<!-- fileUpload 解析上传的文件用到的jar -->
<dependency>
    <groupId>commons-fileupload</groupId>
    <artifactId>commons-fileupload</artifactId>
    <version>1.3.1</version>
</dependency>
<dependency>
    <groupId>commons-io</groupId>
    <artifactId>commons-io</artifactId>
    <version>2.4</version>
</dependency>

<form action="upload" method="post" enctype="multipart/form-data">
    <table>
        <tr>
            <td>用户名</td>
            <td><input type="text" name="username"></td>
        </tr>
        <tr>
            <td>用户密码</td>
            <td><input type="password" name="password"></td>
        </tr>
        
        <tr>
            <td>用户图像</td>
            <td><input type="file" name="userface"></td>
        </tr>
        <tr>
            <td><input type="submit" value="注册"></td>
        </tr>
    </table>
</form>

/**
 * 文件上传案例
 * @author dpb【波波烤鸭】
 *
 */
@Controller
public class UserController {

    /**
     * 上传的数据通过MultipartFile对象接收
     * @param username
     * @param password
     * @param userface
     * @throws Exception
     * @throws IOException
     */
    @RequestMapping("/upload")
    @ResponseBody
    public void upload(String username,String password
            ,MultipartFile userface) throws Exception, IOException{
        System.out.println(username+","+password);
        userface.transferTo(new File("c:/tools/","123.png"));
    }
    
}

    <bean class="org.springframework.web.multipart.commons.CommonsMultipartResolver"
        id="multipartResolver" >
        <!-- 设置上传文件信息参数 -->
        <!-- 设置文件上传的最大尺寸 -->
        <property name="maxUploadSize">
            <value>5242880</value>
        </property>
    </bean>

@RequestMapping("/testHttpMessageDown")
public ResponseEntity<byte[]> download(HttpServletRequest request) throws IOException {
    // 需要下载的文件
    File file = new File("E://123.jpg");
    byte[] body = null;
    InputStream is = new FileInputStream(file);
    body = new byte[is.available()];
    is.read(body);
    HttpHeaders headers = new HttpHeaders();
    headers.add("Content-Disposition", "attchement;filename=" + file.getName());
    HttpStatus statusCode = HttpStatus.OK;
    ResponseEntity<byte[]> entity = new ResponseEntity<byte[]>(body, headers, statusCode);
    return entity;
}

@RequestMapping("/exportExcel")
public void exportExcel(HttpServletRequest request,HttpServletResponse response) throws IOException{
    File file = new File("d://owned.xls");
    //设置响应头和客户端保存文件名
    response.setCharacterEncoding("utf-8");
    response.setContentType("multipart/form-data");
    response.setHeader("Content-Disposition", "attachment;fileName=" + file.getName());
    try {
        //打开本地文件流
        InputStream inputStream = new FileInputStream(file);
        //激活下载操作
        OutputStream os = response.getOutputStream();
        //循环写入输出流
        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 (Exception e){
        
        throw e;
    }
}

 <!-- 防止资源文件被spring MVC拦截 -->
    <servlet-mapping>
        <servlet-name>default</servlet-name>
        <url-pattern>*.jpg</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>default</servlet-name>
        <url-pattern>*.js</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>default</servlet-name>
        <url-pattern>*.css</url-pattern>
    </servlet-mapping>