文件上傳下載相關處理

1.  byte[] 轉換爲 MutipartFile

公司網絡區別外網和內網，文件由外網上傳，保存到數據庫，數據庫存儲的二進制文件。內網通過數據庫查詢獲取該文件信息上傳到內部文件服務器上，故用到該轉換方式：

byte[] bytes;
InputStream fis = new ByteArrayInputStream(bytes);
String fileName = "xxx.jpg";
DiskFileItemFactory diskFactory = new DiskFileItemFactory();
DiskFileItem fileItem = (DiskFileItem)diskFactory .createItem("file",mediaType.ALL_VALUE,fileName);
OutputStream fos = fileItem.getOutputStream();
IOUtils.copy(fis,fos);
MultipartFile multipartFile = new ConmonsMultipartFile(fileItem);

2.文件打包下載

FileZip.java

public class FileZip{

    private String chName;//文件名
    private File srcFile; //文件

}

public void downloadForZip(HttpServletResponse response){
    resonse.setContentType("application/octet-stream");
    resonse.addHeader("Content-Disposition","attachment;filename*=UTF-8"+URLEncoder.encode(zipNname)+".zip");
    
    try(OutputStream out =response.getOutputStream();ZipOutputStream zos = new ZipOutputSteam(out)){
        for(FileZip fileZip:fileZips){
            byte[] buf = new byte[2*1024]
            File srcFile = fileZip.getSrcFile();
            zos.putNextEntry(new ZipEntry(fileZip.getChName()));
            int len;
            try(FileInputStream in = new FileInputSteam(srcFile)){
                while((len=in.read(buf)) !=-1 ){
                    zos.write(buf,0,len);
                }
                zos.closeEntry();
            }catch(Exception e){
            
            }

        }
    
    }catch(Excption e){
    
    }



}