介面程式碼

import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import java.io.*;

@RestController
@RequestMapping(value 
 
= "/file")
@Slf4j
public class FileController {

    /**
     * windows下的檔案路徑
     */
    private final String File_PATH = "F:/upload/temp";

    @PostMapping(value = "/upload")
    String uploadFileBufferToLocal(MultipartFile file) {

            //將檔案緩衝到本地
            boolean localFile = createLocalFile(File_PATH, file);
            
 
if(!localFile){
                log.error("Create local file failed!");
                return "Create local file failed!";
            }
            log.info("Create local file successfully");

        return "Create local file successfully";
    }

    /**
     * 通過上傳的檔名，緩衝到本地，後面才能解壓、驗證
     * @param
 
 filePath 臨時緩衝到本地的目錄
     * @param file
     */
    public boolean createLocalFile(String filePath,MultipartFile file) {
        File localFile = new File(filePath);
        //先建立目錄
        localFile.mkdirs();

        String originalFilename = file.getOriginalFilename();
        String path = filePath+"/"+originalFilename;

        log.info("createLocalFile path = {}", path);

        localFile = new File(path);
        FileOutputStream fos = null;
        InputStream in = null;
        try {

            if(localFile.exists()){
                //如果檔案存在刪除檔案
                boolean delete = localFile.delete();
                if (delete == false){
                    log.error("Delete exist file \"{}\" failed!!!",path,new Exception("Delete exist file \""+path+"\" failed!!!"));
                }
            }
            //建立檔案
            if(!localFile.exists()){
                //如果檔案不存在，則建立新的檔案
                localFile.createNewFile();
                log.info("Create file successfully,the file is {}",path);
            }

            //建立檔案成功後，寫入內容到檔案裡
            fos = new FileOutputStream(localFile);
            in = file.getInputStream();
            byte[] bytes = new byte[1024];

            int len = -1;

            while((len = in.read(bytes)) != -1) {
                fos.write(bytes, 0, len);
            }

            fos.flush();
            log.info("Reading uploaded file and buffering to local successfully!");
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            return false;
        } catch (IOException e) {
            e.printStackTrace();
            return false;
        }finally {
            try {
                if(fos != null) {
                    fos.close();
                }
                if(in != null) {
                    in.close();
                }
            } catch (IOException e) {
                log.error("InputStream or OutputStream close error : {}", e);
                return false;
            }
        }

        return true;
    }
}

過程是：

首先介面接收檔案；

建立將要緩衝檔案的目錄，存在指定目錄就不建立；

判斷該目錄是否有重複的檔名，如果有，先刪除再生成，如果沒有，就生成檔案；

然後將通過檔案流以每次1024bytes寫入指定目錄的檔案；

最後關閉流。