链接：我的讲解视频https://www.bilibili.com/video/BV14e411Q7oG/
本文仅供学术用途

先上图

代码

爬虫核心

import com.alibaba.fastjson2.JSON;
import com.alibaba.fastjson2.JSONObject;
import com.gargoylesoftware.htmlunit.*;
import org.apache.commons.exec.CommandLine;
import org.apache.commons.exec.DefaultExecutor;
import org.apache.commons.exec.Executor;
import org.apache.commons.exec.PumpStreamHandler;
import org.apache.commons.io.IOUtils;

import java.io.*;
import java.net.URL;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

class Spider {
    public void catchvideo(String url,String addr) throws IOException {
        //TODO 建立无头浏览器
        WebClient webClient = new WebClient();
        webClient.getOptions().setJavaScriptEnabled(false);
        webClient.getOptions().setCssEnabled(false);
        webClient.getOptions().setThrowExceptionOnFailingStatusCode(true);
        webClient.getOptions().setThrowExceptionOnScriptError(true);
        webClient.addRequestHeader("Referer", "https://www.bilibili.com/index.html");
        webClient.addRequestHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/117.0.0.0 Safari/537.36 Edg/117.0.2045.40");
        //TODO 设置请求参数，建立请求
        WebRequest webRequest = new WebRequest(new URL(url), HttpMethod.GET);

        //TODO 获取响应体
        Page page = webClient.getPage(webRequest);
        WebResponse webResponse = page.getWebResponse();
        String contentAsString = webResponse.getContentAsString();
//        System.out.println(contentAsString);

        //TODO 模式匹配找视频总数
        Pattern pattern = Pattern.compile("<script>window.__INITIAL_STATE__=(.*?);\\(function\\(\\)");
        Matcher matcher = pattern.matcher(contentAsString);
        String s = null;
        if (matcher.find())
            s = matcher.group(1);
        JSONObject jsonObject = JSON.parseObject(s);
        int videonum = jsonObject.getJSONObject("videoData").getIntValue("videos");
//        System.out.println("视频总数" + videonum);

        //TODO 获取目录名
        pattern = Pattern.compile("<meta data-vue-meta=\"true\" property=\"og:title\" content=\"(.*?)_哔哩哔哩_bilibili\">");
        matcher = pattern.matcher(contentAsString);
        String s1 = null;
        if (matcher.find())
            s1 = matcher.group(1);
        else
            System.out.println("没有找到");
        //目录名去除./&*这些字符
        String content = s1.replaceAll("[/&*_，《》\\s+]", "");
//        System.out.println("目录名" + content);

        //TODO 建立目录
        String dir = addr+"\\" + content + "\\";
        File directory = new File(dir);
        if (!directory.exists())
            directory.mkdirs();

        for (int i = 1; i <= videonum; i++) {
            //TODO 设置请求参数，建立请求
            webRequest = new WebRequest(new URL(url + "?p=" + i), HttpMethod.GET);
//            System.out.println(webRequest);
            //TODO 获取响应体
            page = webClient.getPage(webRequest);
            webResponse = page.getWebResponse();
            contentAsString = webResponse.getContentAsString();
            //TODO 获取视频链接
            pattern = Pattern.compile("<script>window.__playinfo__=(.*?)</script>");
            matcher = pattern.matcher(contentAsString);
            String s2 = null;
            if (matcher.find())
                s2 = matcher.group(1);
            else
                System.out.println("没有找到");
            String videolink = JSON.parseObject(s2).getJSONObject("data").getJSONObject("dash").getJSONArray("video").getJSONObject(0).getString("baseUrl");
            String audiolink = JSON.parseObject(s2).getJSONObject("data").getJSONObject("dash").getJSONArray("audio").getJSONObject(0).getString("baseUrl");
//            System.out.println("视频下载链接\n" + videolink);
//            System.out.println("音频下载链接\n" + audiolink);

            //TODO 获取视频名称
            pattern = Pattern.compile("<title data-vue-meta=\"true\">(.*?)_哔哩哔哩_bilibili</title>");
            matcher = pattern.matcher(contentAsString);
            String s3 = null;
            if (matcher.find())
                s3 = matcher.group(1);
            else
                System.out.println("没有找到");
            //目录名去除./&*这些字符
            String videoname = s3.replaceAll("[/&*_，《》\\s+]", "");
            System.out.println(i + "_________________________" + videoname);
            String videofile = dir + "tmp_" + videoname + ".mp4";
            String audiofile = dir + "tmp_" + videoname + ".mp3";

            //TODO 下载视频
            webRequest = new WebRequest(new URL(videolink), HttpMethod.GET);
            page = webClient.getPage(webRequest);
            webResponse = page.getWebResponse();
            InputStream inputStream = webResponse.getContentAsStream();
            OutputStream outputStream = new FileOutputStream(videofile);
            IOUtils.copy(inputStream, outputStream);
            inputStream.close();
            outputStream.close();


            //TODO 下载音频
            webRequest = new WebRequest(new URL(audiolink), HttpMethod.GET);
            page = webClient.getPage(webRequest);
            webResponse = page.getWebResponse();
            inputStream = webResponse.getContentAsStream();

            outputStream = new FileOutputStream(audiofile);
            IOUtils.copy(inputStream, outputStream);
            inputStream.close();
            outputStream.close();

            //TODO 执行合并命令

            // 创建命令行
            CommandLine commandLine = CommandLine.parse("ffmpeg -i " + videofile + " -i " + audiofile + " -c:v copy -c:a aac -strict experimental " + dir + i + "_" + videoname + ".mp4"); // 使用 Windows cmd 命令作为示例
            // 创建执行器
            Executor executor = new DefaultExecutor();
            // 设置输出流处理器（可选）
            PumpStreamHandler streamHandler = new PumpStreamHandler(System.out, System.err); // 将标准输出和错误输出重定向到控制台
            executor.setStreamHandler(streamHandler);
            // 执行命令
//            System.out.println(commandLine);
            executor.execute(commandLine);
//            int exitValue = executor.execute(commandLine); // 执行命令并获取退出值
//            System.out.println("Exit value: " + exitValue); // 打印退出值（通常为0表示成功）

            File file = new File(audiofile);
            file.delete();

            file = new File(videofile);
            file.delete();
        }
    }
}

可视化代码

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.IOException;

public class SwingDemo {
    public static void main(String[] args) {
        JFrame jFrame = new JFrame("Swing frame");
        //设置关闭退出程序
        jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JPanel panel = new JPanel();
        jFrame.setContentPane(panel);
        jFrame.setLocationRelativeTo(null);
        panel.setLayout(new FlowLayout());

        JLabel jLabel = new JLabel("下载地址");
        JTextField jTextField = new JTextField(20);
        jTextField.setToolTipText("下载地址");
        JButton download = new JButton("下载");

        panel.add(jLabel);
        panel.add(jTextField);
        panel.add(download);


        JLabel jLabel1 = new JLabel("文件保存位置");
        JTextField jTextField1 = new JTextField(20);
        jTextField1.setText("D:\\videos\\");
        jTextField1.setToolTipText("文件保存位置");
        JButton fileaddr = new JButton("选择文件夹");

        panel.add(jLabel1);
        panel.add(jTextField1);
        panel.add(fileaddr);

        fileaddr.addActionListener(e -> {
            JFileChooser fileChooser = new JFileChooser();
            fileChooser.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
            int returnValue = fileChooser.showOpenDialog(null);
            if (returnValue == JFileChooser.APPROVE_OPTION) {
                File selectedFile = fileChooser.getSelectedFile();
                jTextField1.setText(selectedFile.getAbsolutePath());
            }
        });

        download.addActionListener(e -> {
            String url = jTextField.getText()+"/";
            String fileAddr = jTextField1.getText();
            System.out.println(url);
            System.out.println(fileAddr);
            try {
                Spider spider = new Spider();
                spider.catchvideo(url,fileAddr);
            } catch (IOException ioException) {
                ioException.printStackTrace();
            }
        });

        //自适应
        jFrame.pack();
        jFrame.setVisible(true);

    }
}