@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 = Thread.currentThread().getContextClassLoader()

                    .getResource("").getPath()

                    + "download";//这个download目录为啥建立在classes下的

            InputStream inputStream = new FileInputStream(new File(path

                    + File.separator + 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;

    }

package com.clj.test.down.util;  

import java.io.File;

import java.io.IOException;  

import org.apache.commons.io.FileUtils;

import org.springframework.context.annotation.Scope;

import org.springframework.http.HttpHeaders;

import org.springframework.http.HttpStatus;

import org.springframework.http.MediaType;

import org.springframework.http.ResponseEntity;

import org.springframework.stereotype.Component;

import org.springframework.web.bind.annotation.RequestMapping;  

/**

 * <一句话功能简述>

 * <功能详细描述>

 *

 * @author  Administrator

 * @version  [版本号, 2014年3月7日]

 * @see  [相关类/方法]

 * @since  [产品/模块版本]

 */

@Component

@Scope("prototype")

@RequestMapping("/downloadFile")

public class DownloadAction

{  

    @RequestMapping("download")

    public ResponseEntity<byte[]> download() throws IOException {

        String path="D:\\workspace\\.metadata\\.plugins\\org.eclipse.wst.server.core\\tmp0\\wtpwebapps\\springMVC\\WEB-INF\\upload\\图片10（定价后）.xlsx";

        File file=new File(path);

        HttpHeaders headers = new HttpHeaders();

        String fileName=new String("你好.xlsx".getBytes("UTF-8"),"iso-8859-1");//为了解决中文名称乱码问题

        headers.setContentDispositionFormData("attachment", fileName);

        headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);

        return new ResponseEntity<byte[]>(FileUtils.readFileToByteArray(file),

                                          headers, HttpStatus.CREATED);

    }

}