<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    modelVersion>4.0.0</groupId>com.exampleartifactId>springbootdemoversion>0.0.1-SNAPSHOTpackaging>warbuild />
    parent>
        >org.springframework.boot>spring-boot-starter-parent>1.3.4.RELEASEdependenciesdependency>
            >spring-boot-starter-web>
project>

package com.example;

import org.springframework.boot.SpringApplication;
 org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 org.springframework.stereotype.Controller;
 org.springframework.web.bind.annotation.RequestMapping;
 org.springframework.web.bind.annotation.ResponseBody;

@Controller
@EnableAutoConfiguration
public class HelloController {

    @RequestMapping("/hello")
    @ResponseBody
    String home() {
        return "Hello,spring boot!";
    }

    static void main(String[] args) throws Exception {
        SpringApplication.run(HelloController.,args);
        //运行之后在浏览器中访问：http://localhost:8080/hello
    }
    
}

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__,| / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.3.4.RELEASE)

2016-05-10 15:21:46.299  INFO 6668 --- [           main] com.example.HelloController              : Starting HelloController on 0KE99GYM83Y5KGX with PID 6668 (D:\newspace\springbootdemo\target\classes started by Administrator in D:\newspace\springbootdemo)
2016-05-10 15:21:46.301  INFO 6668 --- [           main] com.example.HelloController              : No active profile set,falling back to default profiles: default
2016-05-10 15:21:46.337  INFO 6668 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@18b8315: startup date [Tue May 10 15:21:46 CST 2016]; root of context hierarchy
2016-05-10 15:21:47.385  INFO 6668 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2016-05-10 15:21:47.399  INFO 6668 --- [           main] o.apache.catalina.core.StandardService   : Starting service Tomcat
2016-05-10 15:21:47.400  INFO 6668 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.0.33
2016-05-10 15:21:47.482  INFO 6668 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2016-05-10 15:21:47.482  INFO 6668 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1148 ms
2016-05-10 15:21:47.714  INFO 6668 --- [ost-startStop-1] o.s.b.c.e.ServletRegistrationBean        : Mapping servlet: 'dispatcherServlet' to [/]
2016-05-10 15:21:47.718  INFO 6668 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'characterEncodingFilter' to: [/*]
2016-05-10 15:21:47.718  INFO 6668 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2016-05-10 15:21:47.718  INFO 6668 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2016-05-10 15:21:47.718  INFO 6668 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'requestContextFilter' to: [/*]
2016-05-10 15:21:47.939  INFO 6668 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@18b8315: startup date [Tue May 10 15:21:46 CST 2016]; root of context hierarchy
2016-05-10 15:21:47.991  INFO 6668 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/hello]}" onto java.lang.String com.example.HelloController.home()
2016-05-10 15:21:47.993  INFO 6668 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String,java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2016-05-10 15:21:47.994  INFO 6668 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2016-05-10 15:21:48.014  INFO 6668 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2016-05-10 15:21:48.014  INFO 6668 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2016-05-10 15:21:48.048  INFO 6668 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [ org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2016-05-10 15:21:48.128  INFO 6668 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2016-05-10 15:21:48.187  INFO 6668 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2016-05-10 15:21:48.190  INFO 6668 --- [           main] com.example.HelloController              : Started HelloController in 2.166 seconds (JVM running for 2.401)
2016-05-10 15:22:03.171  INFO 6668 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring FrameworkServlet 'dispatcherServlet'
2016-05-10 15:22:03.171  INFO 6668 --- [nio-8080-exec-1] o.s.web.servlet.dispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization started
2016-05-10 15:22:03.181  INFO 6668 --- [nio-8080-exec-1] o.s.web.servlet.dispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization completed in 10 ms

@Bean
public ServletRegistrationBean customServlet() {
    return new ServletRegistrationBean(new CustomServlet(), "/custom");
}

private static class CustomServlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.getWriter().write("receive by custom servlet");
    }
}

@SpringBootApplication
@ServletComponentScan
public class EmbeddedServletApplication {
 ... 
}

@WebServlet(urlPatterns = "/simple")
public class SimpleServlet extends HttpServlet {

    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.getWriter().write("receive by SimpleServlet");
    }
}

@Bean(name = "dispatcherServlet")
public DispatcherServlet myDispatcherServlet() {
    return new DispatcherServlet();
}

<servlet>
    <servlet-name>dispatcher</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:spring-mvc.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
    <servlet-name>dispatcher</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

public class ServletRegistrationBean extends RegistrationBean {
    //存放目标Servlet实例
    private Servlet servlet;
    //存放Servlet的urlMapping
    private Set<String> urlMappings;
    private boolean alwaysMapUrl;
    private int loadOnStartup;
    private MultipartConfigElement multipartConfig;


    public ServletRegistrationBean(Servlet servlet, String... urlMappings) {
        this(servlet, true, urlMappings);
    }

    public ServletRegistrationBean(Servlet servlet, boolean alwaysMapUrl, String... urlMappings) {
        this.urlMappings = new LinkedHashSet();
        this.alwaysMapUrl = true;
        this.loadOnStartup = -1;
        Assert.notNull(servlet, "Servlet must not be null");
        Assert.notNull(urlMappings, "UrlMappings must not be null");
        this.servlet = servlet;
        this.alwaysMapUrl = alwaysMapUrl;
        this.urlMappings.addAll(Arrays.asList(urlMappings));
    }
    
    public void onStartup(ServletContext servletContext) throws ServletException {
        Assert.notNull(this.servlet, "Servlet must not be null");
        String name = this.getServletName();
        if (!this.isEnabled()) {
            logger.info("Servlet " + name + " was not registered (disabled)");
        } else {
            logger.info("Mapping servlet: ''" + name + "'' to " + this.urlMappings);
            Dynamic added = servletContext.addServlet(name, this.servlet);
            if (added == null) {
                logger.info("Servlet " + name + " was not registered (possibly already registered?)");
            } else {
                this.configure(added);
            }
        }
    }
    
    //略
}

public class FilterRegistrationBean extends AbstractFilterRegistrationBean {
    //存放目标Filter对象
    private Filter filter;

    public FilterRegistrationBean() {
        super(new ServletRegistrationBean[0]);
    }

    public FilterRegistrationBean(Filter filter, ServletRegistrationBean... servletRegistrationBeans) {
        super(servletRegistrationBeans);
        Assert.notNull(filter, "Filter must not be null");
        this.filter = filter;
    }

    public Filter getFilter() {
        return this.filter;
    }

    public void setFilter(Filter filter) {
        Assert.notNull(filter, "Filter must not be null");
        this.filter = filter;
    }
}

abstract class AbstractFilterRegistrationBean extends RegistrationBean {
    private static final EnumSet<DispatcherType> ASYNC_DISPATCHER_TYPES;
    private static final EnumSet<DispatcherType> NON_ASYNC_DISPATCHER_TYPES;
    private static final String[] DEFAULT_URL_MAPPINGS;
    private Set<ServletRegistrationBean> servletRegistrationBeans = new LinkedHashSet();
    private Set<String> servletNames = new LinkedHashSet();
    private Set<String> urlPatterns = new LinkedHashSet();
    //重写onStartup方法
    public void onStartup(ServletContext servletContext) throws ServletException {
        Filter filter = this.getFilter();
        Assert.notNull(filter, "Filter must not be null");
        String name = this.getOrDeduceName(filter);
        if (!this.isEnabled()) {
            this.logger.info("Filter " + name + " was not registered (disabled)");
        } else {
            Dynamic added = servletContext.addFilter(name, filter);
            if (added == null) {
                this.logger.info("Filter " + name + " was not registered (possibly already registered?)");
            } else {
                this.configure(added);
            }
        }
    }
    //略...
}

public class ServletListenerRegistrationBean<T extends EventListener> extends RegistrationBean {
    //存放了目标listener
    private T listener;

    public ServletListenerRegistrationBean() {
    }

    public ServletListenerRegistrationBean(T listener) {
        Assert.notNull(listener, "Listener must not be null");
        Assert.isTrue(isSupportedType(listener), "Listener is not of a supported type");
        this.listener = listener;
    }

    public void setListener(T listener) {
        Assert.notNull(listener, "Listener must not be null");
        Assert.isTrue(isSupportedType(listener), "Listener is not of a supported type");
        this.listener = listener;
    }

    public void onStartup(ServletContext servletContext) throws ServletException {
        if (!this.isEnabled()) {
            logger.info("Listener " + this.listener + " was not registered (disabled)");
        } else {
            try {
                servletContext.addListener(this.listener);
            } catch (RuntimeException var3) {
                throw new IllegalStateException("Failed to add listener ''" + this.listener + "'' to servlet context", var3);
            }
        }
    }
    //略...
}

public abstract class RegistrationBean implements ServletContextInitializer, Ordered {
    ...
}
public interface ServletContextInitializer {
    void onStartup(ServletContext var1) throws ServletException;
}

 1 @Override
 2 protected void onRefresh() {
 3     super.onRefresh();
 4     try {
 5         //核心方法：会获取嵌入式的Servlet容器工厂，并通过工厂来获取Servlet容器
 6         createEmbeddedServletContainer();
 7     }
 8     catch (Throwable ex) {
 9         throw new ApplicationContextException("Unable to start embedded container", ex);
10     }
11 }
12 
13 private void createEmbeddedServletContainer() {
14     EmbeddedServletContainer localContainer = this.embeddedServletContainer;
15     ServletContext localServletContext = getServletContext();
16     if (localContainer == null && localServletContext == null) {
17         //先获取嵌入式Servlet容器工厂
18         EmbeddedServletContainerFactory containerFactory = getEmbeddedServletContainerFactory();
19         //根据容器工厂来获取对应的嵌入式Servlet容器
20         this.embeddedServletContainer = containerFactory.getEmbeddedServletContainer(getSelfInitializer());
21     }
22     else if (localServletContext != null) {
23         try {
24             getSelfInitializer().onStartup(localServletContext);
25         }
26         catch (ServletException ex) {
27             throw new ApplicationContextException("Cannot initialize servlet context",ex);
28         }
29     }
30     initPropertySources();
31 }

1 private ServletContextInitializer getSelfInitializer() {
2     //只是创建了一个ServletContextInitializer实例返回
3     //所以Servlet容器启动的时候，会调用这个对象的onStartup方法
4     return new ServletContextInitializer() {
5         public void onStartup(ServletContext servletContext) throws ServletException {
6             EmbeddedWebApplicationContext.this.selfInitialize(servletContext);
7         }
8     };
9 }

 1 private void selfInitialize(ServletContext servletContext) throws ServletException {
 2     prepareWebApplicationContext(servletContext);
 3     ConfigurableListableBeanFactory beanFactory = getBeanFactory();
 4     ExistingWebApplicationScopes existingScopes = new ExistingWebApplicationScopes(beanFactory);
 5     WebApplicationContextUtils.registerWebApplicationScopes(beanFactory,getServletContext());
 6     existingScopes.restore();
 7     WebApplicationContextUtils.registerEnvironmentBeans(beanFactory,getServletContext());
 8     //这里便是获取所有的 ServletContextInitializer 实现类，会获取所有的注册组件
 9     for (ServletContextInitializer beans : getServletContextInitializerBeans()) {
10         //执行所有ServletContextInitializer的onStartup方法
11         beans.onStartup(servletContext);
12     }
13 }

protected Collection<ServletContextInitializer> getServletContextInitializerBeans() {
    return new ServletContextInitializerBeans(getBeanFactory());
}

 1 public class ServletContextInitializerBeans extends AbstractCollection<ServletContextInitializer> {
 2     private final MultiValueMap<Class<?>, ServletContextInitializer> initializers = new LinkedMultiValueMap();
 3     //存放所有的ServletContextInitializer
 4     private List<ServletContextInitializer> sortedList;
 5 
 6     public ServletContextInitializerBeans(ListableBeanFactory beanFactory) {
 7         //执行addServletContextInitializerBeans
 8         this.addServletContextInitializerBeans(beanFactory);
 9         //执行addAdaptableBeans
10         this.addAdaptableBeans(beanFactory);
11         List<ServletContextInitializer> sortedInitializers = new ArrayList();
12         Iterator var3 = this.initializers.entrySet().iterator();
13 
14         while(var3.hasNext()) {
15             Entry<?, List<ServletContextInitializer>> entry = (Entry)var3.next();
16             AnnotationAwareOrderComparator.sort((List)entry.getValue());
17             sortedInitializers.addAll((Collection)entry.getValue());
18         }
19         this.sortedList = Collections.unmodifiableList(sortedInitializers);
20     }
21 
22     private void addServletContextInitializerBeans(ListableBeanFactory beanFactory) {
23         Iterator var2 = this.getOrderedBeansOfType(beanFactory, ServletContextInitializer.class).iterator();
24 
25         while(var2.hasNext()) {
26             Entry<String, ServletContextInitializer> initializerBean = (Entry)var2.next();
27             this.addServletContextInitializerBean((String)initializerBean.getKey(), (ServletContextInitializer)initializerBean.getValue(), beanFactory);
28         }
29 
30     }
31 
32     private void addServletContextInitializerBean(String beanName, ServletContextInitializer initializer, ListableBeanFactory beanFactory) {
33         if (initializer instanceof ServletRegistrationBean) {
34             Servlet source = ((ServletRegistrationBean)initializer).getServlet();
35             this.addServletContextInitializerBean(Servlet.class, beanName, initializer, beanFactory, source);
36         } else if (initializer instanceof FilterRegistrationBean) {
37             Filter source = ((FilterRegistrationBean)initializer).getFilter();
38             this.addServletContextInitializerBean(Filter.class, beanName, initializer, beanFactory, source);
39         } else if (initializer instanceof DelegatingFilterProxyRegistrationBean) {
40             String source = ((DelegatingFilterProxyRegistrationBean)initializer).getTargetBeanName();
41             this.addServletContextInitializerBean(Filter.class, beanName, initializer, beanFactory, source);
42         } else if (initializer instanceof ServletListenerRegistrationBean) {
43             EventListener source = ((ServletListenerRegistrationBean)initializer).getListener();
44             this.addServletContextInitializerBean(EventListener.class, beanName, initializer, beanFactory, source);
45         } else {
46             this.addServletContextInitializerBean(ServletContextInitializer.class, beanName, initializer, beanFactory, initializer);
47         }
48 
49     }
50 
51     private void addServletContextInitializerBean(Class<?> type, String beanName, ServletContextInitializer initializer, ListableBeanFactory beanFactory, Object source) {
52         this.initializers.add(type, initializer);
53         if (source != null) {
54             this.seen.add(source);
55         }
56 
57         if (logger.isDebugEnabled()) {
58             String resourceDescription = this.getResourceDescription(beanName, beanFactory);
59             int order = this.getOrder(initializer);
60             logger.debug("Added existing " + type.getSimpleName() + " initializer bean ''" + beanName + "''; order=" + order + ", resource=" + resourceDescription);
61         }
62 
63     }
64 
65     private void addAdaptableBeans(ListableBeanFactory beanFactory) {
66         MultipartConfigElement multipartConfig = this.getMultipartConfig(beanFactory);
67         this.addAsRegistrationBean(beanFactory, Servlet.class, new ServletContextInitializerBeans.ServletRegistrationBeanAdapter(multipartConfig));
68         this.addAsRegistrationBean(beanFactory, Filter.class, new ServletContextInitializerBeans.FilterRegistrationBeanAdapter(null));
69         Iterator var3 = ServletListenerRegistrationBean.getSupportedTypes().iterator();
70 
71         while(var3.hasNext()) {
72             Class<?> listenerType = (Class)var3.next();
73             this.addAsRegistrationBean(beanFactory, EventListener.class, listenerType, new ServletContextInitializerBeans.ServletListenerRegistrationBeanAdapter(null));
74         }
75 
76     }
77     
78     public Iterator<ServletContextInitializer> iterator() {
79         //返回所有的ServletContextInitializer
80         return this.sortedList.iterator();
81     }
82 
83     //略...
84 }

1 private void addServletContextInitializerBeans(ListableBeanFactory beanFactory) {
2     //从Spring容器中获取所有ServletContextInitializer.class 类型的Bean
3     for (Entry<String, ServletContextInitializer> initializerBean : getOrderedBeansOfType(beanFactory, ServletContextInitializer.class)) {
4         //添加到具体的集合中
5         addServletContextInitializerBean(initializerBean.getKey(),initializerBean.getValue(), beanFactory);
6     }
7 }

 1 private void addServletContextInitializerBean(String beanName, ServletContextInitializer initializer, ListableBeanFactory beanFactory) {
 2     //判断ServletRegistrationBean类型
 3     if (initializer instanceof ServletRegistrationBean) {
 4         Servlet source = ((ServletRegistrationBean)initializer).getServlet();
 5         //将ServletRegistrationBean加入到集合中
 6         this.addServletContextInitializerBean(Servlet.class, beanName, initializer, beanFactory, source);
 7     //判断FilterRegistrationBean类型
 8     } else if (initializer instanceof FilterRegistrationBean) {
 9         Filter source = ((FilterRegistrationBean)initializer).getFilter();
10         //将ServletRegistrationBean加入到集合中
11         this.addServletContextInitializerBean(Filter.class, beanName, initializer, beanFactory, source);
12     } else if (initializer instanceof DelegatingFilterProxyRegistrationBean) {
13         String source = ((DelegatingFilterProxyRegistrationBean)initializer).getTargetBeanName();
14         this.addServletContextInitializerBean(Filter.class, beanName, initializer, beanFactory, source);
15     } else if (initializer instanceof ServletListenerRegistrationBean) {
16         EventListener source = ((ServletListenerRegistrationBean)initializer).getListener();
17         this.addServletContextInitializerBean(EventListener.class, beanName, initializer, beanFactory, source);
18     } else {
19         this.addServletContextInitializerBean(ServletContextInitializer.class, beanName, initializer, beanFactory, initializer);
20     }
21 
22 }
23 
24 private void addServletContextInitializerBean(Class<?> type, String beanName, 
25                             ServletContextInitializer initializer, ListableBeanFactory beanFactory, Object source) {
26     //加入到initializers中
27     this.initializers.add(type, initializer);
28 }

 1 private void addAdaptableBeans(ListableBeanFactory beanFactory) {
 2     //从beanFactory获取所有Servlet.class和Filter.class类型的Bean，并封装成RegistrationBean对象，加入到集合中
 3     this.addAsRegistrationBean(beanFactory, Servlet.class, new ServletContextInitializerBeans.ServletRegistrationBeanAdapter(multipartConfig));
 4     this.addAsRegistrationBean(beanFactory, Filter.class, new ServletContextInitializerBeans.FilterRegistrationBeanAdapter(null));
 5 }
 6 
 7 private <T, B extends T> void addAsRegistrationBean(ListableBeanFactory beanFactory, Class<T> type, Class<B> beanType, ServletContextInitializerBeans.RegistrationBeanAdapter<T> adapter) {
 8     //从Spring容器中获取所有的Servlet.class和Filter.class类型的Bean
 9     List<Entry<String, B>> beans = this.getOrderedBeansOfType(beanFactory, beanType, this.seen);
10     Iterator var6 = beans.iterator();
11 
12     while(var6.hasNext()) {
13         Entry<String, B> bean = (Entry)var6.next();
14         if (this.seen.add(bean.getValue())) {
15             int order = this.getOrder(bean.getValue());
16             String beanName = (String)bean.getKey();
17             //创建Servlet.class和Filter.class包装成RegistrationBean对象
18             RegistrationBean registration = adapter.createRegistrationBean(beanName, bean.getValue(), beans.size());
19             registration.setName(beanName);
20             registration.setOrder(order);
21             this.initializers.add(type, registration);
22             if (logger.isDebugEnabled()) {
23                 logger.debug("Created " + type.getSimpleName() + " initializer for bean ''" + beanName + "''; order=" + order + ", resource=" + this.getResourceDescription(beanName, beanFactory));
24             }
25         }
26     }
27 
28 }

private static class ServletRegistrationBeanAdapter implements ServletContextInitializerBeans.RegistrationBeanAdapter<Servlet> {
    private final MultipartConfigElement multipartConfig;

    ServletRegistrationBeanAdapter(MultipartConfigElement multipartConfig) {
        this.multipartConfig = multipartConfig;
    }

    public RegistrationBean createRegistrationBean(String name, Servlet source, int totalNumberOfSourceBeans) {
        String url = totalNumberOfSourceBeans == 1 ? "/" : "/" + name + "/";
        if (name.equals("dispatcherServlet")) {
            url = "/";
        }
        //还是将Servlet.class实例封装成ServletRegistrationBean对象
        //这和我们自己创建ServletRegistrationBean对象是一模一样的
        ServletRegistrationBean bean = new ServletRegistrationBean(source, new String[]{url});
        bean.setMultipartConfig(this.multipartConfig);
        return bean;
    }
}

private static class FilterRegistrationBeanAdapter implements ServletContextInitializerBeans.RegistrationBeanAdapter<Filter> {
    private FilterRegistrationBeanAdapter() {
    }

    public RegistrationBean createRegistrationBean(String name, Filter source, int totalNumberOfSourceBeans) {
        //Filter.class实例封装成FilterRegistrationBean对象
        return new FilterRegistrationBean(source, new ServletRegistrationBean[0]);
    }
}

public class ServletRegistrationBean extends RegistrationBean {
    private static final Log logger = LogFactory.getLog(ServletRegistrationBean.class);
    private static final String[] DEFAULT_MAPPINGS = new String[]{"/*"};
    private Servlet servlet;
    
    public void onStartup(ServletContext servletContext) throws ServletException {
        Assert.notNull(this.servlet, "Servlet must not be null");
        String name = this.getServletName();
        //调用ServletContext的addServlet
        Dynamic added = servletContext.addServlet(name, this.servlet);
    }
    
    //略...
}

private javax.servlet.ServletRegistration.Dynamic addServlet(String servletName, String servletClass, Servlet servlet, Map<String, String> initParams) throws IllegalStateException {
    if (servletName != null && !servletName.equals("")) {
        if (!this.context.getState().equals(LifecycleState.STARTING_PREP)) {
            throw new IllegalStateException(sm.getString("applicationContext.addServlet.ise", new Object[]{this.getContextPath()}));
        } else {
            Wrapper wrapper = (Wrapper)this.context.findChild(servletName);
            if (wrapper == null) {
                wrapper = this.context.createWrapper();
                wrapper.setName(servletName);
                this.context.addChild(wrapper);
            } else if (wrapper.getName() != null && wrapper.getServletClass() != null) {
                if (!wrapper.isOverridable()) {
                    return null;
                }

                wrapper.setOverridable(false);
            }

            if (servlet == null) {
                wrapper.setServletClass(servletClass);
            } else {
                wrapper.setServletClass(servlet.getClass().getName());
                wrapper.setServlet(servlet);
            }

            if (initParams != null) {
                Iterator i$ = initParams.entrySet().iterator();

                while(i$.hasNext()) {
                    Entry<String, String> initParam = (Entry)i$.next();
                    wrapper.addInitParameter((String)initParam.getKey(), (String)initParam.getValue());
                }
            }

            return this.context.dynamicServletAdded(wrapper);
        }
    } else {
        throw new IllegalArgumentException(sm.getString("applicationContext.invalidServletName", new Object[]{servletName}));
    }
}

public void onStartup(ServletContext servletContext) throws ServletException {
    Filter filter = this.getFilter();
    Assert.notNull(filter, "Filter must not be null");
    String name = this.getOrDeduceName(filter);
    //调用ServletContext的addFilter
    Dynamic added = servletContext.addFilter(name, filter);
}