package com.zsf.util;

import org.apache.commons.io.FileUtils;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.multipart.MultipartFile;

 
import javax.servlet.http.HttpServletRequest;
import java.io.File;
import java.io.IOException;

public class FileLoadUtil{

    /**
     * 圖片上傳
     * @param request
     * @param file
     */
    public static String upload(HttpServletRequest request, MultipartFile file){

        //重新定義文件名防止重名被替換
        String fileName = UUIDUtil.createUUID();
        
 
//獲取文件上傳的路徑
        String path = request.getServletContext().getRealPath("/images");

        //如果上傳目錄不存在，則創建出來
        File dir = new File(path);
        if(!dir.exists()){
            dir.mkdir();
        }
        //獲取上傳的文件名(也可以自定義)
        //String fileName = file.getOriginalFilename();
        //構建一個完整文件信息(路徑 + 文件名)
 

        File fileMessage = new File(dir.getAbsolutePath() + "/" + fileName);
        try {
            //執行上傳,只需要調用transferTo方法即可
            file.transferTo(fileMessage);
            //將文件名放入model中
//            model.addAttribute("fileName", fileName);
        } catch (IOException e) {
            e.printStackTrace();
            throw new RuntimeException("上傳圖片失敗");
        }
        return fileName;
    }

    /**
     * 圖片下載
     * @param fileName
     * @param request
     * @return
     */
    public static ResponseEntity<byte[]> downLoad(String fileName,HttpServletRequest request){
        //獲取下載路徑
        String path = request.getServletContext().getRealPath("/images");
        //構建下載文件
        File file = new File(path + "/" + fileName);
        //創建HttpHeaders設置響應頭信息
        HttpHeaders headers = new HttpHeaders();
        try {
            //設置在響應頭中的文件名稱，這裏進行重新編碼，防止中文亂碼
            String headerFileName = new String(fileName.getBytes("UTF-8"), "ISO-8859-1");
            //設置內容以附件的方式下載
            headers.setContentDispositionFormData("attachment", headerFileName);
            //設置相應類型為application/octet-stream
            headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
            //創建ResponseEntity對象
            ResponseEntity<byte[]> entity = new ResponseEntity<>(FileUtils.readFileToByteArray(file), headers, HttpStatus.CREATED);
            return entity;
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException("文件下載失敗");
        }
    }
}

基於spring的文件上傳下載