/**
 * 主程序类
 * @SpringBootApplication：这是一个SpringBoot应用
 */
@SpringBootApplication
public class MainApplication {
    public static void main(String[] args) {
        SpringApplication.run(MainApplication.class,args);
    }
}

@RestController
public class HelloController {

    @RequestMapping("/hello")
    public String handle01(){
        return "Hello, Spring Boot 2!";
    }

}

@SpringBootApplication
等同于
@SpringBootConfiguration
@EnableAutoConfiguration
@ComponentScan("com.atguigu.boot")

//###########################Configuration使用示例#######################################
/**
 * 1、配置类里面使用@Bean标注在方法上给容器注册组件，默认也是单实例的
 * 2、配置类本身也是组件
 * 3、proxyBeanMethods：代理bean的方法
 *      Full(proxyBeanMethods = true)、【保证每个@Bean方法被调用多少次返回的组件都是单实例的】
 *      Lite(proxyBeanMethods = false)【每个@Bean方法被调用多少次返回的组件都是新创建的】
 *      组件依赖必须使用Full模式默认。其他默认是否Lite模式
 *
 *
 *
 */
@Configuration(proxyBeanMethods = false) //告诉SpringBoot这是一个配置类 == 配置文件
public class MyConfig {

    /**
     * Full:外部无论对配置类中的这个组件注册方法调用多少次获取的都是之前注册容器中的单实例对象
     * @return
     */
    @Bean //给容器中添加组件。以方法名作为组件的id。返回类型就是组件类型。返回的值，就是组件在容器中的实例
    public User user01(){
        User zhangsan = new User("zhangsan", 18);
        //user组件依赖了Pet组件
        zhangsan.setPet(tomcatPet());
        return zhangsan;
    }

    @Bean("tom")
    public Pet tomcatPet(){
        return new Pet("tomcat");
    }
}
//#############################@Configuration测试代码如下##############################
@SpringBootConfiguration
@EnableAutoConfiguration
@ComponentScan("com.atguigu.boot")
public class MainApplication {

    public static void main(String[] args) {
        //1、返回我们IOC容器
        ConfigurableApplicationContext run = SpringApplication.run(MainApplication.class, args);

        //2、查看容器里面的组件
        String[] names = run.getBeanDefinitionNames();
        for (String name : names) {
            System.out.println(name);
        }

        //3、从容器中获取组件

        Pet tom01 = run.getBean("tom", Pet.class);

        Pet tom02 = run.getBean("tom", Pet.class);

        System.out.println("组件："+(tom01 == tom02));


        //4、com.atguigu.boot.config.MyConfig$$EnhancerBySpringCGLIB$$51f1e1ca@1654a892
        MyConfig bean = run.getBean(MyConfig.class);
        System.out.println(bean);

        //如果@Configuration(proxyBeanMethods = true)代理对象调用方法。SpringBoot总会检查这个组件是否在容器中有。
        //保持组件单实例
        User user = bean.user01();
        User user1 = bean.user01();
        System.out.println(user == user1);


        User user01 = run.getBean("user01", User.class);
        Pet tom = run.getBean("tom", Pet.class);

        System.out.println("用户的宠物："+(user01.getPet() == tom));

    }
}

/* * 4、@Import({User.class, DBHelper.class})
 *      给容器中自动创建出这两个类型的组件、默认组件的名字就是全类名
 *
 *
 *
 */
@Import({User.class, DBHelper.class})
@Configuration(proxyBeanMethods = false) //告诉SpringBoot这是一个配置类 == 配置文件
public class MyConfig {
}

//===================测试条件装配==========================
@Configuration(proxyBeanMethods = false) //告诉SpringBoot这是一个配置类 == 配置文件
//@ConditionalOnBean(name = "tom")
@ConditionalOnMissingBean(name = "tom")
public class MyConfig {

    /**
     * Full:外部无论对配置类中的这个组件注册方法调用多少次获取的都是之前注册容器中的单实例对象
     * @return
     */

    @Bean //给容器中添加组件。以方法名作为组件的id。返回类型就是组件类型。返回的值，就是组件在容器中的实例
    public User user01(){
        User zhangsan = new User("zhangsan", 18);
        //user组件依赖了Pet组件
        zhangsan.setPet(tomcatPet());
        return zhangsan;
    }

    @Bean("tom22")
    public Pet tomcatPet(){
        return new Pet("tomcat");
    }
}

public static void main(String[] args) {
    //1、返回我们IOC容器
    ConfigurableApplicationContext run = SpringApplication.run(MainApplication.class, args);

    //2、查看容器里面的组件
    String[] names = run.getBeanDefinitionNames();
    for (String name : names) {
        System.out.println(name);
    }

    boolean tom = run.containsBean("tom");
    System.out.println("容器中Tom组件："+tom);

    boolean user01 = run.containsBean("user01");
    System.out.println("容器中user01组件："+user01);

    boolean tom22 = run.containsBean("tom22");
    System.out.println("容器中tom22组件："+tom22);

}

@ImportResource("classpath:beans.xml")
public class MyConfig {}

======================测试=================
    boolean haha = run.containsBean("haha");
    boolean hehe = run.containsBean("hehe");
    System.out.println("haha："+haha);//true
    System.out.println("hehe："+hehe);//true

public class getProperties {
    public static void main(String[] args) throws FileNotFoundException, IOException {
        Properties pps = new Properties();
        pps.load(new FileInputStream("a.properties"));
        Enumeration enum1 = pps.propertyNames();//得到配置文件的名字
        while(enum1.hasMoreElements()) {
            String strKey = (String) enum1.nextElement();
            String strValue = pps.getProperty(strKey);
            System.out.println(strKey + "=" + strValue);
            //封装到JavaBean。
        }
    }
}

/**
 * 只有在容器中的组件，才会拥有SpringBoot提供的强大功能
 */
@Component
@ConfigurationProperties(prefix = "mycar")
public class Car {

    private String brand;
    private Integer price;

    public String getBrand() {
        return brand;
    }

    public void setBrand(String brand) {
        this.brand = brand;
    }

    public Integer getPrice() {
        return price;
    }

    public void setPrice(Integer price) {
        this.price = price;
    }

    @Override
    public String toString() {
        return "Car{" +
            "brand='" + brand + '\'' +
            ", price=" + price +
            '}';
    }
}

@EnableConfigurationProperties(Car.class)
//1、开启Car自动绑定功能
//2、把Car这个组件自动注册到容器中
public class MyConfig {}

@Component 
@ConfigurationProperties(prefix = "mycar")
public class Car{}

@SpringBootConfiguration
@EnableAutoConfiguration
@ComponentScan(excludeFilters = { @Filter(type = FilterType.CUSTOM, classes = TypeExcludeFilter.class),
		@Filter(type = FilterType.CUSTOM, classes = AutoConfigurationExcludeFilter.class) })
public @interface SpringBootApplication{}

@AutoConfigurationPackage
@Import(AutoConfigurationImportSelector.class)
public @interface EnableAutoConfiguration {}

@Import(AutoConfigurationPackages.Registrar.class)  //给容器中导入一个组件
public @interface AutoConfigurationPackage {}

//利用Registrar给容器中导入一系列组件
//将指定的一个包下的所有组件导入进来？MainApplication 所在包下。

@Bean
@ConditionalOnBean(MultipartResolver.class)  //容器中有这个类型组件
@ConditionalOnMissingBean(name = DispatcherServlet.MULTIPART_RESOLVER_BEAN_NAME) //容器中没有这个名字 multipartResolver 的组件
public MultipartResolver multipartResolver(MultipartResolver resolver) {
    //给@Bean标注的方法传入了对象参数，这个参数的值就会从容器中找。
    //SpringMVC multipartResolver。防止有些用户配置的文件上传解析器不符合规范
    // Detect if the user has created a MultipartResolver but named it incorrectly
    return resolver;
}
给容器中加入了文件上传解析器；

@Bean
@ConditionalOnMissingBean //没有这个组件 再注册
public CharacterEncodingFilter characterEncodingFilter() {
}

//=============================简化JavaBean开发===================================
@NoArgsConstructor
@AllArgsConstructor
@Data
//@ToString
//@EqualsAndHashCode
public class User {
    private String name;
    private Integer age;
    private Pet pet;
}

//==============================简化日志开发===================================
@Slf4j
@RestController
public class HelloController {
    @RequestMapping("/hello")
    public String handle01(@RequestParam("name") String name){
        log.info("请求进来了....");
        return "Hello, Spring Boot 2!"+"你好："+name;
    }
}

@Data
public class Person {
    private String userName;
    private Boolean boss;
    private Date birth;
    private Integer age;
    private Pet pet;
    private String[] interests;
    private List<String> animal;
    private Map<String, Object> score;
    private Set<Double> salarys;
    private Map<String, List<Pet>> allPets;
}

@Data
public class Pet {
    private String name;
    private Double weight;
}

@Configuration(proxyBeanMethods = false)
@ConditionalOnWebApplication(type = Type.SERVLET)
@ConditionalOnClass({ Servlet.class, DispatcherServlet.class, WebMvcConfigurer.class })
@ConditionalOnMissingBean(WebMvcConfigurationSupport.class)
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE + 10)
@AutoConfigureAfter({ DispatcherServletAutoConfiguration.class, TaskExecutionAutoConfiguration.class,
        ValidationAutoConfiguration.class })
public class WebMvcAutoConfiguration {}

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

//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;
}

@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));
    }
}

@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;
}

// 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/**
        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");
    }
}

//@RequestMapping(value = "/user",method = RequestMethod.GET)
@GetMapping("/user")
public String getUser(){
    return "GET-张三";
}

//@RequestMapping(value = "/user",method = RequestMethod.POST)
@PostMapping("/user")
public String saveUser(){
    return "POST-张三";
}


//@RequestMapping(value = "/user",method = RequestMethod.PUT)
@PutMapping("/user")
public String putUser(){
    return "PUT-张三";
}

//@RequestMapping(value = "/user",method = RequestMethod.DELETE)
@DeleteMapping("/user")
public String deleteUser(){
    return "DELETE-张三";
}

@Bean
@ConditionalOnMissingBean(HiddenHttpMethodFilter.class)
@ConditionalOnProperty(prefix = "spring.mvc.hiddenmethod.filter", name = "enabled", matchIfMissing = false)
public OrderedHiddenHttpMethodFilter hiddenHttpMethodFilter() {
    return new OrderedHiddenHttpMethodFilter();
}

//自定义filter
@Bean
public HiddenHttpMethodFilter hiddenHttpMethodFilter(){
    HiddenHttpMethodFilter methodFilter = new HiddenHttpMethodFilter();
    methodFilter.setMethodParam("_m");
    return methodFilter;
}

protected void doDispatch(HttpServletRequest request, HttpServletResponse response) throws Exception {
    HttpServletRequest processedRequest = request;
    HandlerExecutionChain mappedHandler = null;
    boolean multipartRequestParsed = false;

    WebAsyncManager asyncManager = WebAsyncUtils.getAsyncManager(request);

    try {
        ModelAndView mv = null;
        Exception dispatchException = null;

        try {
            processedRequest = checkMultipart(request);
            multipartRequestParsed = (processedRequest != request);

            // 找到当前请求使用哪个Handler（Controller的方法）处理
            mappedHandler = getHandler(processedRequest);

            //HandlerMapping：处理器映射。/xxx->>xxxx

protected HandlerExecutionChain getHandler(HttpServletRequest request) throws Exception {
    if (this.handlerMappings != null) {
        for (HandlerMapping mapping : this.handlerMappings) {
            HandlerExecutionChain handler = mapping.getHandler(request);
            if (handler != null) {
                return handler;
            }
        }
    }
    return null;
}

@RestController
public class ParameterTestController {

    //  car/2/owner/zhangsan
    @GetMapping("/car/{id}/owner/{username}")
    public Map<String,Object> getCar(@PathVariable("id") Integer id,
                                     @PathVariable("username") String name,
                                     @PathVariable Map<String,String> pv,
                                     @RequestHeader("User-Agent") String userAgent,
                                     @RequestHeader Map<String,String> header,
                                     
                                     @RequestParam("age") Integer age,
                                     @RequestParam("inters") List<String> inters,
                                     @RequestParam Map<String,String> params,
                                     @CookieValue("_ga") String _ga,
                                     @CookieValue("_ga") Cookie cookie){

        Map<String,Object> map = new HashMap<>();

        //        map.put("id",id);
        //        map.put("name",name);
        //        map.put("pv",pv);
        //        map.put("userAgent",userAgent);
        //        map.put("headers",header);
        map.put("age",age);
        map.put("inters",inters);
        map.put("params",params);
        map.put("_ga",_ga);
        System.out.println(cookie.getName()+"===>"+cookie.getValue());
        return map;
    }

    @PostMapping("/save")
    public Map postMethod(@RequestBody String content){
        Map<String,Object> map = new HashMap<>();
        map.put("content",content);
        return map;
    }

    //1、语法： 请求路径：/cars/sell;low=34;brand=byd,audi,yd
    //2、SpringBoot默认是禁用了矩阵变量的功能
    //      手动开启：原理。对于路径的处理。UrlPathHelper进行解析。
    //              removeSemicolonContent（移除分号内容）支持矩阵变量的
    			// urlPathHelper.setRemoveSemicolonContent(false);
    //3、矩阵变量必须有url路径变量才能被解析
    @GetMapping("/cars/{path}")
    public Map carsSell(@MatrixVariable("low") Integer low,
                        @MatrixVariable("brand") List<String> brand,
                        @PathVariable("path") String path){
        Map<String,Object> map = new HashMap<>();

        map.put("low",low);
        map.put("brand",brand);
        map.put("path",path);
        return map;
    }

    // /boss/1;age=20/2;age=10

    @GetMapping("/boss/{bossId}/{empId}")
    public Map boss(@MatrixVariable(value = "age",pathVar = "bossId") Integer bossAge,
                    @MatrixVariable(value = "age",pathVar = "empId") Integer empAge){
        Map<String,Object> map = new HashMap<>();

        map.put("bossAge",bossAge);
        map.put("empAge",empAge);
        return map;
    }
}

@Override
public boolean supportsParameter(MethodParameter parameter) {
    Class<?> paramType = parameter.getParameterType();
    return (WebRequest.class.isAssignableFrom(paramType) ||
            ServletRequest.class.isAssignableFrom(paramType) ||
            MultipartRequest.class.isAssignableFrom(paramType) ||
            HttpSession.class.isAssignableFrom(paramType) ||
            (pushBuilder != null && pushBuilder.isAssignableFrom(paramType)) ||
            Principal.class.isAssignableFrom(paramType) ||
            InputStream.class.isAssignableFrom(paramType) ||
            Reader.class.isAssignableFrom(paramType) ||
            HttpMethod.class == paramType ||
            Locale.class == paramType ||
            TimeZone.class == paramType ||
            ZoneId.class == paramType);
}

Map<String,Object> map,  Model model, HttpServletRequest request 
都是可以给request域中放数据，request.getAttribute();

/**
 *     姓名： <input name="userName"/> <br/>
 *     年龄： <input name="age"/> <br/>
 *     生日： <input name="birth"/> <br/>
 *     宠物姓名：<input name="pet.name"/><br/>
 *     宠物年龄：<input name="pet.age"/>
 */
@Data
public class Person {
    private String userName;
    private Integer age;
    private Date birth;
    private Pet pet;
}

@Data
public class Pet {
    private String name;
    private String age;
}
result

// Actually invoke the handler.
//DispatcherServlet -- doDispatch
mv = ha.handle(processedRequest, response, mappedHandler.getHandler());
mav = invokeHandlerMethod(request, response, handlerMethod); //执行目标方法


//ServletInvocableHandlerMethod
Object returnValue = invokeForRequest(webRequest, mavContainer, providedArgs);
//获取方法的参数值
Object[] args = getMethodArgumentValues(request, mavContainer, providedArgs);

//============InvocableHandlerMethod==========================
protected Object[] getMethodArgumentValues(NativeWebRequest request, @Nullable ModelAndViewContainer mavContainer,Object... providedArgs) throws Exception {

    MethodParameter[] parameters = getMethodParameters();
    if (ObjectUtils.isEmpty(parameters)) {
        return EMPTY_ARGS;
    }

    Object[] args = new Object[parameters.length];
    for (int i = 0; i < parameters.length; i++) {
        MethodParameter parameter = parameters[i];
        parameter.initParameterNameDiscovery(this.parameterNameDiscoverer);
        args[i] = findProvidedArgument(parameter, providedArgs);
        if (args[i] != null) {
            continue;
        }
        if (!this.resolvers.supportsParameter(parameter)) {
            throw new IllegalStateException(formatArgumentError(parameter, "No suitable resolver"));
        }
        try {
            args[i] = this.resolvers.resolveArgument(parameter, mavContainer, request, this.dataBinderFactory);
        }
        catch (Exception ex) {
            // Leave stack trace for later, exception may actually be resolved and handled...
            if (logger.isDebugEnabled()) {
                String exMsg = ex.getMessage();
                if (exMsg != null && !exMsg.contains(parameter.getExecutable().toGenericString())) {
                    logger.debug(formatArgumentError(parameter, exMsg));
                }
            }
            throw ex;
        }
    }
    return args;
}

@Nullable
private HandlerMethodArgumentResolver getArgumentResolver(MethodParameter parameter) {
    HandlerMethodArgumentResolver result = this.argumentResolverCache.get(parameter);
    if (result == null) {
        for (HandlerMethodArgumentResolver resolver : this.argumentResolvers) {
            if (resolver.supportsParameter(parameter)) {
                result = resolver;
                this.argumentResolverCache.put(parameter, result);
                break;
            }
        }
    }
    return result;
}

public static boolean isSimpleValueType(Class<?> type) {
    return (Void.class != type && void.class != type &&
            (ClassUtils.isPrimitiveOrWrapper(type) ||
             Enum.class.isAssignableFrom(type) ||
             CharSequence.class.isAssignableFrom(type) ||
             Number.class.isAssignableFrom(type) ||
             Date.class.isAssignableFrom(type) ||
             Temporal.class.isAssignableFrom(type) ||
             URI.class == type ||
             URL.class == type ||
             Locale.class == type ||
             Class.class == type));
}

@Override
@Nullable
public final Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
                                    NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {

    Assert.state(mavContainer != null, "ModelAttributeMethodProcessor requires ModelAndViewContainer");
    Assert.state(binderFactory != null, "ModelAttributeMethodProcessor requires WebDataBinderFactory");

    String name = ModelFactory.getNameForParameter(parameter);
    ModelAttribute ann = parameter.getParameterAnnotation(ModelAttribute.class);
    if (ann != null) {
        mavContainer.setBinding(name, ann.binding());
    }

    Object attribute = null;
    BindingResult bindingResult = null;

    if (mavContainer.containsAttribute(name)) {
        attribute = mavContainer.getModel().get(name);
    }
    else {
        // Create attribute instance
        try {
            attribute = createAttribute(name, parameter, binderFactory, webRequest);
        }
        catch (BindException ex) {
            if (isBindExceptionRequired(parameter)) {
                // No BindingResult parameter -> fail with BindException
                throw ex;
            }
            // Otherwise, expose null/empty value and associated BindingResult
            if (parameter.getParameterType() == Optional.class) {
                attribute = Optional.empty();
            }
            bindingResult = ex.getBindingResult();
        }
    }

    if (bindingResult == null) {
        // Bean property binding and validation;
        // skipped in case of binding failure on construction.
        WebDataBinder binder = binderFactory.createBinder(webRequest, attribute, name);
        if (binder.getTarget() != null) {
            if (!mavContainer.isBindingDisabled(name)) {
                bindRequestParameters(binder, webRequest);
            }
            validateIfApplicable(binder, parameter);
            if (binder.getBindingResult().hasErrors() && isBindExceptionRequired(binder, parameter)) {
                throw new BindException(binder.getBindingResult());
            }
        }
        // Value type adaptation, also covering java.util.Optional
        if (!parameter.getParameterType().isInstance(attribute)) {
            attribute = binder.convertIfNecessary(binder.getTarget(), parameter.getParameterType(), parameter);
        }
        bindingResult = binder.getBindingResult();
    }

    // Add resolved attribute and BindingResult at the end of the model
    Map<String, Object> bindingResultModel = bindingResult.getModel();
    mavContainer.removeAttributes(bindingResultModel);
    mavContainer.addAllAttributes(bindingResultModel);

    return attribute;
}

//1、WebMvcConfigurer定制化SpringMVC的功能
@Bean
public WebMvcConfigurer webMvcConfigurer(){
    return new WebMvcConfigurer() {
        @Override
        public void configurePathMatch(PathMatchConfigurer configurer) {
            UrlPathHelper urlPathHelper = new UrlPathHelper();
            // 不移除；后面的内容。矩阵变量功能就可以生效
            urlPathHelper.setRemoveSemicolonContent(false);
            configurer.setUrlPathHelper(urlPathHelper);
        }

        @Override
        public void addFormatters(FormatterRegistry registry) {
            registry.addConverter(new Converter<String, Pet>() {

                @Override
                public Pet convert(String source) {
                    // 啊猫,3
                    if(!StringUtils.isEmpty(source)){
                        Pet pet = new Pet();
                        String[] split = source.split(",");
                        pet.setName(split[0]);
                        pet.setAge(Integer.parseInt(split[1]));
                        return pet;
                    }
                    return null;
                }
            });
        }
    };
}

InternalResourceView：
    @Override
    protected void renderMergedOutputModel(
    Map<String, Object> model, HttpServletRequest request, HttpServletResponse response) throws Exception {

    // Expose the model object as request attributes.
    exposeModelAsRequestAttributes(model, request);

    // Expose helpers as request attributes, if any.
    exposeHelpers(request);

    // Determine the path for the request dispatcher.
    String dispatcherPath = prepareForRendering(request, response);

    // Obtain a RequestDispatcher for the target resource (typically a JSP).
    RequestDispatcher rd = getRequestDispatcher(request, dispatcherPath);
    if (rd == null) {
        throw new ServletException("Could not get RequestDispatcher for [" + getUrl() +
                                   "]: Check that the corresponding file exists within your web application archive!");
    }

    // If already included or response already committed, perform include, else forward.
    if (useInclude(request, response)) {
        response.setContentType(getContentType());
        if (logger.isDebugEnabled()) {
            logger.debug("Including [" + getUrl() + "]");
        }
        rd.include(request, response);
    }

    else {
        // Note: The forwarded resource is supposed to determine the content type itself.
        if (logger.isDebugEnabled()) {
            logger.debug("Forwarding to [" + getUrl() + "]");
        }
        rd.forward(request, response);
    }
}

//暴露模型作为请求域属性
// Expose the model object as request attributes.
exposeModelAsRequestAttributes(model, request);

protected void exposeModelAsRequestAttributes(Map<String, Object> model, HttpServletRequest request) throws Exception {

    //model中的所有数据遍历挨个放在请求域中
    model.forEach((name, value) -> {
        if (value != null) {
            request.setAttribute(name, value);
        }
        else {
            request.removeAttribute(name);
        }
    });
}

try {
    this.returnValueHandlers.handleReturnValue(
        returnValue, getReturnValueType(returnValue), mavContainer, webRequest);
}

@Override
public void handleReturnValue(@Nullable Object returnValue, MethodParameter returnType,
                              ModelAndViewContainer mavContainer, NativeWebRequest webRequest) throws Exception {

    HandlerMethodReturnValueHandler handler = selectHandler(returnValue, returnType);
    if (handler == null) {
        throw new IllegalArgumentException("Unknown return value type: " + returnType.getParameterType().getName());
    }
    handler.handleReturnValue(returnValue, returnType, mavContainer, webRequest);
}

//RequestResponseBodyMethodProcessor  	
@Override
public void handleReturnValue(@Nullable Object returnValue, MethodParameter returnType,
                              ModelAndViewContainer mavContainer, NativeWebRequest webRequest)
    throws IOException, HttpMediaTypeNotAcceptableException, HttpMessageNotWritableException {

    mavContainer.setRequestHandled(true);
    ServletServerHttpRequest inputMessage = createInputMessage(webRequest);
    ServletServerHttpResponse outputMessage = createOutputMessage(webRequest);

    // Try even with null return value. ResponseBodyAdvice could get involved.
    // 使用消息转换器进行写出操作
    writeWithMessageConverters(returnValue, returnType, inputMessage, outputMessage);
}

//WebMvcConfigurationSupport
    jackson2XmlPresent = ClassUtils.isPresent("com.fasterxml.jackson.dataformat.xml.XmlMapper", classLoader);

if (jackson2XmlPresent) {
    Jackson2ObjectMapperBuilder builder = Jackson2ObjectMapperBuilder.xml();
    if (this.applicationContext != null) {
        builder.applicationContext(this.applicationContext);
    }
    messageConverters.add(new MappingJackson2XmlHttpMessageConverter(builder.build()));
}

@Bean
public WebMvcConfigurer webMvcConfigurer(){
    return new WebMvcConfigurer() {
        @Override
        public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {

        }
    }
}