SpringMVC学习指南【笔记7】上传文件
Spring MVC中处理已上传文件的两种方法，一是利用CommonsFileUpload元件，二是利用Servlet3本地文件上传特性。
客户端编程
为了上传文件，必须将html表格的enctype属性值设为multipart/form-data
<form action="action" enctype="multipart/form-data" method="post"> select a file<input type="file" name="fieldName" /><!--这个input标签会显示成一个按钮，点击时，会打开一个对话框，用来选择文件--> <input type="submit" value="upload" /> </form> <!--上传多个文件,以下3行代码都可以--> <input type="file" name="fieldName" multiple /> <input type="file" name="fieldName" multiple="multiple" /> <input type="file" name="fieldName" multiple="" />
MultipartFile接口
org.springframework.web.multipart.MultipartFile
例如，Product这个实体类要添加多个文件的属性，List<MultipartFile> files;
@RequestMapping(value="product_save") public String productSave(HttpServletRequest servletRequest, @ModelAttribute Product product, BindingResult bindingResult,Model model){ List<MultipartFile> files = product.getFiles(); List<String> filesName = new ArrayList<String>(); if(null != files && files.size() > 0){ for(MultipartFile multipartFile : files){ String fileName = multipartFile.getOriginalFilename(); filesName.add(fileName); File file = new File(servletRequest.getServletContext().getRealPath("/file"), fileName); try { multipartFile.transferTo(file); // 保存已上传文件 } catch (IllegalStateException | IOException e) { e.printStackTrace(); } } } // save product here model.addAttribute("product", product); return "productDetails"; }
JSP页面
<form:form commandName="product" action="product_save" method="post" enctype="multipart/form-data"> <fieldset> <p> <label for="name">product name:</label> <form:input id="name" path="name" cssErrorClass="error" /> <form:errors path="name" cssErrorClass="error" /> </p> <p> <label for="file">product file:</label> <input type="file" name="files[0]" /> </p> </fieldset> </form:form>
处理已上传的文件的两种方法
第一种：利用Common FileUpload元件
Spring MVC的配置文件，这里multipartResolver引用的是CommonMultipartResolver
<?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:p="http://www.springframework.org/schema/p" 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 http://www.springframework.org/schema/context/springcontext.xsd "> <!-- 扫描目标包中的类 --> <context:component-scan base-package="com.xsl.controller" /> <context:component-scan base-package="com.xsl.service" /> <!-- 注册用于支持基于注解的控制器的请求处理方法的bean对象 --> <mvc:annotation-driven /> <!-- 指示Spring MVC哪些静态资源需要单独处理，不需要dispatcher servlet --> <mvc:resources mapping="/css/**" location="/css/" /> <mvc:resources mapping="/*.html" location="/" /> <mvc:resources mapping="/image/**" location="/image/" /> <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/jsp/" /> <property name="suffix" value=".jsp" /> </bean> <bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource"> <property name="basename" value="/WEB-INF/resource/messages" /> </bean> <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonMultipartResolver"> </bean> </beans>
第二种：利用Servlet3本地文件上传特性
给部署描述符(web.xml)中的servlet声明赋值，使一个Servlet变成一个MultipartConfig Servlet，以下代码与用@MultipartConfig给DispatcherServlet进行标注的效果一样，关键是multipart-config这个元素
<?xml version="1.0" encoding="UTF-8" ?> <web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> <servlet> <servlet-name>springmvc</servlet-name> <servlet-class> org.springframework.web.servlet.DispatcherServlet </servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/config/springmvc-config.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> <multipart-config> <max-file-size>20848820</max-file-size> <max-request-size>418018841</max-request-size> <file-size-threshold>1048576</file-size-threshold> </multipart-config> </servlet> <servlet-mapping> <servlet-name>springmvc</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> </web-app>
Spring MVC配置文件，这里multipartResolver引用的是StandardServletMultipartResolver
<?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:p="http://www.springframework.org/schema/p" 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 http://www.springframework.org/schema/context/springcontext.xsd "> <!-- 扫描目标包中的类 --> <context:component-scan base-package="com.xsl.controller" /> <context:component-scan base-package="com.xsl.service" /> <!-- 注册用于支持基于注解的控制器的请求处理方法的bean对象 --> <mvc:annotation-driven /> <!-- 指示Spring MVC哪些静态资源需要单独处理，不需要dispatcher servlet --> <mvc:resources mapping="/css/**" location="/css/" /> <mvc:resources mapping="/*.html" location="/" /> <mvc:resources mapping="/image/**" location="/image/" /> <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/jsp/" /> <property name="suffix" value=".jsp" /> </bean> <bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource"> <property name="basename" value="/WEB-INF/resource/messages" /> </bean> <bean id="multipartResolver" class="org.springframework.web.support.StandardServletMultipartResolver"> </bean> </beans>
