SpringMvc文件上传和下载

 1 <!-- 文件上传的配置 -->  
 2 <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">     
 3        <!-- 指定所上传文件的总大小不能超过200KB。注意maxUploadSize属性的限制不是针对单个文件，而是所有文件的容量之和 -->     
 4        <property name="maxUploadSize" value="200000"/>     
 5    </bean>     
 6        
 7    <!-- 该异常是SpringMVC在检查上传的文件信息时抛出来的，而且此时还没有进入到Controller方法中 -->     
 8    <bean id="exceptionResolver" class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">     
 9        <property name="exceptionMappings">     
10            <props>     
11                <!-- 遇到MaxUploadSizeExceededException异常时，自动跳转到WebContent目录下的error.jsp页面 -->     
12                <prop key="org.springframework.web.multipart.MaxUploadSizeExceededException">error</prop>     
13            </props>     
14        </property>     
15    </bean>  

1 <form action="upload.do" method="post" enctype="multipart/form-data">  
2          文件1: <input type="file" name="myfiles"/><br/>     
3           文件2: <input type="file" name="myfiles"/><br/>     
4           文件3: <input type="file" name="myfiles"/><br/>     
5         <input type="submit" value="上传">  
6 </form>  

 1 @RequestMapping("/upload.do")  
 2     public String upload(@RequestParam MultipartFile[] myfiles,HttpServletRequest request) throws IOException {  
 3         for(MultipartFile file : myfiles){     
 4             //此处MultipartFile[]表明是多文件,如果是单文件MultipartFile就行了  
 5             if(file.isEmpty()){   
 6                 System.out.println("文件未上传!");  
 7             }  
 8             else{  
 9                 //得到上传的文件名  
10                 String fileName = file.getOriginalFilename();  
11                 //得到服务器项目发布运行所在地址  
12                 String path1 = request.getSession().getServletContext().getRealPath("image")+File.separator;  
13                 //  此处未使用UUID来生成唯一标识,用日期做为标识  
14                 String path = path1+ new SimpleDateFormat("yyyyMMddHHmmss").format(new Date())+ fileName;  
15                 //查看文件上传路径,方便查找  
16                 System.out.println(path);  
17                 //把文件上传至path的路径  
18                 File localFile = new File(path);  
19                 file.transferTo(localFile);  
20                 }  
21             }  
22         return "uploadSuccess";  
23     }  

<a href="download.do?fileName=2016082312271111111.jpg">下载</a>  

@RequestMapping("/download")  
    public String download(String fileName, HttpServletRequest request,  
            HttpServletResponse response) {  
        response.setCharacterEncoding("utf-8");  
        response.setContentType("multipart/form-data");  
        response.setHeader("Content-Disposition", "attachment;fileName="  
                + fileName);  
        try {  
            String path = request.getSession().getServletContext().getRealPath  
                    ("image")+File.separator;  
            InputStream inputStream = new FileInputStream(new File(path  
                    + fileName));  
  
            OutputStream os = response.getOutputStream();  
            byte[] b = new byte[2048];  
            int length;  
            while ((length = inputStream.read(b)) > 0) {  
                os.write(b, 0, length);  
            }  
  
             // 这里主要关闭。  
            os.close();  
  
            inputStream.close();  
        } catch (FileNotFoundException e) {  
            e.printStackTrace();  
        } catch (IOException e) {  
            e.printStackTrace();  
        }  
            //  返回值要注意，要不然就出现下面这句错误！  
            //java+getOutputStream() has already been called for this response  
        return null;  
    }