《开启微服务之旅：Spring Boot Web开发》（二）

1. 1. S pringboot 整合springmvc

++++https://docs.spring.io/spring-boot/docs/2.0.2.RELEASE/reference/htmlsingle/#boot-features-spring-mvc++++

学习springmvc和springboot的自动配置我们必须对springmvc的组件足够了解，起码知道怎么用。Springmvc的组件基本都被springboot来做了自动的配置。

1. 1. 1. S pringmvc 的自动解管理

中央转发器（DispatcherServlet）

控制器

视图解析器

静态资源访问

消息转换器

格式化

静态资源管理

1. 1. 1. 1. 中央 转发器

Xml无需配置

|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| <servlet > <servlet-name >chapter2</servlet-name > <servlet-class >org.springframework.web.servlet.DispatcherServlet</servlet-class > <load-on-startup >1</load-on-startup > </servlet > <servlet-mapping > <servlet-name >chapter2</servlet-name > <url-pattern >/</url-pattern > </servlet-mapping > |

中央转发器被springboot自动接管，不再需要我们在web.xml中配置，我们现在的项目也不是web项目，也不存在web.xml,

org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration, \

1. 1. 1. 1. 控制器

控制器Controller在springboot的注解扫描范围内自动管理。

1. 1. 1. 1. 视图 解析器 自动 管理

Inclusion of ContentNegotiatingViewResolver and BeanNameViewResolver beans.

ContentNegotiatingViewResolver：组合所有的视图解析器的；

曾经的配置文件无需再配

|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| <bean id ="de" class ="org.springframework.web.servlet.view.InternalResourceViewResolver" > <property name ="prefix" value ="/WEB-INF/jsp/" ></property > <property name ="suffix" value ="*.jsp" ></property > </bean > |

源码：

|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| public ContentNegotiatingViewResolver viewResolver(BeanFactory beanFactory) { ContentNegotiatingViewResolver resolver = new ContentNegotiatingViewResolver(); resolver.setContentNegotiationManager((ContentNegotiationManager)beanFactory.getBean(ContentNegotiationManager.class )); resolver.setOrder(-2147483648); return resolver; } |

当我们做文件上传的时候我们也会发现multipartResolver 是自动被配置好的

页面

|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| <form action= "/upload" method= "post" enctype= "multipart/form-data" > <input name= "pic" type= "file" > <input type= "submit" > </form > |

Controller

|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| @ResponseBody @RequestMapping("/upload" ) public String upload(@RequestParam("pic" )MultipartFile file, HttpServletRequest request){ String contentType = file.getContentType(); String fileName = file.getOriginalFilename(); /*System.out.println("fileName-->" + fileName); System.out.println("getContentType-->" + contentType);*/ //String filePath = request.getSession().getServletContext().getRealPath("imgupload/"); String filePath = "D:/imgup / " ; try { this .uploadFile (file.getBytes(), filePath, fileName); } catch (Exception e) { // TODO: handle exception } return "success" ; } public static void uploadFile(byte [] file, String filePath, String fileName) throws Exception { File targetFile = new File(filePath); if (!targetFile.exists()){ targetFile.mkdirs(); } FileOutputStream out = new FileOutputStream(filePath+fileName); out.write(file); out.flush(); out.close(); } |

文件上传大小可以通过配置来修改

打开application.properties, 默认限制是10MB，我们可以任意修改

1. 1. 1. 1. 静态 资源访问

参见4.2

1. 1. 1. 1. 消息 转换和 格式化

Springboot自动配置了消息转换器

格式化转换器的自动注册

时间类型我们可以在这里修改

在配置文件中指定好时间的模式我们就可以输入了

1. 1. 1. 1. 欢迎页面 的自动配置

Springboot自动指定resources下的index.html

1. 1. 1. Springboot扩展springmvc

在实际开发中springboot并非完全自动化，很多跟业务相关我们需要自己扩展，springboot给我提供了接口。

我们可以来通过实现WebMvcConfigurer接口来扩展

|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| public interface WebMvcConfigurer { default void configurePathMatch(PathMatchConfigurer configurer) { } default void configureContentNegotiation(ContentNegotiationConfigurer configurer) { } default void configureAsyncSupport(AsyncSupportConfigurer configurer) { } default void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) { } default void addFormatters(FormatterRegistry registry) { } default void addInterceptors(InterceptorRegistry registry) { } default void addResourceHandlers(ResourceHandlerRegistry registry) { } default void addCorsMappings(CorsRegistry registry) { } default void addViewControllers(ViewControllerRegistry registry) { } default void configureViewResolvers(ViewResolverRegistry registry) { } default void addArgumentResolvers(List<HandlerMethodArgumentResolver> resolvers) { } default void addReturnValueHandlers(List<HandlerMethodReturnValueHandler> handlers) { } default void configureMessageConverters(List<HttpMessageConverter<?>> converters) { } default void extendMessageConverters(List<HttpMessageConverter<?>> converters) { } default void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> resolvers) { } default void extendHandlerExceptionResolvers(List<HandlerExceptionResolver> resolvers) { } @Nullable default Validator getValidator() { return null ; } @Nullable default MessageCodesResolver getMessageCodesResolver() { return null ; } } |

1. 1. 1. 1. 在 容器中 注册视图 控制器 ( 请求转发 )

创建一个MyMVCCofnig实现WebMvcConfigurer接口，实现一下addViewControllers方法，我们完成通过/tx访问，转发到success.html的工作

|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| @Configuration public class MyMVCCofnig implements WebMvcConfigurer{ @Override public void addViewControllers(ViewControllerRegistry registry) { registry.addViewController("/tx" ).setViewName("success" ); } |

1. 1. 1. 1. 注册 格式化器

用来可以对请求过来的日期格式化的字符串来做定制化。当然通过application.properties配置也可以办到。

|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| @Override public void addFormatters(FormatterRegistry registry) { registry.addFormatter(new Formatter<Date>() { @Override public String print(Date date, Locale locale) { return null ; } @Override public Date parse(String s, Locale locale) throws ParseException { return new SimpleDateFormat("yyyy-MM-dd" ).parse(s); } }); } |

1. 1. 1. 1. 消息 转换器扩展 fastjson

在pom.xml中引入fastjson

|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| <dependency > <groupId >com.alibaba</groupId > <artifactId >fastjson</artifactId > <version >1.2.47</version > </dependency > |

配置消息转换器，添加fastjson

|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| @Override public void configureMessageConverters(List<HttpMessageConverter<?>> converters) { FastJsonHttpMessageConverter fc = new FastJsonHttpMessageConverter(); FastJsonConfig fastJsonConfig = new FastJsonConfig(); fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat ); fc.setFastJsonConfig(fastJsonConfig); converters.add(fc); } |

在实体类上可以继续控制

|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| public class User { private String username ; private String password ; private int age ; private int score ; private int gender ; @JSONField(format = "yyyy-MM-dd" ) private Date date ; |

1. 1. 1. 1. 拦截器注册
2. 创建拦截器

|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| public class MyInterceptor implements HandlerInterceptor { @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { System.out .println(" 前置拦截 " ); return true ; } @Override public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { System.out .println(" 后置拦截 " ); } @Override public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { System.out .println(" 最终拦截 " ); } } |

拦截器注册

|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| @Override public void addInterceptors(InterceptorRegistry registry) { registry.addInterceptor(new MyInterceptor()) .addPathPatterns("/**" ) .excludePathPatterns("/hello2" ); } |

1. 1. 配置嵌入式 服务器
      1. 如何定制和修改 Servlet 容器的相关配置；

修改和server有关的配置（ServerProperties）；

|---------------------------------------------------------------------------|
| server.port=8081 server.context‐path=/tx server.tomcat.uri‐encoding=UTF‐8 |

1. 1. 1. 注册 Servlet 三大组件【 Servlet 、 Filter 、 Listener 】

由于SpringBoot默认是以jar包的方式启动嵌入式的Servlet容器来启动SpringBoot的web应用，没有web.xml文件。

1.servlet

|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| //注册三大组件 @Bean public ServletRegistrationBean myServlet(){ ServletRegistrationBean registrationBean = new ServletRegistrationBean(new MyServlet(),"/myServlet"); return registrationBean; } |

2. FilterRegistrationBean

|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| @Bean public FilterRegistrationBean myFilter(){ FilterRegistrationBean registrationBean = new FilterRegistrationBean(); registrationBean.setFilter(new MyFilter()); registrationBean.setUrlPatterns(Arrays.asList("/hello","/myServlet")); return registrationBean; } |

3. ServletListenerRegistrationBean

|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| @Bean public ServletListenerRegistrationBean myListener(){ ServletListenerRegistrationBean<MyListener> registrationBean = new ServletListenerRegistrationBean<>(new MyListener()); return registrationBean; } |

SpringBoot帮我们自动SpringMVC的时候，自动的注册SpringMVC的前端控制器；DispatcherServlet；

DispatcherServletAutoConfiguration中：

|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| @Bean(name = DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME) @ConditionalOnBean(value = DispatcherServlet.class, name = DEFAULT_DISPATCHER_SERVLET_BEAN_NAME) public ServletRegistrationBean dispatcherServletRegistration( DispatcherServlet dispatcherServlet) { ServletRegistrationBean registration = new ServletRegistrationBean( dispatcherServlet, this.serverProperties.getServletMapping()); //默认拦截： / 所有请求；包静态资源，但是不拦截jsp请求； /*会拦截jsp //可以通过server.servletPath来修改SpringMVC前端控制器默认拦截的请求路径 registration.setName(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME); registration.setLoadOnStartup( this.webMvcProperties.getServlet().getLoadOnStartup()); if (this.multipartConfig != null) { registration.setMultipartConfig(this.multipartConfig); } return registration; } |