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太原高级seo主管_石家庄软件外包_如何做好一个品牌推广_开发一个app需要多少钱

2024/12/23 7:07:30 来源:https://blog.csdn.net/PacosonSWJTU/article/details/142606685  浏览:    关键词:太原高级seo主管_石家庄软件外包_如何做好一个品牌推广_开发一个app需要多少钱
太原高级seo主管_石家庄软件外包_如何做好一个品牌推广_开发一个app需要多少钱

文章目录

  • 【README】
  • 【1】HanderMapping-处理器映射容器
    • 【1.1】HanderMapping实现类
      • 【1.1.1】SimpleUrlHandlerMapping
  • 【2】Controller(二级控制器)
    • 【2.1】AbstractController抽象控制器(控制器基类)
  • 【3】ModelAndView(模型与视图)
    • 【3.1】ModelAndView中的视图信息
    • 【3.2】ModelAndView中的模型数据
  • 【4】ViewResolver视图解析器
    • 【4.1】可用的ViewResolver实现类
      • 【4.1.1】单一视图类型的视图解析器(以UrlBasedViewResolver为基类)
      • 【4.1.2】多视图类型的视图解析器
  • 【5】View视图
    • 【5.1】View实现原理
    • 【5.2】View实现类(基类AbstractView)
    • 【5.3】AbstractView的子类AbstractUrlBasedView
      • 【5.3.1】使用jsp技术的view
      • 【5.3.2】使用通用模版技术的view
      • 【5.3.3】面向二进制文档格式的View
      • 【5.3.4】重定向视图RedirectView
      • 【5.3.5】使用XSLT技术的View
    • 【5.4】自定义View实现

【README】

本文总结自《spring揭秘》,作者王福强,非常棒的一本书,墙裂推荐;

1)springmvc有5个主要组件:

  • HandlerMapping: 封装请求标识与二级控制器映射关系;
  • Controller:二级控制器;
  • ModelAndView:封装模型数据与视图;
  • ViewResovler:视图解析器;
  • View:视图;

2)DispatcherServlet使用上述5个组件处理web请求的流程(把它们串起来)

  • DispatcherServlet一级控制器根据请求标识(如URL)从HandlerMapping查找对应二级控制器Controller,并把请求转发给该Controller;
  • Controller处理完成后返回ModelAndView(模型数据+视图)给DispatcherServlet一级控制器;
  • DispatcherServlet一级控制器根据ModelAndView对象,通过视图解析器ViewResolver获取视图实例View;
  • DispatcherServlet一级控制器调用view.render()方法做实际的视图渲染;


【1】HanderMapping-处理器映射容器

1)HandlerMapping: 用于封装请求标识(如URL)与二级控制器Controller(处理器)间的映射关系; 它实际上是一个接口;

【HandlerMapping】

public interface HandlerMapping {String BEST_MATCHING_HANDLER_ATTRIBUTE = HandlerMapping.class.getName() + ".bestMatchingHandler";/** @deprecated */@DeprecatedString LOOKUP_PATH = HandlerMapping.class.getName() + ".lookupPath";String PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE = HandlerMapping.class.getName() + ".pathWithinHandlerMapping";String BEST_MATCHING_PATTERN_ATTRIBUTE = HandlerMapping.class.getName() + ".bestMatchingPattern";String INTROSPECT_TYPE_LEVEL_MAPPING = HandlerMapping.class.getName() + ".introspectTypeLevelMapping";String URI_TEMPLATE_VARIABLES_ATTRIBUTE = HandlerMapping.class.getName() + ".uriTemplateVariables";String MATRIX_VARIABLES_ATTRIBUTE = HandlerMapping.class.getName() + ".matrixVariables";String PRODUCIBLE_MEDIA_TYPES_ATTRIBUTE = HandlerMapping.class.getName() + ".producibleMediaTypes";default boolean usesPathPatterns() {return false;}@NullableHandlerExecutionChain getHandler(HttpServletRequest request) throws Exception;
}

【1.1】HanderMapping实现类

1)常用HanderMapping实现类列表:

  • BeanNameUrlHandlerMapping :bean名称与url处理器映射;即一级控制器DispatcherServlet查找BeanName与请求url路径相同的二级控制器, 并把请求转发给该二级控制器处理;
  • SimpleUrlHandlerMapping: 简单URL处理器映射; 相比BeanNameUrlHandlerMapping ,SimpleUrlHandlerMapping能够提供更多灵活匹配模式;


【1.1.1】SimpleUrlHandlerMapping

1)为什么有了BeanNameUrlHandlerMapping ,还需要 SimpleUrlHandlerMapping ?

2)SimpleUrlHandlerMapping作用

  • 可以配置web请求到具体二级控制器的映射;
  • 可以把一组或多组拥有相似特征的web请求映射给二级控制器;
<!-- SimpleUrlHandlerMapping: 可以配置web请求到具体二级控制器的映射, 可以把一组或多组拥有相似特征的web请求映射给二级控制器--><bean id="handlerMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping"><!-- 设置SimpleUrlHandlerMapping优先级为1,优先匹配,若有多个HandlerMapping时 --><property name="order" value="1" /><property name="mappings"><value>/userController.do=userController/bankCard*.do=bankCardController/bankCard/*.do=bankCardController</value></property></bean>

3)一级控制器DispatcherServlet可以有多个HandlerMapping, 请求匹配时,哪个HandlerMapping优先匹配,哪个最后匹配呢?

  • HandlerMapping的优先级规定遵循spring框架内一贯的Ordered接口所规定的语义;
  • HandlerMapping接口的实现类都实现了Ordered接口,在配置HandlerMapping时,只需要指定其 order属性即可;


【2】Controller(二级控制器)

1)Controller:是springmvc框架支持的用于处理具体web请求的处理器类型之一;

【Controller】二级控制器

@FunctionalInterface
public interface Controller {@NullableModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception;
}

2)当然,我们可以自行实现Controller接口,包括请求参数的抽取,请求编码的设定,session管理,国际化信息处理,异常处理等;

  • 但为了简化开发成本,这些Controller细节,springmvc已经有现成实现,我们复用即可;

3)总结起来:springmvc提供了一套封装Controller细节的实现类,如下。

在这里插入图片描述

4)Controller可以分为两类: 基于servletapi的没有封装细节的控制器, 封装处理细节的规范操作控制器;

  • 基于servletapi的自行处理细节的控制器,包括 AbstractController,MultiActionController :
    • 控制器处理细节逻辑包括:从HttpServletRequest获取参数, 然后参数验证,调用业务层逻辑,最终返回一个 ModelAndView ;特别的,还可以自行通过 HttpServletResponse 输出最终的视图;
  • 封装处理细节的规范操作控制器,BaseCommandController及子类; 封装的细节如下:
    • 自动抽取请求参数并绑定到 Command对象;
    • 提供统一的数据验证方式; BaseCommandController及子类可以接受 Validator进行数据验证,我们可以提供具体Validator实现;
    • 规范化表单请求的处理流程, 并且对简单的多页面表单请求处理提供支持;

显然: 使用规范操作控制器,可以复用springmvc封装好的处理细节或者自行实现部分细节,开发成本低;

【注意】本文使用的spring版本是6.1.10,本文发现6.1.10中有AbstractController,但没有MultiActionController, BaseCommandController及其子类,所以Controller二级控制器章节仅做了解

在这里插入图片描述



【2.1】AbstractController抽象控制器(控制器基类)

1)AbstractController是所有控制器基类,该类通过模版方法模式定义了控制器处理细节的主要步骤:

  • 管理当前Controller所支持的请求方法类型(GET/POST)
  • 管理页面的缓存设置, 即是否允许浏览器缓存当前页面;
  • 管理执行流程在会话上的同步;

我们需要做的是: 重写AbstractController#handleRequestInternal()模版方法,实现具体业务逻辑处理;

【AbstractController】

public abstract class AbstractController extends WebContentGenerator implements Controller {private boolean synchronizeOnSession;public AbstractController() {this(true);}public AbstractController(boolean restrictDefaultSupportedMethods) {super(restrictDefaultSupportedMethods);this.synchronizeOnSession = false;}public final void setSynchronizeOnSession(boolean synchronizeOnSession) {this.synchronizeOnSession = synchronizeOnSession;}public final boolean isSynchronizeOnSession() {return this.synchronizeOnSession;}@Nullablepublic ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception {if (HttpMethod.OPTIONS.matches(request.getMethod())) {response.setHeader("Allow", this.getAllowHeader());return null;} else {this.checkRequest(request);this.prepareResponse(response);if (this.synchronizeOnSession) {HttpSession session = request.getSession(false);if (session != null) {Object mutex = WebUtils.getSessionMutex(session);synchronized(mutex) {return this.handleRequestInternal(request, response);}}}return this.handleRequestInternal(request, response); // 处理请求内部逻辑}}@Nullableprotected abstract ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response) throws Exception;
}

【UserController】

public class UserController extends AbstractController {private UserAppService userAppService;@Overrideprotected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response) throws Exception {System.out.println("handleRequestInternal 被访问了");ModelAndView modelAndView = new ModelAndView("userListPage");modelAndView.addObject("userList", userAppService.listUser());return modelAndView;}public void setUserAppService(UserAppService userAppService) {this.userAppService = userAppService;}
}


【3】ModelAndView(模型与视图)

1)ModelAndView: 包含2部分信息,包括视图内容(逻辑视图名称或具体视图实例),模型数据;

2)ModelAndView实际上是一个数据对象:通过该对象,可以使得web请求处理逻辑与视图渲染解耦开;



【3.1】ModelAndView中的视图信息

1)ModelAndView可以以逻辑视图名的形式或者View视图实例的形式来保存视图信息;

【DispatcherServlet#render()】

protected void render(ModelAndView mv, HttpServletRequest request, HttpServletResponse response) throws Exception {Locale locale = this.localeResolver != null ? this.localeResolver.resolveLocale(request) : request.getLocale();response.setLocale(locale);String viewName = mv.getViewName();View view;if (viewName != null) { // 若ModelAndView中逻辑视图名存在,则通过逻辑视图名获取视图实例 view = this.resolveViewName(viewName, mv.getModelInternal(), locale, request);if (view == null) {String var10002 = mv.getViewName();throw new ServletException("Could not resolve view with name '" + var10002 + "' in servlet with name '" + this.getServletName() + "'");}} else { // 若逻辑视图名【不】存在,则直接通过 ModelAndView 获取视图实例 view = mv.getView(); if (view == null) {throw new ServletException("ModelAndView [" + mv + "] neither contains a view name nor a View object in servlet with name '" + this.getServletName() + "'");}}   // ...view.render(mv.getModelInternal(), request, response); // 获取视图实例后渲染 //...
}

2)由上述代码可知:

  • 若ModelAndView中逻辑视图名存在,则通过逻辑视图名获取视图实例
  • 若逻辑视图名【不】存在,则直接通过 ModelAndView 获取视图实例


【3.2】ModelAndView中的模型数据

1)ModelAndView通过 ModelMap来保存模型数据, 通过构造方法传入或实例方法添加的模型数据添加到这个ModelMap中;

2)ModelAndView封装模型数据的代码示例;

public class UserController extends AbstractController {private UserAppService userAppService;@Overrideprotected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response) throws Exception {System.out.println("handleRequestInternal 被访问了");ModelAndView modelAndView = new ModelAndView("userListPage");modelAndView.addObject("userList", userAppService.listUser());return modelAndView;}public void setUserAppService(UserAppService userAppService) {this.userAppService = userAppService;}
}

【ModelAndView】

public ModelAndView addObject(String attributeName, @Nullable Object attributeValue) {this.getModelMap().addAttribute(attributeName, attributeValue);return this;}
// 
public ModelMap getModelMap() {if (this.model == null) {this.model = new ModelMap();}return this.model;}
// ModelMap 定义
public class ModelMap extends LinkedHashMap<String, Object> {// ...
}


【4】ViewResolver视图解析器

1)视图解析器:通过ModelAndView中的逻辑视图名,为一级控制器DispatcherServlet返回一个视图实例;

【DispatcherServlet#resolveViewName()】

protected View resolveViewName(String viewName, @Nullable Map<String, Object> model, Locale locale, HttpServletRequest request) throws Exception {if (this.viewResolvers != null) {Iterator var5 = this.viewResolvers.iterator();while(var5.hasNext()) {ViewResolver viewResolver = (ViewResolver)var5.next();View view = viewResolver.resolveViewName(viewName, locale); // 视图解析器通过视图逻辑名获取视图实例 if (view != null) {return view;}}}return null;}

【BeanNameViewResolver】视图解析器具体实现

public View resolveViewName(String viewName, Locale locale) throws BeansException {ApplicationContext context = this.obtainApplicationContext();if (!context.containsBean(viewName)) {return null;} else if (!context.isTypeMatch(viewName, View.class)) {if (this.logger.isDebugEnabled()) {this.logger.debug("Found bean named '" + viewName + "' but it does not implement View");}return null;} else {return (View)context.getBean(viewName, View.class); // 实际上是从spring容器中根据视图名(或beanName)获取View实例对象 }
}

2)视图解析器接口 ViewResolver, 其常用实现类是BeanNameViewResolver,或者AbstractCachingViewResolver子类;

针对每次请求都重新实例化View可能影响性能,所以AbstractCachingViewResolver是对View做了缓存功能的视图解析器; 默认启用缓存功能;可以通过setCache(boolean)重新设置缓存开关;

【AbstractCachingViewResolver】

public void setCache(boolean cache) {this.cacheLimit = cache ? 1024 : 0;
}


【4.1】可用的ViewResolver实现类

1)springmvc提供的ViewResolver实现类分为2类:

  • 支持单一视图类型的视图解析器;
  • 支持多种视图类型的视图解析器;


【4.1.1】单一视图类型的视图解析器(以UrlBasedViewResolver为基类)

1)单一视图解析器:顾名思义,仅支持一种视图类型的视图解析; 基类是UrlBasedViewResolver;

2)UrlBasedViewResolver子类如下:

  • InternalResourceViewResolver :对应 InternalResourceView视图类型的解析,即处理jsp模型的视图;(默认视图解析器)
  • FreeMarkerViewResolver :对应 FreeMarker视图模版的解析;
  • XsltViewResolver:根据逻辑视图名查找并返回XsltView类型的View实例;

3)单一视图类型的视图解析器使用:

  • 使用prefix属性指定模版所在路径;
  • 使用suffix属性指定模版文件的后缀名;
  • 对应的视图解析器就可以根据 [prefix] + viewName(逻辑视图名) + [suffix] 拼接成的URL找到对应模版文件,并构造对应view实例返回;


【4.1.2】多视图类型的视图解析器

1)多视图类型的视图解析器:可以对多种视图类型的视图进行解析;

2)多视图类型的视图解析器有3个:ResourceBundleViewResolver, XmlViewResolver, BeanNameViewResolver ;

3)在dispatcher-servlet.xml可以注册多个视图解析器;(dispatcher-servlet.xml是一级控制器DispatcherServlet加载依赖组件时读取的xml配置文件,在web.xml中配置) ;

【dispatcher-servlet.xml】

<!-- 注册视图解析器bean到springweb容器(一级控制器DispatcherServlet的web容器WebApplicationContext) -->
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"><property name="prefix" value="/WEB-INF/jsp/" /><property name="suffix" value=".jsp" />
</bean><!-- 注册BeanNameViewResolver视图解析器到springweb容器(一级控制器DispatcherServlet的web容器WebApplicationContext) -->
<bean id="beanNameViewResolver" class="org.springframework.web.servlet.view.BeanNameViewResolver"><property name="order" value="1" />
</bean>

4)与可以配置多个HandlerMapping类似,dispatcher-servlet.xml也可以配置多个视图解析器;

  • 通过指定order属性,设置视图解析器优先级;
  • 若没有配置视图解析器或DispatcherServlet没有在当前的WebApplicationContext中找到任何ViewResolver定义,则默认使用 InternalResourceViewResolver 作为视图解析器; (建议把InternalResourceViewResolver 优先级设置最低,作为兜底)


【5】View视图

1)View视图:是springmvc中把视图渲染逻辑从DispatcherServlet解耦出来的关键组件; 通过实现View接口, 我们可以支持多种视图渲染技术;

2)视图渲染: 通过view.render()方法实现;

  • DispatcherServlet一级控制器根据请求标识(如URL)从HandlerMapping查找对应二级控制器Controller,并把请求转发给该Controller;
  • Controller处理完成后返回ModelAndView给DispatcherServlet一级控制器;
  • DispatcherServlet一级控制器根据ModelAndView对象,通过视图解析器ViewResolver获取视图实例View;
  • DispatcherServlet一级控制器调用view.render()方法做实际的视图渲染;

【DispatcherServlet】

protected void render(ModelAndView mv, HttpServletRequest request, HttpServletResponse response) throws Exception {Locale locale = this.localeResolver != null ? this.localeResolver.resolveLocale(request) : request.getLocale();response.setLocale(locale);String viewName = mv.getViewName();  View view;if (viewName != null) { // 逻辑视图名不为空 view = this.resolveViewName(viewName, mv.getModelInternal(), locale, request); // 解析该逻辑视图名得到视图实例 if (view == null) {String var10002 = mv.getViewName();throw new ServletException("Could not resolve view with name '" + var10002 + "' in servlet with name '" + this.getServletName() + "'");}} else {view = mv.getView(); // 否则直接从 ModelAndView 中获取视图实例 if (view == null) {throw new ServletException("ModelAndView [" + mv + "] neither contains a view name nor a View object in servlet with name '" + this.getServletName() + "'");}}if (this.logger.isTraceEnabled()) {this.logger.trace("Rendering view [" + view + "] ");}try {if (mv.getStatus() != null) {request.setAttribute(View.RESPONSE_STATUS_ATTRIBUTE, mv.getStatus());response.setStatus(mv.getStatus().value());}view.render(mv.getModelInternal(), request, response); // 视图渲染 } catch (Exception var8) {if (this.logger.isDebugEnabled()) {this.logger.debug("Error rendering view [" + view + "]", var8);}throw var8;}
}

【AbstractView#render()】 视图渲染方法

public void render(@Nullable Map<String, ?> model, HttpServletRequest request, HttpServletResponse response) throws Exception {if (this.logger.isDebugEnabled()) {Log var10000 = this.logger;String var10001 = this.formatViewName();var10000.debug("View " + var10001 + ", model " + (model != null ? model : Collections.emptyMap()) + (this.staticAttributes.isEmpty() ? "" : ", static attributes " + this.staticAttributes));}Map<String, Object> mergedModel = this.createMergedOutputModel(model, request, response); // 合并模型数据 this.prepareResponse(request, response);this.renderMergedOutputModel(mergedModel, this.getRequestToExpose(request), response); // 渲染合并内后的模型数据 
} 


【5.1】View实现原理

1)View视图的工作: 使用相应的技术API将模版和最终提供的模型数据合并在一起, 最终输出结果页面给客户端;

【JstlView】jstl标签视图,继承InternalResourceView(jsp视图)

public class JstlView extends InternalResourceView {@Nullableprivate MessageSource messageSource;public JstlView() {}public JstlView(String url) {super(url);}public JstlView(String url, MessageSource messageSource) {this(url);this.messageSource = messageSource;}protected void initServletContext(ServletContext servletContext) {if (this.messageSource != null) {this.messageSource = JstlUtils.getJstlAwareMessageSource(servletContext, this.messageSource);}super.initServletContext(servletContext);}protected void exposeHelpers(HttpServletRequest request) throws Exception {if (this.messageSource != null) {JstlUtils.exposeLocalizationContext(request, this.messageSource);} else {JstlUtils.exposeLocalizationContext(new RequestContext(request, this.getServletContext()));}}
}


【5.2】View实现类(基类AbstractView)

1)View基类:AbstractView; 所有视图类都继承AbstractView ;

【AbstractView】

public abstract class AbstractView extends WebApplicationObjectSupport implements View, BeanNameAware {public static final String DEFAULT_CONTENT_TYPE = "text/html;charset=ISO-8859-1";private static final int OUTPUT_BYTE_ARRAY_INITIAL_SIZE = 4096;@Nullableprivate String contentType = "text/html;charset=ISO-8859-1";@Nullableprivate String requestContextAttribute;private final Map<String, Object> staticAttributes = new LinkedHashMap(); // 静态属性    ... // 视图渲染 public void render(@Nullable Map<String, ?> model, HttpServletRequest request, HttpServletResponse response) throws Exception {if (this.logger.isDebugEnabled()) {Log var10000 = this.logger;String var10001 = this.formatViewName();var10000.debug("View " + var10001 + ", model " + (model != null ? model : Collections.emptyMap()) + (this.staticAttributes.isEmpty() ? "" : ", static attributes " + this.staticAttributes));}Map<String, Object> mergedModel = this.createMergedOutputModel(model, request, response); // 1 合并模型数据 this.prepareResponse(request, response); // 2 准备响应报文 this.renderMergedOutputModel(mergedModel, this.getRequestToExpose(request), response); // 3 渲染模型数据}// 合并模型数据 protected Map<String, Object> createMergedOutputModel(@Nullable Map<String, ?> model, HttpServletRequest request, HttpServletResponse response) {Map<String, Object> pathVars = this.exposePathVariables ? (Map)request.getAttribute(View.PATH_VARIABLES) : null;int size = this.staticAttributes.size();size += model != null ? model.size() : 0;size += pathVars != null ? pathVars.size() : 0;Map<String, Object> mergedModel = CollectionUtils.newLinkedHashMap(size); // 合并后的模型数据容器mapmergedModel.putAll(this.staticAttributes); // 合并静态属性 if (pathVars != null) {mergedModel.putAll(pathVars); // 合并路径变量}if (model != null) {mergedModel.putAll(model); // 合并ModelAndView模型数据 }if (this.requestContextAttribute != null) {// 合并请求上下文数据  mergedModel.put(this.requestContextAttribute, this.createRequestContext(request, response, mergedModel));}return mergedModel;}protected RequestContext createRequestContext(HttpServletRequest request, HttpServletResponse response, Map<String, Object> model) {return new RequestContext(request, response, this.getServletContext(), model);}// 准备响应报文 protected void prepareResponse(HttpServletRequest request, HttpServletResponse response) {if (this.generatesDownloadContent()) {response.setHeader("Pragma", "private");response.setHeader("Cache-Control", "private, must-revalidate");}}
}

2)AbstractView定义的视图渲染流程:

  • 合并模型数据:合并静态属性,合并路径变量,合并ModelAndView模型数据 , 合并请求上下文数据 ;
  • 准备响应报文:若是下载文件,则设置响应头;
  • 渲染模型数据:调用renderMergedOutputModel()方法渲染,但该方法是抽象方法,需要子类实现;


【5.3】AbstractView的子类AbstractUrlBasedView

1)AbstractUrlBasedView:继承自AbstractView,仅定义了一个url属性;

  • 所有需要指定url的视图都继承AbstractUrlBasedView;
  • 不需要指定url的视图继承 AbstractView(如二进制文件视图);

【AbstractUrlBasedView】

public abstract class AbstractUrlBasedView extends AbstractView implements InitializingBean {@Nullableprivate String url;protected AbstractUrlBasedView() {}protected AbstractUrlBasedView(String url) {this.url = url;}public void setUrl(@Nullable String url) {this.url = url;}@Nullablepublic String getUrl() {return this.url;}public void afterPropertiesSet() throws Exception {if (this.isUrlRequired() && this.getUrl() == null) {throw new IllegalArgumentException("Property 'url' is required");}}protected boolean isUrlRequired() {return true;}public boolean checkResource(Locale locale) throws Exception {return true;}public String toString() {String var10000 = super.toString();return var10000 + "; URL [" + this.getUrl() + "]";}
}


【5.3.1】使用jsp技术的view

1)使用jsp技术的view:

  • InternalResourceView ; (支持jsp技术的主要视图类)
  • JstlView;(支持jstl标签的视图类)


【5.3.2】使用通用模版技术的view

1)通用模版技术,包括 FreeMarker, Velocity, Groovy;

  • FreeMarkerView;
  • VelocityVIew;
  • GroovyMarkupView

2)FreeMarkerView 与 VelocityVIew 都继承自 AbstractTemplateView, 如下;

在这里插入图片描述



【5.3.3】面向二进制文档格式的View

1)二进制文档,包括pdf,excel, 图片等;

  • AbstractPdfView :pdf视图
  • AbstractPdfStamperView :pdf视图
  • AbstractXlsView :excel视图;
  • AbstractXlsxView :excel实体;
  • AbstractXlsxStreamingView :excel视图;
public abstract class AbstractPdfView extends AbstractView {public AbstractPdfView() {this.setContentType("application/pdf");}...
}public abstract class AbstractPdfStamperView extends AbstractUrlBasedView {public AbstractPdfStamperView() {this.setContentType("application/pdf");}... 
}public abstract class AbstractXlsView extends AbstractView {public AbstractXlsView() {this.setContentType("application/vnd.ms-excel");}...
}public abstract class AbstractXlsxView extends AbstractXlsView {public AbstractXlsxView() {this.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");}protected Workbook createWorkbook(Map<String, Object> model, HttpServletRequest request) {return new XSSFWorkbook();}
}public abstract class AbstractXlsxStreamingView extends AbstractXlsxView {public AbstractXlsxStreamingView() {}protected SXSSFWorkbook createWorkbook(Map<String, Object> model, HttpServletRequest request) {return new SXSSFWorkbook();}protected void renderWorkbook(Workbook workbook, HttpServletResponse response) throws IOException {super.renderWorkbook(workbook, response);((SXSSFWorkbook)workbook).dispose();}
}


【5.3.4】重定向视图RedirectView

1)springmvc实现重定向的两种方式

  • 方式1:新建 RedirectView,并封装到ModelAndView返回;
    • 若RedirectView的 http10Compatible属性为true: RedirectView将直接通过HttpServletResponse的sendRedirect() 方法进行重定向;
    • 否则: 通过设置http状态为303以及http header(“Location”) 达到相同目的;
  • 方式2:逻辑视图名称前使用 redirect 或 forward前缀;

【UserController】重定向

public class UserController extends AbstractController {private UserAppService userAppService;@Overrideprotected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response) throws Exception {ModelAndView modelAndView = new ModelAndView();modelAndView.addObject("userList", userAppService.listUser());// 方式1: 通过RedirectView实现重定向
//        modelAndView.setView(new RedirectView("bankCardList.do"));// 方式2: 逻辑视图名称前新增redirect 前缀实现重定向modelAndView = new ModelAndView("redirect:bankCardList.do");return modelAndView;}public void setUserAppService(UserAppService userAppService) {this.userAppService = userAppService;}
}

重定向效果:

在这里插入图片描述



【5.3.5】使用XSLT技术的View

1)XSLT技术: 在计算机科学中,可扩展样式表转换语言(英语:Extensible Stylesheet Language Transformations,缩写XSLT)是一种样式转换标记语言,可以将XML数据转换为另外的XML或其它格式。

  • XsltView


【5.4】自定义View实现

1)业务场景:通过springmvc的pdf视图展示pdf文件

2)自定义view,需要继承 AbstractUrlBasedView,或者 AbstractView;

【PdfUrlViewController】

public class PdfUrlViewController extends AbstractController {@Overrideprotected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response) throws Exception {ModelAndView modelAndView = new ModelAndView();modelAndView.setView(TomPdfView.build(getClass().getResource("/").getPath() + "/socialNetworkPropagation.pdf"));return modelAndView;}
}

【TomPdfView】自定义View类,继承 AbstractUrlBasedView

public class TomPdfView extends AbstractUrlBasedView {public TomPdfView(String url) {super(url);setContentType("application/pdf");}public static TomPdfView build(String url) {return new TomPdfView(url);}@Overrideprotected void renderMergedOutputModel(Map<String, Object> model, HttpServletRequest request, HttpServletResponse response) throws Exception {response.setContentType(getContentType());InputStream inputStream =new FileInputStream(getUrl());OutputStream outputStream = response.getOutputStream();BusiIOUtils.copy(inputStream, outputStream);outputStream.flush();inputStream.close();outputStream.close();}
}

【dispatcher-servlet.xml】

<bean id="pdfUrlViewController" class="com.tom.springmvc.controller.file.PdfUrlViewController" />

【访问效果】

在这里插入图片描述

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