Springmvc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

 

一、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,

 控制器

控制器Controller在springboot的注解扫描范围内自动管理。

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

@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

二、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 

 三、springboot自动扩展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; } }

3.1 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");
}

}

3.2 注册格式化

 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); } }); }

3.3 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;

 3.4 拦截器注册

1.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"); } }

2. 拦截器注册

 

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