springmvc 之 文件上传

1. 新建web项目
2. 导入 jar 包，文件上传需要导入 commons-io, commons-fieupload.
3. 配置 web.xml

   <!-- springmvc前端控制器配置 -->
     <servlet>
         <servlet-name>mvc</servlet-name>
         <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
         <init-param>
             <param-name>contextConfigLocation</param-name>
             <param-value>classpath:mvc.xml</param-value>
         </init-param>
         <load-on-startup>1</load-on-startup>
     </servlet>
     <servlet-mapping>
         <servlet-name>mvc</servlet-name>
         <url-pattern>*.do</url-pattern>
     </servlet-mapping>

   注意：servlet-mapping如果为 / 时，要拦截所要的请求。

4. 编写文件上传处理器

   @Controller
   public class FileUploadController {
       @RequestMapping("/upload")
       public String fileupload(@RequestParam("file")CommonsMultipartFile file,HttpServletRequest req){
           String path = req.getRealPath("/upload");
           //获取原始文件名
           String fileName = file.getOriginalFilename();
           try {
               InputStream is = file.getInputStream();
               OutputStream os = new FileOutputStream(new File(path,fileName));
               byte[] buffer = new byte[400];
               int len=0;
               while((len=is.read(buffer))!=-1)
                   os.write(buffer, 0, len);
               os.close();
               is.close();
           } catch (FileNotFoundException e) {
               e.printStackTrace();
           } catch (IOException e) {
               e.printStackTrace();
           }
           return "forward:/success.jsp";
       }
   }

5. 编写 springmvc配置文件，需要配置MultipartResolver

   <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"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       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/spring-context.xsd 
           http://www.springframework.org/schema/mvc
           http://www.springframework.org/schema/mvc/spring-mvc.xsd">
       <bean id="jspViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
           <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
           <property name="prefix" value="/"/>
           <property name="suffix" value=".jsp"/>
       </bean>
       <!-- 多媒体解析器 -->
       <bean id="multipartResolver"
           class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
           <property name="maxUploadSize" value="100000000"/>
       </bean>
       <mvc:annotation-driven/>
       <context:component-scan base-package="cn.wh.controller"/>
   </beans>

6. 编写 jsp 页面

   <form action="upload.do" method="post" enctype="multipart/form-data">
          文件:<input type="file" name="file"/><input type="submit" value="上传"/>
      </form>

   请求路径不能和上传的目录一致