文件上传和下载（持续更新中）

#上传
##单文件上传

public class FileUtils {
	JsonObject jsonObject = new JsonObject();
	public static Object fileUpload(@RequestParam("multipartFile")MultipartFile multipartFile) {
		if(！multipartFile.isEmpty())｛
			String fileName = multipartFile.getOriginalFilename();
			String path = "D:/testFile/";
			File targetFile = new File(path+fileName);
			if (!targetFile.exists()) {
                targetFile.mkdirs();
            }
			
			try {
                multipartFile.transferTo(targetFile);
				jsonObject.put("code",1);
				jsonObject.put("message","上传成功");
            } catch (Exception e) {
                e.printStackTrace();
				jsonObject.put("code",0);
				jsonObject.put("message","该文件不存在");
            }finally{
				return jsonObject;
			}
			//这里除了transferTo方法，也可以用字节流的方式上传文件，但是字节流比较慢，所以还是建议用transferTo
//            try {
//                //获取输出流
//                OutputStream os=new FileOutputStream(path);
//                //获取输入流 CommonsMultipartFile 中可以直接得到文件的流
//                InputStream is=multipartFile.getInputStream();
//                byte[] buffer= new byte[1024];
//                int len = is.read(buffer);
//                while(len!=-1){
//                    os.write(buffer, 0, len);
//                }
//                os.flush();
//                os.close();
//                is.close();
//            } catch (FileNotFoundException e) {
//                // TODO Auto-generated catch block
//                e.printStackTrace();
//            }
			
		｝else{
			jsonObject.put("code",0);
			jsonObject.put("message","该文件不存在");
		}
		return jsonObject;
	}
}
#利用MultipartHttpServletRequest来解析request中的文件
public static filesUpload(HttpServletRequest request) {
	CommonsMultipartResolver resolver = new CommonsMultipartResolver(request.getSession().getServletContext());
	if(resolver.isMultipart(request)){
		MultipartHttpServletRequest multiRequest = (MultipartHttpServletRequest)request;
		MultipartFile file = multiRequest.getFile("file");
		if(file.isEmpty()){
			
		}else{
			
		}
	}else{
		jsonObject.put("code",0);
		jsonObject.put("message","该文件不存在");
	}
	return jsonObject;
}
#文件下载列表
public Object getList() {
	String path = "D:/testFile";
	File directory = new File(path);
	String[] fileNames = directory.list();
}


#文件下载
public static fileDownload(HttpServletRequest request,HttpServletResponse response) {
	
	String fileName = request.getParameter("fileName"); 
	File file = new File("D:/testFile/"+fileName);
	
	response.reset();
	response.setContentType("application/octet-stream;charset=utf-8");
	response.addHeader("Content-Length",file.length());
	response.addHeader("Content-Disposition","attachment;filename="+new String(fileName.getBytes("utf-8"),"gb2312"));
	BufferedInputStream bis = new BufferedInputStream(new FileInputStream(file));
	BufferedOutputStream bos = new BufferedOutputStream(response.getOutputStream());
	//IOUtils.copy(inputStream, outputStream);
	Byte[] buf = new Byte[1024];
	int len = -1;
	while((len = bis.read(buf))!=-1){
		bos.write(buf,0,len);
	}
	bis.close();
	bos.flush();
	bos.close();
}
#没有多文件下载

图片上传：https://blog.csdn.net/weixin_41888813/article/details/85043969

来源：CSDN

作者：LY破晓

链接：https://blog.csdn.net/qq_40321119/article/details/103773061