1. byte[] 转换为 MutipartFile
公司网络区别外网和内网，文件由外网上传，保存到数据库，数据库存储的二进制文件。内网通过数据库查询获取该文件信息上传到内部文件服务器上，故用到该转换方式：
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.文件打包下载
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){
}
}