而spring-boot-autoconfigure-1.3.0.x.jar里就有一个spring.factories，此文件申明了一些自动配置
2.5.2 核心注解
    打开spring.factories文件下的xxAutoConfiguration文件
    |-- @ConditionalOnBean：当容器有指定的Bean条件下
    |-- @ConditionalOnClass：当类路径下有指定的类的条件下
    |-- @ConditionalOnExpression：基于SpEL表达式作为判断条件
    |-- @ConditionalOnWebApplication：当前项目是Web项目的条件下
    ...
    |-- @Target(ElementType.TYPE)
        @Retention(RetentionPolicy.RUNTIME)
        @Documented
        @Conditional
        public @interface ConditionalOnWebApplication {
            
        }

3. Spring Web
1、静态首页的支持：
    classpath:/META-INF/resources/index.html
    classpath:/resources/index.html
    classpath:/static/index.html
    classpath:/public/index.html
2、接管Springboot的web配置
    @Configuration
    public class WebMvcConfig extends WebMvcConfigurerAdapter {
        @Override
        public void addViewControllers(ViewControllerRegitry registry) { // 与springboot自动配置同时生效
            registry.addViewController("/xx").setViewName("/xx");
        }
    }
3、注册Servlet、Filter、Listener
    （1）直接注册Bean示例
        @Bean
        public XxServlet xxServlet() {
            return new XxServlet();
        }
        @Bean 
        public YyFilter yyFilter() {
            return new YyFilter();
        }
        @Bean
        public ZzListener zzListener() {
            return new ZzListener();
        }
    （2）通过RegistrationBean
        @Bean
        public ServletRegistrationBean xxServlet() {
            return new ServletRegistrationBean(new XxServlet(), "/xx/*");
        }
        @Bean
        public FilterRegistrationBean xxServlet() {
            FilterRegistrationBean registrationBean = new FilterRegistrationBean();
            registrationBean.setFilter(new YyFilter());
            registrationBean.setOrder(2);
            return registrationBean;
        }
        @Bean
        public ServletListenerRegistrationBean xxServlet() {
            return new ServletListenerRegistrationBean<ZzListener>(new ZzListener());
        }
待续。。。