废话不说，直接上代码：文末有彩蛋。

package com.huqitong.spiderdanmu;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.text.NumberFormat;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.zip.InflaterInputStream;

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

import com.alibaba.fastjson.JSONObject;

public class SpiderAiqiyiDanMu {

    public static void main(String[] args) {
        String url = "http://www.iqiyi.com/v_19rrmm2vbk.html";
        List<String> res = getDanMu(url);
        for (String r : res) {
            System.out.println(r);
        }
    }

    public static List<String> getDanMu(String url) {
        //获取电影或者电视剧的tvId
        String res = httpGetRequest(url, false);
        String REGEX = "tvId:(.+?),";
        Pattern p = Pattern.compile(REGEX);
        Matcher m = p.matcher(res);
        String tvId = "";
        if (m.find()) {
            tvId = m.group(1);
        } else {
            return null;
        }
        // 根据tvId获取电影或者电视剧的详细信息。
        String infoUrl = "http://mixer.video.iqiyi.com/jp/mixin/videos/" + tvId;
        String info = httpGetRequest(infoUrl, false);
        info = info.replace("var tvInfoJs=", "");
        JSONObject jsonObject = JSONObject.parseObject(info);
        // 电影或电视剧专辑
        String albumId = jsonObject.getString("albumId");
        // 电影或电视剧频道
        String channelId = jsonObject.getString("channelId");
        // 电影或电视剧时长
        int duration = jsonObject.getIntValue("duration");
        return getDanMu(tvId, albumId, channelId, duration);
    }

    private static List<String> getDanMu(String tvId, String albumId, String channelId, int duration) {
        // 弹幕下载地址
        String IQIYI_GET_DANMU_URL = "http://cmts.iqiyi.com/bullet/%s/%s/%s_300_%s.z?rn=%s&business=danmu&is_iqiyi=true&is_video_page=true&tvid=%s&albumid=%s&categoryid=%s&qypid=01010021010000000000";
        List<String> danmus = new ArrayList<String>();
        // 根据电影或电视剧的时长计算出需要多少个批量弹幕请求，爱奇艺平均5分钟请求一次加载弹幕
        int page = duration / (60 * 5) + 1;
        for (int i = 1; i <= page; i++) {
            try {
                String t = "0000" + tvId;
                int length = t.length();
                String first = t.substring(length - 4, length - 2);
                String second = t.substring(length - 2);
                String rn = "0." + randomNum(16);
                String danmuUrl = String.format(IQIYI_GET_DANMU_URL, first, second, tvId, i, rn, tvId, albumId,
                        channelId);
                String res = httpGetRequest(danmuUrl, true);
                if (res != null) {
                    danmus.add(res);
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return danmus;
    }

    // httpClient 请求
    private static String httpGetRequest(String url, boolean needUnzip) {
        CloseableHttpClient httpClient = HttpClients.custom().build();
        HttpGet httpGet = new HttpGet(url);
        CloseableHttpResponse response = null;
        try {
            response = httpClient.execute(httpGet);
            HttpEntity entity = response.getEntity();
            if (entity != null) {
                if (needUnzip) {
                    return new String(decompress(entity.getContent()));
                }
                return EntityUtils.toString(entity);
            }
        } catch (Exception e) {
        } finally {
            try {
                response.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return null;
    }

    // 解压缩字节流
    private static byte[] decompress(InputStream is) {
        InflaterInputStream iis = new InflaterInputStream(is);
        ByteArrayOutputStream o = new ByteArrayOutputStream(1024);
        try {
            int i = 1024;
            byte[] buf = new byte[i];
            while ((i = iis.read(buf, 0, i)) > 0) {
                o.write(buf, 0, i);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return o.toByteArray();
    }

    // 构造随机参数
    private static String randomNum(double n) {
        double s = Math.pow(10, n - 1);
        double e = Math.pow(10, n) - 1;
        double res = Math.random() * (e - s) + s;
        NumberFormat nf = NumberFormat.getInstance();
        nf.setGroupingUsed(false);
        return nf.format(res);
    }
}

欢迎大家关注，阅读，点赞，评论我的职场连载小说:《程序猿生存指南》

或者青春校园小说 ：《青春在硬盘里灼烧》

或者来两个短篇感受一下画风：

《西二旗程序员杀人事件》

《一个三流写手的自我修养》