Java如何將MultipartFile轉爲File

MultipartFile multiFile = new MultipartFile(); //前端傳過來的文件對象

String fileName = multiFile.getOriginalFilename();
String prefix = fileName.substring(fileName.lastIndexOf("."));

File file = null;
try {

     file = File.createTempFile(fileName, prefix);
     multiFile.transferTo(file);
} catch (Exception e) {
     e.printStackTrace();
            
} finally {
     // 操作完上面的文件 需要刪除在根目錄下生成的臨時文件
     File f = new File(file.toURI());
     f.delete();
}

以上方法如果涉及跨域很有可能不能使用，建議使用以下方法

 //調用
 File file = null;
 try {
      //將MultipartFile轉爲File
      file = multipartFileToFile(multiFile);
     } catch (Exception e) {
          e.printStackTrace();
          result.setMsg("上傳失敗，請檢查文件格式再次嘗試");
          result.setValid(false);
          return result;
     } finally {
          deleteTempFile(file);
     }

//工具類
import org.springframework.web.multipart.MultipartFile;

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * @Auther: QiShuai
 * @Date: 2020/4/8 10:58
 * @Description:
 */
public class MultipartFileToFile {
    /**
     * MultipartFile 轉 File
     *
     * @param file
     * @throws Exception
     */
    public static File multipartFileToFile(MultipartFile file) throws Exception {

        File toFile = null;
        if (file.equals("") || file.getSize() <= 0) {
            file = null;
        } else {
            InputStream ins = null;
            ins = file.getInputStream();
            toFile = new File(file.getOriginalFilename());
            inputStreamToFile(ins, toFile);
            ins.close();
        }
        return toFile;
    }

    //獲取流文件
    private static void inputStreamToFile(InputStream ins, File file) {
        try {
            OutputStream os = new FileOutputStream(file);
            int bytesRead = 0;
            byte[] buffer = new byte[8192];
            while ((bytesRead = ins.read(buffer, 0, 8192)) != -1) {
                os.write(buffer, 0, bytesRead);
            }
            os.close();
            ins.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 刪除本地臨時文件
     * @param file
     */
    public static void deleteTempFile(File file) {
        if (file != null) {
            File del = new File(file.toURI());
            del.delete();
        }
    }
}