Springmvc保姆级丝滑教程(一文搞懂系列)（1）https://developer.aliyun.com/article/1411504
10、文件上传和下载
10.1、文件下载
ResponseEntity用于控制器方法的返回值类型，该控制器方法的返回值就是响应到浏览器的响应报文
使用ResponseEntity实现下载文件的功能
@RequestMapping("/testDown") public ResponseEntity<byte[]> testResponseEntity(HttpSession session) throws IOException { //获取ServletContext对象 ServletContext servletContext = session.getServletContext(); //获取服务器中文件的真实路径 String realPath = servletContext.getRealPath("/static/img/1.jpg"); //创建输入流 InputStream is = new FileInputStream(realPath); //创建字节数组 byte[] bytes = new byte[is.available()]; //将流读到字节数组中 is.read(bytes); //创建HttpHeaders对象设置响应头信息 MultiValueMap<String, String> headers = new HttpHeaders(); //设置要下载方式以及下载文件的名字 headers.add("Content-Disposition", "attachment;filename=1.jpg"); //设置响应状态码 HttpStatus statusCode = HttpStatus.OK; //创建ResponseEntity对象 ResponseEntity<byte[]> responseEntity = new ResponseEntity<>(bytes, headers,statusCode); //关闭输入流 is.close(); return responseEntity; }
10.2、文件上传
文件上传要求form表单的请求方式必须为post，并且添加属性enctype=“multipart/form-data”
SpringMVC中将上传的文件封装到MultipartFile对象中，通过此对象可以获取文件相关信息
上传步骤：
①添加依赖：
<!-- https://mvnrepository.com/artifact/commons-fileupload/commons-fileupload --> <dependency> <groupId>commons-fileupload</groupId> <artifactId>commons-fileupload</artifactId> <version>1.3.1</version> </dependency>
②在SpringMVC的配置文件中添加配置：
<!--必须通过文件解析器的解析才能将文件转换为MultipartFile对象--> <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"> </bean>
③控制器方法：
@RequestMapping("/testUp") public String testUp(MultipartFile photo, HttpSession session) throws IOException { //获取上传的文件的文件名 String fileName = photo.getOriginalFilename(); //处理文件重名问题 String hzName = fileName.substring(fileName.lastIndexOf(".")); fileName = UUID.randomUUID().toString() + hzName; //获取服务器中photo目录的路径 ServletContext servletContext = session.getServletContext(); String photoPath = servletContext.getRealPath("photo"); File file = new File(photoPath); if(!file.exists()){ file.mkdir(); } String finalPath = photoPath + File.separator + fileName; //实现上传功能 photo.transferTo(new File(finalPath)); return "success"; }
11、拦截器
11.1、拦截器的配置
SpringMVC中的拦截器用于拦截控制器方法的执行
SpringMVC中的拦截器需要实现HandlerInterceptor
SpringMVC的拦截器必须在SpringMVC的配置文件中进行配置：
<bean class="com.atguigu.interceptor.FirstInterceptor"></bean> <ref bean="firstInterceptor"></ref> <!-- 以上两种配置方式都是对DispatcherServlet所处理的所有的请求进行拦截 --> <mvc:interceptor> <mvc:mapping path="/**"/> <mvc:exclude-mapping path="/testRequestEntity"/> <ref bean="firstInterceptor"></ref> </mvc:interceptor> <!-- 以上配置方式可以通过ref或bean标签设置拦截器，通过mvc:mapping设置需要拦截的请求， 通过mvc:exclude-mapping设置需要排除的请求，即不需要拦截的请求 -->
11.2、拦截器的三个抽象方法
SpringMVC中的拦截器有三个抽象方法：
preHandle：控制器方法执行之前执行preHandle()，其boolean类型的返回值表示是否拦截或放行，返回true为放行，即调用控制器方法；返回false表示拦截，即不调用控制器方法
postHandle：控制器方法执行之后执行postHandle()
afterCompletion：处理完视图和模型数据，渲染视图完毕之后执行afterCompletion()
11.3、多个拦截器的执行顺序
①若每个拦截器的preHandle()都返回true
此时多个拦截器的执行顺序和拦截器在SpringMVC的配置文件的配置顺序有关：
preHandle()会按照配置的顺序执行，而postHandle()和afterCompletion()会按照配置的反序执行
②若某个拦截器的preHandle()返回了false
preHandle()返回false和它之前的拦截器的preHandle()都会执行，postHandle()都不执行，返回false
的拦截器之前的拦截器的afterCompletion()会执行
12、异常处理器
12.1、基于配置的异常处理
SpringMVC提供了一个处理控制器方法执行过程中所出现的异常的接口：HandlerExceptionResolver
HandlerExceptionResolver接口的实现类有：DefaultHandlerExceptionResolver和
SimpleMappingExceptionResolver
SpringMVC提供了自定义的异常处理器SimpleMappingExceptionResolver，使用方式：
<bean class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver"> <property name="exceptionMappings"> <props> <!-- properties的键表示处理器方法执行过程中出现的异常 properties的值表示若出现指定异常时，设置一个新的视图名称，跳转到指定页面 --> <prop key="java.lang.ArithmeticException">error</prop> </props> </property> <!-- exceptionAttribute属性设置一个属性名，将出现的异常信息在请求域中进行共享 --> <property name="exceptionAttribute" value="ex"></property> </bean>
12.2、基于注解的异常处理
//@ControllerAdvice将当前类标识为异常处理的组件 @ControllerAdvice public class ExceptionController { //@ExceptionHandler用于设置所标识方法处理的异常 @ExceptionHandler(ArithmeticException.class) //ex表示当前请求处理中出现的异常对象 public String handleArithmeticException(Exception ex, Model model){ model.addAttribute("ex", ex); return "error"; } }
13、注解配置SpringMVC
使用配置类和注解代替web.xml和SpringMVC配置文件的功能
13.1、创建初始化类，代替web.xml
在Servlet3.0环境中，容器会在类路径中查找实现javax.servlet.ServletContainerInitializer接口的类，
如果找到的话就用它来配置Servlet容器。 Spring提供了这个接口的实现，名为
SpringServletContainerInitializer，这个类反过来又会查找实现WebApplicationInitializer的类并将配
置的任务交给它们来完成。Spring3.2引入了一个便利的WebApplicationInitializer基础实现，名为
AbstractAnnotationConfigDispatcherServletInitializer，当我们的类扩展了
AbstractAnnotationConfigDispatcherServletInitializer并将其部署到Servlet3.0容器的时候，容器会自动发现它，并用它来配置Servlet上下文。
public class WebInit extends AbstractAnnotationConfigDispatcherServletInitializer { /** * 指定spring的配置类 * @return */ @Override protected Class<?>[] getRootConfigClasses() { return new Class[]{SpringConfig.class}; } /** * 指定SpringMVC的配置类 * @return */ @Override protected Class<?>[] getServletConfigClasses() { return new Class[]{WebConfig.class}; } /** * 指定DispatcherServlet的映射规则，即url-pattern * @return */ @Override protected String[] getServletMappings() { return new String[]{"/"}; } /** * 添加过滤器 * @return */ @Override protected Filter[] getServletFilters() { CharacterEncodingFilter encodingFilter = new CharacterEncodingFilter(); encodingFilter.setEncoding("UTF-8"); encodingFilter.setForceRequestEncoding(true); HiddenHttpMethodFilter hiddenHttpMethodFilter = newHiddenHttpMethodFilter(); return new Filter[]{encodingFilter, hiddenHttpMethodFilter}; } }
13.2、创建SpringConfig配置类，代替spring的配置文件
@Configuration public class SpringConfig { //ssm整合之后，spring的配置信息写在此类中 }
13.3、创建WebConfig配置类，代替SpringMVC的配置文件
@Configuration //扫描组件 @ComponentScan("com.atguigu.mvc.controller") //开启MVC注解驱动 @EnableWebMvc public class WebConfig implements WebMvcConfigurer { //使用默认的servlet处理静态资源 @Override public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) { configurer.enable(); } //配置文件上传解析器 @Bean public CommonsMultipartResolver multipartResolver(){ return new CommonsMultipartResolver(); } //配置拦截器 @Override public void addInterceptors(InterceptorRegistry registry) { FirstInterceptor firstInterceptor = new FirstInterceptor(); registry.addInterceptor(firstInterceptor).addPathPatterns("/**"); } //配置视图控制 /*@Override public void addViewControllers(ViewControllerRegistry registry) { registry.addViewController("/").setViewName("index"); }*/ //配置异常映射 /*@Override public void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> resolvers) { SimpleMappingExceptionResolver exceptionResolver = new SimpleMappingExceptionResolver(); Properties prop = new Properties(); prop.setProperty("java.lang.ArithmeticException", "error"); //设置异常映射 exceptionResolver.setExceptionMappings(prop); //设置共享异常信息的键 exceptionResolver.setExceptionAttribute("ex"); resolvers.add(exceptionResolver); }*/ //配置生成模板解析器 @Bean public ITemplateResolver templateResolver() { WebApplicationContext webApplicationContext =ContextLoader.getCurrentWebApplicationContext(); // ServletContextTemplateResolver需要一个ServletContext作为构造参数，可通过WebApplicationContext 的方法获得 ServletContextTemplateResolver templateResolver = new ServletContextTemplateResolver(webApplicationContext.getServletContext()); templateResolver.setPrefix("/WEB-INF/templates/"); templateResolver.setSuffix(".html"); templateResolver.setCharacterEncoding("UTF-8"); templateResolver.setTemplateMode(TemplateMode.HTML); return templateResolver; } //生成模板引擎并为模板引擎注入模板解析器 @Bean public SpringTemplateEngine templateEngine(ITemplateResolver templateResolver) { SpringTemplateEngine templateEngine = new SpringTemplateEngine(); templateEngine.setTemplateResolver(templateResolver); return templateEngine; } //生成视图解析器并未解析器注入模板引擎 @Bean public ViewResolver viewResolver(SpringTemplateEngine templateEngine) { ThymeleafViewResolver viewResolver = new ThymeleafViewResolver(); viewResolver.setCharacterEncoding("UTF-8"); viewResolver.setTemplateEngine(templateEngine); return viewResolver; } }
13.4、测试功能
@RequestMapping("/") public String index(){ return "index"; }
14、SpringMVC执行流程
14.1、SpringMVC常用组件
- DispatcherServlet：前端控制器，不需要工程师开发，由框架提供
作用：统一处理请求和响应，整个流程控制的中心，由它调用其它组件处理用户的请求
- HandlerMapping：处理器映射器，不需要工程师开发，由框架提供
作用：根据请求的url、method等信息查找Handler，即控制器方法
- Handler：处理器，需要工程师开发
作用：在DispatcherServlet的控制下Handler对具体的用户请求进行处理
- HandlerAdapter：处理器适配器，不需要工程师开发，由框架提供
作用：通过HandlerAdapter对处理器（控制器方法）进行执行
- ViewResolver：视图解析器，不需要工程师开发，由框架提供
作用：进行视图解析，得到相应的视图，例如：ThymeleafView、InternalResourceView、
RedirectView
- View：视图
作用：将模型数据通过页面展示给用户
14.2、DispatcherServlet初始化过程
DispatcherServlet 本质上是一个 Servlet，所以天然的遵循 Servlet 的生命周期。所以宏观上是 Servlet生命周期来进行调度。
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①初始化WebApplicationContext
所在类：org.springframework.web.servlet.FrameworkServlet
protected WebApplicationContext initWebApplicationContext() { WebApplicationContext rootContext = WebApplicationContextUtils.getWebApplicationContext(getServletContext()); WebApplicationContext wac = null; if (this.webApplicationContext != null) { // A context instance was injected at construction time -> use it wac = this.webApplicationContext; if (wac instanceof ConfigurableWebApplicationContext) { ConfigurableWebApplicationContext cwac =(ConfigurableWebApplicationContext) wac; if (!cwac.isActive()) { // The context has not yet been refreshed -> provide services such as // setting the parent context, setting the application context id, etc if (cwac.getParent() == null) { // The context instance was injected without an explicit parent -> set // the root application context (if any; may be null) as the parent cwac.setParent(rootContext); } configureAndRefreshWebApplicationContext(cwac); } } } if (wac == null) { // No context instance was injected at construction time -> see if one // has been registered in the servlet context. If one exists, it is assumed // that the parent context (if any) has already been set and that the // user has performed any initialization such as setting the context id wac = findWebApplicationContext(); } if (wac == null) { // No context instance is defined for this servlet -> create a local one // 创建WebApplicationContext wac = createWebApplicationContext(rootContext); } if (!this.refreshEventReceived) { // Either the context is not a ConfigurableApplicationContext with refresh // support or the context injected at construction time had already been // refreshed -> trigger initial onRefresh manually here. synchronized (this.onRefreshMonitor) { // 刷新WebApplicationContext onRefresh(wac); } } if (this.publishContext) { // Publish the context as a servlet context attribute. // 将IOC容器在应用域共享 String attrName = getServletContextAttributeName(); getServletContext().setAttribute(attrName, wac); } return wac; }
②创建WebApplicationContext
所在类：org.springframework.web.servlet.FrameworkServlet
protected WebApplicationContext createWebApplicationContext(@Nullable ApplicationContext parent) { Class<?> contextClass = getContextClass(); if (!ConfigurableWebApplicationContext.class.isAssignableFrom(contextClass)) { throw new ApplicationContextException("Fatal initialization error in servlet with name '" +getServletName() + "': custom WebApplicationContext class [" + contextClass.getName() + "] is not of type ConfigurableWebApplicationContext"); } // 通过反射创建 IOC 容器对象 ConfigurableWebApplicationContext wac = (ConfigurableWebApplicationContext)BeanUtils.instantiateClass(contextClass); wac.setEnvironment(getEnvironment()); // 设置父容器 wac.setParent(parent); String configLocation = getContextConfigLocation(); if (configLocation != null) { wac.setConfigLocation(configLocation); } configureAndRefreshWebApplicationContext(wac); return wac; }
③DispatcherServlet初始化策略
FrameworkServlet创建WebApplicationContext后，刷新容器，调用onRefresh(wac)，此方法在
DispatcherServlet中进行了重写，调用了initStrategies(context)方法，初始化策略，即初始化
DispatcherServlet的各个组件
所在类：org.springframework.web.servlet.DispatcherServlet
protected void initStrategies(ApplicationContext context) { initMultipartResolver(context); initLocaleResolver(context); initThemeResolver(context); initHandlerMappings(context); initHandlerAdapters(context); initHandlerExceptionResolvers(context); initRequestToViewNameTranslator(context); initViewResolvers(context); initFlashMapManager(context); }
14.3、DispatcherServlet调用组件处理请求
①processRequest()
FrameworkServlet重写HttpServlet中的service()和doXxx()，这些方法中调用了
processRequest(request, response)
所在类：org.springframework.web.servlet.FrameworkServlet
protected final void processRequest(HttpServletRequest request,HttpServletResponse response)throws ServletException, IOException { long startTime = System.currentTimeMillis(); Throwable failureCause = null; LocaleContext previousLocaleContext = LocaleContextHolder.getLocaleContext(); LocaleContext localeContext = buildLocaleContext(request); RequestAttributes previousAttributes = RequestContextHolder.getRequestAttributes(); ServletRequestAttributes requestAttributes = buildRequestAttributes(request,response, previousAttributes); WebAsyncManager asyncManager = WebAsyncUtils.getAsyncManager(request); asyncManager.registerCallableInterceptor(FrameworkServlet.class.getName(),new RequestBindingInterceptor()); initContextHolders(request, localeContext, requestAttributes); try { // 执行服务，doService()是一个抽象方法，在DispatcherServlet中进行了重写 doService(request, response); } catch (ServletException | IOException ex) { failureCause = ex; throw ex; } catch (Throwable ex) { failureCause = ex; throw new NestedServletException("Request processing failed", ex); } finally { resetContextHolders(request, previousLocaleContext, previousAttributes); if (requestAttributes != null) { requestAttributes.requestCompleted(); } logResult(request, response, failureCause, asyncManager); publishRequestHandledEvent(request, response, startTime, failureCause); } }
②doService()
所在类：org.springframework.web.servlet.DispatcherServlet
@Override protected void doService(HttpServletRequest request, HttpServletResponse response) throws Exception { logRequest(request); // Keep a snapshot of the request attributes in case of an include, // to be able to restore the original attributes after the include. Map<String, Object> attributesSnapshot = null; if (WebUtils.isIncludeRequest(request)) { attributesSnapshot = new HashMap<>(); Enumeration<?> attrNames = request.getAttributeNames(); while (attrNames.hasMoreElements()) { String attrName = (String) attrNames.nextElement(); if (this.cleanupAfterInclude || attrName.startsWith(DEFAULT_STRATEGIES_PREFIX)) { attributesSnapshot.put(attrName,request.getAttribute(attrName)); } } } // Make framework objects available to handlers and view objects. request.setAttribute(WEB_APPLICATION_CONTEXT_ATTRIBUTE,getWebApplicationContext()); request.setAttribute(LOCALE_RESOLVER_ATTRIBUTE, this.localeResolver); request.setAttribute(THEME_RESOLVER_ATTRIBUTE, this.themeResolver); request.setAttribute(THEME_SOURCE_ATTRIBUTE, getThemeSource()); if (this.flashMapManager != null) { FlashMap inputFlashMap = this.flashMapManager.retrieveAndUpdate(request,response); if (inputFlashMap != null) { request.setAttribute(INPUT_FLASH_MAP_ATTRIBUTE,Collections.unmodifiableMap(inputFlashMap)); } request.setAttribute(OUTPUT_FLASH_MAP_ATTRIBUTE, new FlashMap()); request.setAttribute(FLASH_MAP_MANAGER_ATTRIBUTE, this.flashMapManager); } RequestPath requestPath = null; if (this.parseRequestPath && !ServletRequestPathUtils.hasParsedRequestPath(request)) { requestPath = ServletRequestPathUtils.parseAndCache(request); } try { // 处理请求和响应 doDispatch(request, response); } finally { if (!WebAsyncUtils.getAsyncManager(request).isConcurrentHandlingStarted()) { // Restore the original attribute snapshot, in case of an include. if (attributesSnapshot != null) { restoreAttributesAfterInclude(request, attributesSnapshot); } } if (requestPath != null) { ServletRequestPathUtils.clearParsedRequestPath(request); } } }
③doDispatch()
所在类：org.springframework.web.servlet.DispatcherServlet
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); // Determine handler for the current request. /* mappedHandler：调用链 包含handler、interceptorList、interceptorIndex handler：浏览器发送的请求所匹配的控制器方法 interceptorList：处理控制器方法的所有拦截器集合 interceptorIndex：拦截器索引，控制拦截器afterCompletion()的执行 */ mappedHandler = getHandler(processedRequest); if (mappedHandler == null) { noHandlerFound(processedRequest, response); return; } // Determine handler adapter for the current request. // 通过控制器方法创建相应的处理器适配器，调用所对应的控制器方法 HandlerAdapter ha = getHandlerAdapter(mappedHandler.getHandler()); // Process last-modified header, if supported by the handler. String method = request.getMethod(); boolean isGet = "GET".equals(method); if (isGet || "HEAD".equals(method)) { long lastModified = ha.getLastModified(request,mappedHandler.getHandler()); if (new ServletWebRequest(request,response).checkNotModified(lastModified) && isGet) { return; } } // 调用拦截器的preHandle() if (!mappedHandler.applyPreHandle(processedRequest, response)) { return; } // Actually invoke the handler. // 由处理器适配器调用具体的控制器方法，最终获得ModelAndView对象 mv = ha.handle(processedRequest, response,mappedHandler.getHandler()); if (asyncManager.isConcurrentHandlingStarted()) { return; } applyDefaultViewName(processedRequest, mv); // 调用拦截器的postHandle() mappedHandler.applyPostHandle(processedRequest, response, mv); } catch (Exception ex) { dispatchException = ex; } catch (Throwable err) { // As of 4.3, we're processing Errors thrown from handler methods as well, // making them available for @ExceptionHandler methods and otherscenarios. dispatchException = new NestedServletException("Handler dispatchfailed", err); } // 后续处理：处理模型数据和渲染视图 processDispatchResult(processedRequest, response, mappedHandler, mv,dispatchException); } catch (Exception ex) { triggerAfterCompletion(processedRequest, response, mappedHandler, ex); } catch (Throwable err) { triggerAfterCompletion(processedRequest, response, mappedHandler,new NestedServletException("Handler processingfailed", err)); } finally { if (asyncManager.isConcurrentHandlingStarted()) { // Instead of postHandle and afterCompletion if (mappedHandler != null) { mappedHandler.applyAfterConcurrentHandlingStarted(processedRequest, response); } } else { // Clean up any resources used by a multipart request. if (multipartRequestParsed) { cleanupMultipart(processedRequest); } } } }
④processDispatchResult()
private void processDispatchResult(HttpServletRequest request,HttpServletResponse response,@Nullable HandlerExecutionChain mappedHandler, @Nullable ModelAndView mv,@Nullable Exception exception) throws Exception { boolean errorView = false; if (exception != null) { if (exception instanceof ModelAndViewDefiningException) { logger.debug("ModelAndViewDefiningException encountered",exception); mv = ((ModelAndViewDefiningException) exception).getModelAndView(); } else { Object handler = (mappedHandler != null ? mappedHandler.getHandler(): null); mv = processHandlerException(request, response, handler, exception); errorView = (mv != null); } } // Did the handler return a view to render? if (mv != null && !mv.wasCleared()) { // 处理模型数据和渲染视图 render(mv, request, response); if (errorView) { WebUtils.clearErrorRequestAttributes(request); } } else { if (logger.isTraceEnabled()) { logger.trace("No view rendering, null ModelAndView returned."); } } if (WebAsyncUtils.getAsyncManager(request).isConcurrentHandlingStarted()) { // Concurrent handling started during a forward return; } if (mappedHandler != null) { // Exception (if any) is already handled.. // 调用拦截器的afterCompletion() mappedHandler.triggerAfterCompletion(request, response, null); } }
14.4、SpringMVC的执行流程
1)用户向服务器发送请求，请求被SpringMVC 前端控制器 DispatcherServlet捕获。
2)DispatcherServlet对请求URL进行解析，得到请求资源标识符（URI），判断请求URI对应的映射：
a) 不存在
i. 再判断是否配置了mvc:default-servlet-handler
ii. 如果没配置，则控制台报映射查找不到，客户端展示404错误
iii. 如果有配置，则访问目标资源（一般为静态资源，如：JS,CSS,HTML），找不到客户端也会展示404错误
b) 存在则执行下面的流程
3)根据该URI，调用HandlerMapping获得该Handler配置的所有相关的对象（包括Handler对象以及Handler对象对应的拦截器），最后HandlerExecutionChain执行链对象的形式返回。
4)DispatcherServlet 根据获得的Handler，选择一个合适的HandlerAdapter。
5)如果成功获得HandlerAdapter，此时将开始执行拦截器的preHandler(…)方法【正向】
6)提取Request中的模型数据，填充Handler入参，开始执行Handler（Controller)方法，处理请求。在填充Handler的入参过程中，根据你的配置，Spring将帮你做一些额外的工作：
a) HttpMessageConveter： 将请求消息（如Json、xml等数据）转换成一个对象，将对象转换为指定的响应信息
b) 数据转换：对请求消息进行数据转换。如String转换成Integer、Double等
c) 数据格式化：对请求消息进行数据格式化。 如将字符串转换成格式化数字或格式化日期等
d) 数据验证： 验证数据的有效性（长度、格式等），验证结果存储到BindingResult或Error中
7)Handler执行完成后，向DispatcherServlet 返回一个ModelAndView对象。
8)此时将开始执行拦截器的postHandle(…)方法【逆向】。
9)根据返回的ModelAndView（此时会判断是否存在异常：如果存在异常，则执行HandlerExceptionResolver进行异常处理）选择一个适合的ViewResolver进行视图解析，根据Model和View，来渲染视图。
10)渲染视图完毕执行拦截器的afterCompletion(…)方法【逆向】。
11)将渲染结果返回给客户端。
四、SSM整合
4.1、ContextLoaderListener
Spring提供了监听器ContextLoaderListener，实现ServletContextListener接口，可监听
ServletContext的状态，在web服务器的启动，读取Spring的配置文件，创建Spring的IOC容器。web
应用中必须在web.xml中配置
<listener> <!-- 配置Spring的监听器，在服务器启动时加载Spring的配置文件 Spring配置文件默认位置和名称：/WEB-INF/applicationContext.xml 可通过上下文参数自定义Spring配置文件的位置和名称 --> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <!--自定义Spring配置文件的位置和名称--> <context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:spring.xml</param-value> </context-param>
4.2、准备工作
①创建Maven Module
②导入依赖
<packaging>war</packaging> <properties> <spring.version>5.3.1</spring.version> </properties> <dependencies> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-beans</artifactId> <version>${spring.version}</version> </dependency> <!--springmvc--> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-jdbc</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aspects</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>${spring.version}</version> </dependency> <!-- Mybatis核心 --> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.5.7</version> </dependency> <!--mybatis和spring的整合包--> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis-spring</artifactId> <version>2.0.6</version> </dependency> <!-- 连接池 --> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>1.0.9</version> </dependency> <!-- junit测试 --> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> <scope>test</scope> </dependency> <!-- MySQL驱动 --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.16</version> </dependency> <!-- log4j日志 --> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.17</version> </dependency> <!-- https://mvnrepository.com/artifact/com.github.pagehelper/pagehelper --> <dependency> <groupId>com.github.pagehelper</groupId> <artifactId>pagehelper</artifactId> <version>5.2.0</version> </dependency> <!-- 日志 --> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-classic</artifactId> <version>1.2.3</version> </dependency> <!-- ServletAPI --> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>3.1.0</version> <scope>provided</scope> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.12.1</version> </dependency> <dependency> <groupId>commons-fileupload</groupId> <artifactId>commons-fileupload</artifactId> <version>1.3.1</version> </dependency> <!-- Spring5和Thymeleaf整合包 --> <dependency> <groupId>org.thymeleaf</groupId> <artifactId>thymeleaf-spring5</artifactId> <version>3.0.12.RELEASE</version> </dependency> </dependencies>
③创建表
CREATE TABLE `t_emp` ( `emp_id` int(11) NOT NULL AUTO_INCREMENT, `emp_name` varchar(20) DEFAULT NULL, `age` int(11) DEFAULT NULL, `sex` char(1) DEFAULT NULL, `email` varchar(50) DEFAULT NULL, PRIMARY KEY (`emp_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8
4.3、配置web.xml
<!-- 配置Spring的编码过滤器 --> <filter> <filter-name>CharacterEncodingFilter</filter-name> <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class> <init-param> <param-name>encoding</param-name> <param-value>UTF-8</param-value> </init-param> <init-param> <param-name>forceEncoding</param-name> <param-value>true</param-value> </init-param> </filter> <filter-mapping> <filter-name>CharacterEncodingFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <!-- 配置处理请求方式PUT和DELETE的过滤器 --> <filter> <filter-name>HiddenHttpMethodFilter</filter-name> <filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filterclass> </filter> <filter-mapping> <filter-name>HiddenHttpMethodFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <!-- 配置SpringMVC的前端控制器 --> <servlet> <servlet-name>DispatcherServlet</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servletclass> <!-- 设置SpringMVC的配置文件的位置和名称 --> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:SpringMVC.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>DispatcherServlet</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> <!-- 设置Spring的配置文件的位置和名称 --> <context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:Spring.xml</param-value> </context-param> <!-- 配置Spring的监听器 --> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener>
4.4、创建SpringMVC的配置文件并配置
<!--扫描组件--> <context:component-scan base-package="com.atguigu.ssm.controller"> </context:component-scan> <!--配置视图解析器--> <bean id="viewResolver" class="org.thymeleaf.spring5.view.ThymeleafViewResolver"> <property name="order" value="1"/> <property name="characterEncoding" value="UTF-8"/> <property name="templateEngine"> <bean class="org.thymeleaf.spring5.SpringTemplateEngine"> <property name="templateResolver"> <bean class="org.thymeleaf.spring5.templateresolver.SpringResourceTemplateResolver"> <!-- 视图前缀 --> <property name="prefix" value="/WEB-INF/templates/"/> <!-- 视图后缀 --> <property name="suffix" value=".html"/> <property name="templateMode" value="HTML5"/> <property name="characterEncoding" value="UTF-8" /> </bean> </property> </bean> </property> </bean> <!-- 配置访问首页的视图控制 --> <mvc:view-controller path="/" view-name="index"></mvc:view-controller> <!-- 配置默认的servlet处理静态资源 --> <mvc:default-servlet-handler /> <!-- 开启MVC的注解驱动 --> <mvc:annotation-driven />
4.5、搭建MyBatis环境
①创建属性文件jdbc.properties
jdbc.user=root jdbc.password=atguigu jdbc.url=jdbc:mysql://localhost:3306/ssm?serverTimezone=UTC jdbc.driver=com.mysql.cj.jdbc.Driver
②创建MyBatis的核心配置文件mybatis-config.xml
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <settings> <!--将下划线映射为驼峰--> <setting name="mapUnderscoreToCamelCase" value="true"/> </settings> <plugins> <!--配置分页插件--> <plugin interceptor="com.github.pagehelper.PageInterceptor"></plugin> </plugins> </configuration>
③创建Mapper接口和映射文件
public interface EmployeeMapper { List<Employee> getEmployeeList(); }
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.atguigu.ssm.mapper.EmployeeMapper"> <select id="getEmployeeList" resultType="Employee"> select * from t_emp </select> </mapper>
④创建日志文件log4j.xml
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE log4j:configuration SYSTEM "log4j.dtd"> <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/"> <appender name="STDOUT" class="org.apache.log4j.ConsoleAppender"> <param name="Encoding" value="UTF-8" /> <layout class="org.apache.log4j.PatternLayout"> <param name="ConversionPattern" value="%-5p %d{MM-dd HH:mm:ss,SSS} %m (%F:%L) \n" /> </layout> </appender> <logger name="java.sql"> <level value="debug" /> </logger> <logger name="org.apache.ibatis"> <level value="info" /> </logger> <root> <level value="debug" /> <appender-ref ref="STDOUT" /> </root> </log4j:configuration>
4.6、创建Spring的配置文件并配置
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd"> <!--扫描组件--> <context:component-scan base-package="com.atguigu.ssm"> <context:exclude-filter type="annotation"expression="org.springframework.stereotype.Controller"/> </context:component-scan> <!-- 引入jdbc.properties --> <context:property-placeholder location="classpath:jdbc.properties"> </context:property-placeholder> <!-- 配置Druid数据源 --> <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"> <property name="driverClassName" value="${jdbc.driver}"></property> <property name="url" value="${jdbc.url}"></property> <property name="username" value="${jdbc.username}"></property> <property name="password" value="${jdbc.password}"></property> </bean> <!-- 配置用于创建SqlSessionFactory的工厂bean --> <bean class="org.mybatis.spring.SqlSessionFactoryBean"> <!-- 设置MyBatis配置文件的路径（可以不设置） --> <property name="configLocation" value="classpath:mybatis-config.xml"> </property> <!-- 设置数据源 --> <property name="dataSource" ref="dataSource"></property> <!-- 设置类型别名所对应的包 --> <property name="typeAliasesPackage" value="com.atguigu.ssm.pojo"> </property> <!-- 设置映射文件的路径 若映射文件所在路径和mapper接口所在路径一致，则不需要设置 --> <!-- <property name="mapperLocations" value="classpath:mapper/*.xml"> </property> --> </bean> <!-- 配置mapper接口的扫描配置 由mybatis-spring提供，可以将指定包下所有的mapper接口创建动态代理 并将这些动态代理作为IOC容器的bean管理 --> <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <property name="basePackage" value="com.atguigu.ssm.mapper"></property> </bean> </beans>
4.7、测试功能
①创建组件
实体类Employee
public class Employee { private Integer empId; private String empName; private Integer age; private String sex; private String email; public Employee() { } public Employee(Integer empId, String empName, Integer age, String sex, String email) { this.empId = empId; this.empName = empName; this.age = age; this.sex = sex; this.email = email; } public Integer getEmpId() { return empId; } public void setEmpId(Integer empId) { this.empId = empId; } public String getEmpName() { return empName; } public void setEmpName(String empName) { this.empName = empName; } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } public String getSex() { return sex; } public void setSex(String sex) { this.sex = sex; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } }
创建控制层组件EmployeeController
@Controller public class EmployeeController { @Autowired private EmployeeService employeeService; @RequestMapping(value = "/employee/page/{pageNum}", method = RequestMethod.GET) public String getEmployeeList(Model model, @PathVariable("pageNum") Integer pageNum){ PageInfo<Employee> page = employeeService.getEmployeeList(pageNum); model.addAttribute("page", page); return "employee_list"; } }
创建接口EmployeeService
public interface EmployeeService { PageInfo<Employee> getEmployeeList(Integer pageNum); }
创建实现类EmployeeServiceImpl
@Service public class EmployeeServiceImpl implements EmployeeService { @Autowired private EmployeeMapper employeeMapper; @Override public PageInfo<Employee> getEmployeeList(Integer pageNum) { PageHelper.startPage(pageNum, 4); List<Employee> list = employeeMapper.getEmployeeList(); PageInfo<Employee> page = new PageInfo<>(list, 5); return page; } }
②创建页面
<!DOCTYPE html> <html lang="en" xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"> <title>Employee Info</title> <link rel="stylesheet" th:href="@{/static/css/index_work.css}"> </head> <body> <table> <tr> <th colspan="6">Employee Info</th> </tr> <tr> <th>emp_id</th> <th>emp_name</th> <th>age</th> <th>sex</th> <th>email</th> <th>options</th> </tr> <tr th:each="employee : ${page.list}"> <td th:text="${employee.empId}"></td> <td th:text="${employee.empName}"></td> <td th:text="${employee.age}"></td> <td th:text="${employee.sex}"></td> <td th:text="${employee.email}"></td> <td> <a href="">delete</a> <a href="">update</a> </td> </tr> <tr> <td colspan="6"> <span th:if="${page.hasPreviousPage}"> <a th:href="@{/employee/page/1}">首页</a> <a th:href="@{'/employee/page/'+${page.prePage}}">上一页</a> </span> <span th:each="num : ${page.navigatepageNums}"> <a th:if="${page.pageNum==num}" th:href="@{'/employee/page/'+${num}}" th:text="'['+${num}+']'" style="color:red;"></a> <a th:if="${page.pageNum!=num}" th:href="@{'/employee/page/'+${num}}" th:text="${num} "></a> </span> <span th:if="${page.hasNextPage}"> <a th:href="@{'/employee/page/'+${page.nextPage}}">下一页</a> <a th:href="@{'/employee/page/'+${page.pages}}">末页</a> </span> </td> </tr> </table> </body> </html>
③访问测试分页功能
localhost:8080/employee/page/1
