package com.siwei.apply.utils;

import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.nio.file.Files;
import java.util.ArrayList;
import java.util.zip.ZipOutputStream;

/**
 * 下载工具类
 */
public class DownloadUtils {
    /**
     * 将所有文件打包成zip并下载
     *
     * @param response
     * @param files    文件地址集合
     * @param filename zip的文件名
     */
    public static void DownloadZip(HttpServletResponse response, ArrayList<String> files, String filename) {
        ZipOutputStream zipOutputStream = null;
        try {
            response.setHeader("Content-Disposition", "attachment;filename=" + new String((filename + ".zip").getBytes("UTF-8"), "ISO-8859-1"));  // 需要编z码否则中文乱码
            response.setContentType("application/zip;charset=utf-8");
            response.setCharacterEncoding("UTF-8");
            // 直接返回zip输出流不生成临时文件。
            zipOutputStream = new ZipOutputStream(response.getOutputStream());
            for (String path : files) {
                File file = new File(path);
                if (file.exists()) {
                    byte[] readAllBytes = Files.readAllBytes(file.toPath());
                    org.apache.tools.zip.ZipEntry zipEntry = new org.apache.tools.zip.ZipEntry(file.getName());
                    zipOutputStream.putNextEntry(zipEntry);
                    zipOutputStream.write(readAllBytes);
                }
            }
            zipOutputStream.close();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                zipOutputStream.close();
            } catch (Exception e) {

            }
        }
    }
}