import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;

import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

/**
 * @author wx
 * @date 2020/10/29 5:19 下午
 */
public class FileZipUtil {

  private static void handlerFile(ZipOutputStream zip, File file, String dir) throws Exception {
    //如果當前的是文件夾，則進行進一步處理
    if (file.isDirectory()) {
      //得到文件列表信息
      File[] fileArray = file.listFiles();
      if (fileArray == null) {
        return;
      }
      //將文件夾添加到下一級打包目錄
      zip.putNextEntry(new ZipEntry(dir + "/"));
      dir = dir.length() == 0 ? "" : dir + "/";
      //遞歸將文件夾中的文件打包
      for (File f : fileArray) {
        handlerFile(zip, f, dir + f.getName());
      }
    } else {
      //當前的是文件，打包處理
      //文件輸入流
      BufferedInputStream bis = new BufferedInputStream(new FileInputStream(file));
      ZipEntry entry = new ZipEntry(dir);
      zip.putNextEntry(entry);
      zip.write(FileUtils.readFileToByteArray(file));
      IOUtils.closeQuietly(bis);
      zip.flush();
      zip.closeEntry();
    }
  }

  private static byte[] createZip(String sourceFilePath) throws Exception{
    ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
    ZipOutputStream zip = new ZipOutputStream(outputStream);
    //將目標文件打包成zip導出
    File file = new File(sourceFilePath);
    handlerFile(zip, file,"");
    IOUtils.closeQuietly(zip);
    return outputStream.toByteArray();
  }


  public static void exportZip(HttpServletResponse response, String sourceFilePath) {
  //文件名以時間戳作為前綴
    SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmss");
    String filePrefix = sdf.format(new Date());
    String downloadName = filePrefix + ".zip";
    //將文件進行打包下載
    try {
      OutputStream out = response.getOutputStream();
      //接收壓縮包字節
      byte[] data = createZip(sourceFilePath);
      response.reset();
      response.addHeader("Access-Control-Allow-Origin", "*");
      response.setHeader("Access-Control-Expose-Headers", "*");
      response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + downloadName);
      response.addHeader("Content-Length", "" + data.length);
      response.setContentType("application/octet-stream;charset=UTF-8");
      IOUtils.write(data, out);
      out.flush();
      out.close();
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}

 @GetMapping("/exportFile")
  public Result exportFile(HttpServletResponse response) {
    //第二個參數為：要壓縮文件的地址
    FileZipUtil.exportZip(response, "/Users/Downloads");
  }