服务器传输图片到客户端，有时候是直接下载，有时候是类似src=’请求路径’

其主要区别在于

res.setContentType("img/jpg");
res.setHeader("Content-Disposition", "attachment;filename="+fileName);
 

加了这两行之后就是下载 一个是格式，一个是文件名字

另外附上下载图片代码:

@ResponseBody
@ request Mapping(value = "/downloadFile", method = { RequestMethod.GET, RequestMethod.POST })
public void downloadFile(HttpServletRequest request, HttpServletResponse res) {
logger.info("download file ...");
String fileName = request.getParameter("fileName");
File file = new File(fileUploadPath + fileName);
if (!file. exists ()) {
logger.error("resource file not exists.");
}
BufferedInputStream bis = null;
BufferedOutputStream bos = null;
try {
res.setContentType("img/jpg");
res.setHeader("Content-Disposition", "attachment;filename="+fileName);
bis = new BufferedInputStream(new FileInputStream(file));
bos = new BufferedOutputStream(res.getOutputStream());
 byte [] bys = new byte[1024];
int len = 0;
while ((len = bis.read(bys)) != -1) {
bos.write(bys, 0, len);
}
logger.info("downloadComplete...");
} catch (IOException e) {
e.printStackTrace();
logger.error("downloadError", e);
} finally {
try {
bos. close ();
bis.close();
} catch (IOException e) {
}
}
}