package com.iformall.utils;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;

/**
 * @author luozukai
 * 文件下载
 * @date 2019/2/13 15:32
 */
public class DownFileUtil {

    public static void downFile(String filePath,String exportFileName, HttpServletResponse response,
                         HttpServletRequest req) throws IOException {
        response.reset();
        response.setContentType("bin");
        String agent = req.getHeader("user-agent");
        if (agent.contains("Firefox")) {
            response.setHeader("Content-disposition",
                    "attachment; filename="
                            + new String(exportFileName.getBytes("GB2312"),
                            "ISO-8859-1"));
        } else {
            response.setHeader("Content-disposition",
                            "attachment; filename="
                                    + java.net.URLEncoder.encode(exportFileName,
                                    "UTF-8"));
        }
        // 循环取出流中的数据
        byte[] b = new byte[1024];
        int len;
        InputStream inStream = new FileInputStream(filePath);
        while ((len = inStream.read(b)) > 0)
            response.getOutputStream().write(b, 0, len);
        inStream.close();
    }

    public static void downLoadFromUrl(String urlStr, String fileName, String savePath) throws IOException {
        URL url = new URL(urlStr);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        //设置超时间为3秒
        conn.setConnectTimeout(3 * 1000);
        //防止屏蔽程序抓取而返回403错误
        conn.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");

        //得到输入流
        InputStream inputStream = conn.getInputStream();
        //获取自己数组
        byte[] getData = readInputStream(inputStream);

        //文件保存位置
        File saveDir = new File(savePath);
        if (!saveDir.exists()) {
            saveDir.mkdir();
        }
        File file = new File(saveDir + File.separator + fileName);
        FileOutputStream fos = new FileOutputStream(file);
        fos.write(getData);
        if (fos != null) {
            fos.close();
        }
        if (inputStream != null) {
            inputStream.close();
        }


        System.out.println("info:" + url + " download success");

    }

    public static byte[] readInputStream(InputStream inputStream) throws IOException {
        byte[] buffer = new byte[1024];
        int len = 0;
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        while ((len = inputStream.read(buffer)) != -1) {
            bos.write(buffer, 0, len);
        }
        bos.close();
        return bos.toByteArray();
    }

}
