package com.jeecg.util;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.OutputStream;

import java.net.HttpURLConnection;

import java.net.MalformedURLException;

import java.net.URL;

import java.util.LinkedHashMap;

import java.util.Map;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

import javax.net.ssl.HttpsURLConnection;

import javax.net.ssl.SSLContext;

import javax.net.ssl.SSLSocketFactory;

import javax.net.ssl.TrustManager;

public class WebCrawlerDemo {

    public static void main(String[] args) {

        WebCrawlerDemo webCrawlerDemo = new WebCrawlerDemo();

        webCrawlerDemo.myPrint("https://kyfw.12306.cn/");

    }public void myPrint(String baseUrl) {

        Map<String, Boolean> oldMap = new LinkedHashMap<String, Boolean>();

        // 存储链接-是否被遍历

        // 键值对

        String oldLinkHost = ""; // host

        Pattern p = Pattern.compile("(https?://)?[^/\\s]*");

        // 比如：http://www.zifangsky.cn

        Matcher m = p.matcher(baseUrl);

        if (m.find()) {

            oldLinkHost = m.group();

        }

        oldMap.put(baseUrl, false);

        oldMap = crawlLinks(oldLinkHost, oldMap);

        //oldMap = crawlLinks(baseUrl, oldMap);

        for (Map.Entry<String, Boolean> mapping : oldMap.entrySet()) {

            System.out.println("链接：" + mapping.getKey());

        }

    }

    /**

     * * 抓取一个网站所有可以抓取的网页链接，在思路上使用了广度优先算法 *

     * 对未遍历过的新链接不断发起GET请求，一直到遍历完整个集合都没能发现新的链接 * 则表示不能发现新的链接了，任务结束 * * @param

     * oldLinkHost 域名，如：http://www.zifangsky.cn * @param oldMap 待遍历的链接集合 *

     * * @return 返回所有抓取到的链接集合 *

     */

    private Map<String, Boolean> crawlLinks(String oldLinkHost, Map<String, Boolean> oldMap) {

        Map<String, Boolean> newMap = new LinkedHashMap<String, Boolean>();

        String oldLink = "";

        for (Map.Entry<String, Boolean> mapping : oldMap.entrySet()) {

            System.out.println("link:" + mapping.getKey() + "--------check:" + mapping.getValue());

            // 如果没有被遍历过

            if (!mapping.getValue()) {

                oldLink = mapping.getKey();

                // 发起GET请求

                try {

                    URL url = new URL(oldLink);

                    HttpURLConnection connection = (HttpURLConnection) url.openConnection();

                    connection.setRequestMethod("GET");

                    connection.setConnectTimeout(2000);

                    connection.setReadTimeout(2000);

                    if (connection.getResponseCode() == 200) {

                        InputStream inputStream = connection.getInputStream();

                        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"));

                        String line = "";

                        Pattern pattern = Pattern.compile("<a.*?href=[\"']?((https?://)?/?[^\"']+)[\"']?.*?>(.+)</a>");

                        Matcher matcher = null;

                        while ((line = reader.readLine()) != null) {

                            matcher = pattern.matcher(line);

                            if (matcher.find()) {

                                String newLink = matcher.group(1).trim();

                                // 链接

                                // String title = matcher.group(3).trim(); //标题

                                // 判断获取到的链接是否以http开头

                                if (!newLink.startsWith("http")) {

                                    if (newLink.startsWith("/"))

                                        newLink = oldLinkHost + newLink;

                                    else

                                        newLink = oldLinkHost + "/" + newLink;

                                }

                                // 去除链接末尾的 /

                                if (newLink.endsWith("/"))

                                    newLink = newLink.substring(0, newLink.length() - 1);

                                // 去重，并且丢弃其他网站的链接

                                if (!oldMap.containsKey(newLink) && !newMap.containsKey(newLink)

                                        && newLink.startsWith(oldLinkHost)) {

                                    // System.out.println("temp2: " + newLink);

                                    newMap.put(newLink, false);

                                }

                            }

                        }

                    }

                } catch (MalformedURLException e) {

                    e.printStackTrace();

                } catch (IOException e) {

                    e.printStackTrace();

                }

                try {

                    Thread.sleep(1000);

                } catch (InterruptedException e) {

                    e.printStackTrace();

                }

                oldMap.put(oldLink, true);

            }

        }

        // 有新链接，继续遍历

        if (!newMap.isEmpty()) {

            oldMap.putAll(newMap);

            oldMap.putAll(crawlLinks(oldLinkHost, oldMap));

            // 由于Map的特性，不会导致出现重复的键值对

        }

        return oldMap;

    }

}