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1. 主要类¶

DispatcherServlet
WebApplicationContext
RequestContextUtils

preHandle postHandle afterCompletion

可以对 response 进行干预 ResponseBodyAdvice RequestMappingHandlerAdapter

HandlerExceptionResolver 异常处理程序的 Resolver * SimpleMappingExceptionResolver * DefaultHandlerExceptionResolver * ResponseStatusExceptionResolver * ExceptionHandlerExceptionResolver

FormattingConversionServiceFactoryBean

View Resovler

LocalValidatorFactoryBean

能够用于 MVC 配置的机制有 * 实现 WebMvcConfigurer 接口，可以添加 * addFormatters * addInterceptors * addResourceHandlers * addCorsMappings * addViewControllers * addArgumentResolvers * addReturnValueHandlers * 通过 @InitBinder 注解

上边的 addXXX 中有个 yyyRegistry 的概念

2. Context Hierarchy¶

3. web.xml 中可以配置的参数¶

3.1 MVC Config¶

都可以配置哪些内容

使能 MVC 配置
MVC Config API
Type Conversion
Validation
Interceptors
Content Types
Message Converters
View Controllers
View Resolvers
Static Resources
Default Servlet
Path Matching
Advanced Java Config
Advance XML Config

3.1.1 配置静态资源¶

@Configuration
@EnableWebMvc
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/resources/**")
                .addResourceLocations("/public", "classpath:/static/")
                .setCacheControl(CacheControl.maxAge(Duration.ofDays(365)));
    }
}

@Configuration
@EnableWebMvc
public class WebConfig {
}

@Configuration
@EnableWebMvc
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void addFormatters(FormatterRegistry registry) {
        DateTimeFormatterRegistrar registrar = new DateTimeFormatterRegistrar();
        registrar.setUseIsoFormat(true);
        registrar.registerFormatters(registry);
    }
}

3.1.2 错误处理¶

错误处理调用链
默认错误处理页

3.1.3 视图(View) 相关¶

核心类 * ViewResolver * View

ViewResolver * AbstractCachingViewResolver * UrlBasedViewResolver * InternalResourceViewResolver * FreeMarkerViewResolver * ContentNegotiatingViewResolver * BeanNameViewResolver

View 也可以多个组成 chain view resolvers

3.1.3.1 重定向*(Redirecting)¶

前缀 redirect:，对应的 View 为 RedirectView

3.1.3.2 (转发)Forwarding¶

前缀 forward:,

UrlBasedViewResolver RequestDispatcher.forward()

3.1.3.3 内容协商¶

3.1.3.4 本地化¶

RequestContext.getLocale()

org.springframework.web.servlet.i18n

可以根据以下纬度进行 locale 的解析 - Time Zone - Header Resolver - Cookie Resolver - Session Resolver - Locale Interceptor

3.1.3.5 主题¶

包: org.springframework.ui.context.ThemeSourc

ThemeResolver * FixedThemeResolver * SessionThemeResolver * CookieThemeResolver

org.springframework.ui.context.support.ResourceBundleThemeSource

3.1.3.6 Multipart Resolver¶

包 org.springframework.web.multipart

MultipartResolver * CommonsMultipartResolver * StandardServletMultipartResolver MultipartHttpServletRequest

3.2 CORS 跨域处理¶

每个 HandlerMapping 均可以配置自己的 CorsConfiguration；但通常有一个全局的 CORS 配置即可

@Configuration
@EnableWebMvc
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void addCorsMappings(CorsRegistry registry) {

        registry.addMapping("/api/**")
            .allowedOrigins("https://domain2.com")
            .allowedMethods("PUT", "DELETE")
            .allowedHeaders("header1", "header2", "header3")
            .exposedHeaders("header1", "header2")
            .allowCredentials(true).maxAge(3600);

        // Add more mappings...
    }
}

3.2.1 支持条件定义接口¶

如下示例: 判断请求参数中是否包含 https://xxx.com/pets/1234?myParam=myValue

@GetMapping(path = "/pets/{petId}", params = "myParam=myValue") 
public void findPet(@PathVariable String petId) {
    // ...
}

如下示例，判断是否 HTTP header 包含 myHeader: myValue

@GetMapping(path = "/pets", headers = "myHeader=myValue") 
public void findPet(@PathVariable String petId) {
    // ...
}

3.2.1.1 @RequestParam 不是必须的¶

Note that use of @RequestParam is optional (for example, to set its attributes). By default, any argument that is a simple value type (as determined by BeanUtils#isSimpleProperty) and is not resolved by any other argument resolver, is treated as if it were annotated with @RequestParam.

3.2.1.2 @RequestHeader 可以作用到通用集合类型上 Map, MultiValueMap, or HttpHeaders¶

When an @RequestHeader annotation is used on a Map, MultiValueMap, or HttpHeaders argument, the map is populated with all header values.

3.2.2 Data binding 和 Type conversion 的区别¶

@ModelAttribute 可以作用到方法上、参数上
@ModelAttribute(binding=false) 可以通过 binding=false 指定不进行参数绑定
可以通过 Valid 指定对参数是否进行校验

ResponseEntity && RequestEntity 表示 HTTP 响应、请求的完整实体，包括请求头、方法、body 等

3.3 1.10 视图技术¶

3.4 1.11 MVC 配置¶

@Configuration
@EnableWebMvc
public class WebConfiguration implements WebMvcConfigurer {

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder()
                .indentOutput(true)
                .dateFormat(new SimpleDateFormat("yyyy-MM-dd"))
                .modulesToInstall(new ParameterNamesModule());
        converters.add(new MappingJackson2HttpMessageConverter(builder.build()));
        converters.add(new MappingJackson2XmlHttpMessageConverter(builder.createXmlMapper(true).build()));
    }
}

4. 2. REST 客户端 (REST Client)¶

4.1 2.1 RestTemplate¶

从 Spring 5.0 开始， RestTempalte 进入维护模式，后续可以使用 WebClient 提供的更加现代，且支持同步、异步、流场景的 API

5. 3. 测试(Testing)¶

Servlet API Mocks
TestContext Framework
Spring MVC Test
Client-side REST
WebTestClient

6. 4. Websockets¶

6.1 主要类¶

@EnableWebSocket 开启 Websocket
WebSocketHttpRequestHandler
TextWebSocketHandler
BinaryWebSocketHandler
ConcurrentWebSocketSessionDecorator
WebSocketConfigurer
WebSocketHandlerRegistry
HandshakeInterceptor

import org.springframework.web.socket.config.annotation.EnableWebSocket;
import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;

@Configuration
@EnableWebSocket
public class WebSocketConfig implements WebSocketConfigurer {

    @Override
    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
        registry.addHandler(myHandler(), "/myHandler");
    }

    @Bean
    public WebSocketHandler myHandler() {
        return new MyHandler();
    }

}