这个SpringMVC没什么关系吧，我在jsp中做过一个图片的下载，你可能要修改下代码

response.setContentType("application/x-download");   
	 //application.getRealPath("/main/mvplayer/CapSetup.msi");获取的物理路径   
	 String filedownload = request.getRealPath("/")+"/organization/img/"+"组织架构图.png";   
 	 String filedisplay = "组织架构图.png";   
  	 filedisplay = URLEncoder.encode(filedisplay,"UTF-8");   
  	 response.addHeader("Content-Disposition","attachment;filename=" + filedisplay);   
  
	  java.io.OutputStream outp = null;   
	  java.io.FileInputStream in = null;   
	  try   
	  {   
	  outp = response.getOutputStream();   
	  in = new java.io.FileInputStream(filedownload);   
	  
	  byte[] b = new byte[1024];   
	  int i = 0;   
	  
	  while((i = in.read(b)) > 0)   
	  {   
	 	 outp.write(b, 0, i);   
	  }   
		outp.flush();   
		//要加以下两句话，否则会报错   
		//java.lang.IllegalStateException: getOutputStream() has already been called for this respons
		out.clear();   
		out = pageContext.pushBody();   
		}   
	  catch(Exception e)   
	  {   
	  System.out.println("Error!");   
	  e.printStackTrace();   
	  }   
	  finally   
	  {   
		  if(in != null)   
		  {   
			  in.close();   
			  in = null;   
		  } 
		  
		  if(in != null)   
		  {   
			  in.close();   
			  in = null;   
		  }  
	  }





 

//下载方法
	private void downloadFile(File file){
		String fileName = file.getName();
		try {
			fileName = URLEncoder.encode(fileName, "UTF-8");
		} catch (UnsupportedEncodingException e1) {
			e1.printStackTrace();
		}
		contextPvd.getResponse().setContentType("application/zip");
		contextPvd.getResponse().addHeader("Content-Disposition", "attachment;filename=" + fileName);
		OutputStream outp = null;
		FileInputStream in = null;
		try {
			outp = contextPvd.getResponse().getOutputStream();
			in = new FileInputStream(file);
			byte[] b = new byte[1024];
			int i = 0;

			while ((i = in.read(b)) > 0) {
				outp.write(b, 0, i);
			}
			outp.flush();
		} catch (Exception e) {
			//log.error("", e);
		} finally {
			if (in != null) {
				try {
					in.close();
					in = null;
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			if (outp != null) {
				try {
					outp.close();
					outp = null;
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
	}