java文件下载

import org.junit.Test;

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;

/**
 * @Author: liuzhihu
 * @Date: 2019/6/10 8:55
 */
public class DownLoadTest {


    /**
     * 从网络Url中下载文件
     * @param urlStr
     * @param fileName
     * @param savePath
     * @throws IOException
     */
    public static void downLoadFromUrl(String urlStr, String fileName, String savePath, String toekn) 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)");
        conn.setRequestProperty("lfwywxqyh_token", toekn);

        //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");

    }


    /**
     * 从输入流中获取字节数组
     *
     * @param inputStream
     * @return
     * @throws IOException
     */
    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();
    }

    @Test
    public void t1() throws Exception {
        String token = "v32Eo2Tw+qWI/eiKW3D8ye7l19mf1NngRLushO6CumLMHIO1aryun0/Y3N3YQCv/TqzaO/TFHw4=";
        // String token="SiGBCH6QblUHs7NiouV09rL6uAA3Sv0cGicaSxJiC/78DoWIMzVbW6VCwwkymYsZaxndDkYqkm4=";
        downLoadFromUrl("https://inv.jss.com.cn/group4/M01/0E/09/wKj6yFz9vlWIPaY0AACMKy1-D_cAAJCwAPPMFwAAIxD248.pdf", "abc.pdf", "D:\\", token);
        System.out.println("下载完成");
    }
    
     //批量下载
    private void Download(List<String> listImgSrc) {
        try {
            //开始时间
            Date begindate = new Date();
            for (String url : listImgSrc) {
                //开始时间
                Date begindate2 = new Date();
                String imageName = url.substring(url.lastIndexOf("/") + 1, url.length());
                URL uri = new URL(url);
                InputStream in = uri.openStream();
                FileOutputStream fo = new FileOutputStream(new File("src/res/"+imageName));//文件输出流
                byte[] buf = new byte[1024];
                int length = 0;
                System.out.println("开始下载:" + url);
                while ((length = in.read(buf, 0, buf.length)) != -1) {
                    fo.write(buf, 0, length);
                }
                //关闭流
                in.close();
                fo.close();
                System.out.println(imageName + "下载完成");
                //结束时间
                Date overdate2 = new Date();
                double time = overdate2.getTime() - begindate2.getTime();
                System.out.println("耗时：" + time / 1000 + "s");
            }
            Date overdate = new Date();
            double time = overdate.getTime() - begindate.getTime();
            System.out.println("总耗时：" + time / 1000 + "s");
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("下载失败");
        }
    }
    
    
}