import java.io.*;
import java.net.URL;
import java.net.URLConnection;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * @ClassName BKYPageReptile
 * @Description TODO(爬取博客园文章)
 * @Author 我恰芙蓉王
 * @Date 2020年08月11日 9:38
 * @Version 2.0.0
 **/

public class BKYPageReptile {

    //请求地址
    private static final String URL = "https://www.cnblogs.com";

    //保存路径
    private static final String TARGET_PATH = "F://" + "博客园";

    //行匹配正则
    private static final Pattern LINE_PATTERN = Pattern.compile("<a class=\"post-item-title\" href=\"https://www.cnblogs.com/.*?\\.html\" target=\"_blank\">.*?</a>");

    //url正则
    private static final Pattern URL_PATTERN = Pattern.compile("https://www.cnblogs.com/.*?\\.html");

    //标题/文件名正则
    private static final Pattern TITLE_PATTERN = Pattern.compile(">.*?</a>");

    //标题缓存
    private static final List<String> TITLE_LIST = new CopyOnWriteArrayList<>();

    //当前页数
    private static int PAGE = 1;

    //最大拉取页数
    private static final int MAX_PAGE = 200;

    //一共拉取博客篇数
    private static int ALL_COUNT = 0;

    //时间格式
    private static final SimpleDateFormat SDF = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    public static void main(String[] args) {
        //创建根目录
        File rootDir = new File(TARGET_PATH);
        if (!rootDir.exists()) {
            rootDir.mkdir();
        }

        //创建日志文件夹
        String logPath = TARGET_PATH + "//拉取日志";
        File logDir = new File(logPath);
        if (!logDir.exists()) {
            logDir.mkdir();
        }

        //创建日志文件
        File logFile = new File(logPath + "//log.txt");
        if (!logFile.exists()) {
            try {
                logFile.createNewFile();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        //循环拉取
        while (PAGE <= MAX_PAGE) {
            //日志内容
            String logContent = "正在拉取第" + PAGE + "页\n";
            System.err.println("\n" + logContent);
            String param = "PageIndex=" + PAGE;

            try {
                //获取指定页页返回内容
                String response = sendPost(URL, param);

                Matcher matcher = LINE_PATTERN.matcher(response);

                //需要写入的文件集合
                ArrayList<FileTemplate> urlList = new ArrayList<>(20);

                /**
                 * 解析返回内容封装成FileTemplate
                 */
                while (matcher.find()) {
                    //匹配行
                    String matchLine = matcher.group();

                    Matcher matcher1 = TITLE_PATTERN.matcher(matchLine);
                    String title = null;
                    while (matcher1.find()) {
                        //匹配的标题    >标题</a>
                        title = matcher1.group();
                    }
                    //截取拿到真实标题
                    title = title.substring(1, title.length() - 4);
                    //特殊字符处理
                    title = title.replace("<", "《")
                            .replace(">", "》")
                            .replace("\\", "-")
                            .replace("/", "-")
                            .replace(":", "：")
                            .replace("*", "")
                            .replace("?", "？")
                            .replace("|", "")
                            + ".html";
                    System.err.println("title = " + title);

                    //如果已经拉取了此标题的html文件   则跳过此篇
                    if (TITLE_LIST.contains(title)) {
                        continue;
                    }

                    Matcher matcher2 = URL_PATTERN.matcher(matchLine);
                    String url = null;
                    while (matcher2.find()) {
                        //匹配博客的请求url
                        url = matcher2.group();
                    }
                    //封装成文件模板对象
                    urlList.add(new FileTemplate(url, title, false));
                }


                /**
                 * 写入磁盘
                 */
                urlList.parallelStream().forEach(v -> {
                    FileOutputStream fos = null;
                    PrintWriter pw = null;
                    try {
                        String result = sendGet(v.getGetUrl(), "");
                        File file = new File(TARGET_PATH + File.separator + v.getTitle());
                        file.createNewFile();

                        fos = new FileOutputStream(file);
                        pw = new PrintWriter(fos);
                        pw.write(result.toCharArray());
                        pw.flush();
                        v.setFlag(true);

                        TITLE_LIST.add(v.getTitle());
                    } catch (Exception e) {
                        System.out.println(v.toString());
                        e.printStackTrace();
                    } finally {
                        try {
                            if (fos != null) {
                                fos.close();
                            }
                            if (pw != null) {
                                pw.close();
                            }
                        } catch (IOException e) {
                            e.printStackTrace();
                        }

                    }
                });

                /**
                 * 记录日志
                 */
                //本次写入成功博客数
                long count = urlList.stream().filter(v -> v.getFlag()).count();

                String date = SDF.format(new Date());

                //累加次数
                ALL_COUNT += count;

                logContent += "本次拉取完成,共  " + count + "  篇新博客\r\n";
                logContent += "一共拉取了  " + ALL_COUNT + "  篇\r\n";
                logContent += "时间 : " + date + "\n\n";
                BufferedWriter out = null;
                try {
                    out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(logFile, true)));
                    out.write(logContent + "\r\n");
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    try {
                        out.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }

                PAGE++;
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 文件模板类
     */
    private static class FileTemplate {
        /**
         * 请求地址
         */
        private String getUrl;

        /**
         * 标题
         */
        private String title;

        /**
         * 已经爬取标识
         */
        private boolean flag;

        public FileTemplate(String getUrl, String title, boolean flag) {
            this.getUrl = getUrl;
            this.title = title;
            this.flag = flag;
        }

        public String getGetUrl() {
            return getUrl;
        }

        public void setGetUrl(String getUrl) {
            this.getUrl = getUrl;
        }

        public String getTitle() {
            return title;
        }

        public void setTitle(String title) {
            this.title = title;
        }

        @Override
        public String toString() {
            final StringBuilder sb = new StringBuilder("FileTemplate{");
            sb.append("getUrl='").append(getUrl).append('\'');
            sb.append(", title='").append(title).append('\'');
            sb.append('}');
            return sb.toString();
        }

        public boolean getFlag() {
            return flag;
        }

        public void setFlag(boolean flag) {
            this.flag = flag;
        }
    }

    /**
     * 功能描述: 向指定URL发送GET请求
     *
     * @param url   发送请求的URL
     * @param param 请求参数，请求参数应该是 name1=value1&name2=value2 的形式
     * @创建人: 我恰芙蓉王
     * @创建时间: 2020年08月11日 16:42:17
     * @return: java.lang.String  响应结果
     **/
    public static String sendGet(String url, String param) {
        StringBuilder sb = new StringBuilder();
        BufferedReader in = null;
        try {
            String urlNameString = url + "?" + param;
            URL realUrl = new URL(urlNameString);
            // 打开和URL之间的连接
            URLConnection connection = realUrl.openConnection();
            // 设置通用的请求属性
            connection.setRequestProperty("accept", "*/*");
            connection.setRequestProperty("connection", "Keep-Alive");
            connection.setRequestProperty("user-agent",
                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            // 建立实际的连接
            connection.connect();
            // 获取所有响应头字段
            Map<String, List<String>> map = connection.getHeaderFields();
            // 定义 BufferedReader输入流来读取URL的响应
            in = new BufferedReader(new InputStreamReader(
                    connection.getInputStream()));
            String line;
            while ((line = in.readLine()) != null) {
                sb.append(line);
            }
        } catch (Exception e) {
            System.out.println("发送GET请求出现异常！" + e);
            e.printStackTrace();
        }
        // 使用finally块来关闭输入流
        finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
        return sb.toString();
    }

    /**
     * 功能描述: 向指定URL发送POST请求
     *
     * @param url   发送请求的URL
     * @param param 请求参数，请求参数应该是 name1=value1&name2=value2 的形式
     * @创建人: 我恰芙蓉王
     * @创建时间: 2020年08月11日 16:42:17
     * @return: java.lang.String  响应结果
     **/
    public static String sendPost(String url, String param) {
        PrintWriter out = null;
        BufferedReader in = null;
        StringBuilder sb = new StringBuilder();
        try {
            URL realUrl = new URL(url);
            // 打开和URL之间的连接
            URLConnection conn = realUrl.openConnection();
            // 设置通用的请求属性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent",
                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            // 发送POST请求必须设置如下两行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            // 获取URLConnection对象对应的输出流
            out = new PrintWriter(conn.getOutputStream());
            // 发送请求参数
            out.print(param);
            // flush输出流的缓冲
            out.flush();
            // 定义BufferedReader输入流来读取URL的响应
            in = new BufferedReader(
                    new InputStreamReader(conn.getInputStream()));
            String line;
            while ((line = in.readLine()) != null) {
                sb.append(line);
            }
        } catch (Exception e) {
            System.out.println("发送 POST 请求出现异常！" + e);
            e.printStackTrace();
        }
        //使用finally块来关闭输出流、输入流
        finally {
            try {
                if (out != null) {
                    out.close();
                }
                if (in != null) {
                    in.close();
                }
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
        return sb.toString();
    }
}