Java數據爬取——爬取攜程酒店數據（一）

最近工作要收集點酒店數據，就到攜程上看了看，記錄爬取過程去下

1.根據城市名稱來分類酒店數據，所以先找了所有城市的名稱
在這個網頁上有http://hotels.ctrip.com/domestic-city-hotel.html

從網站地圖上可以很容易發現這個頁面

2.然後查看源碼

發現所有需要的數據都在

<dl class = "pinyin_filter_detail layoutfix"></dl>

3.我們獲取一下dl 這個元素和其中的所有子元素

我們用jsoup的jar包來解析獲取的html，官網https://jsoup.org/，有API和jar包

String result = HttpUtil.getInstance().httpGet(null, "http://hotels.ctrip.com/domestic-city-hotel.html");
Document root_document = Jsoup.parse(result);
Elements pinyin_filter_elements = root_document.getElementsByClass("pinyin_filter_detail layoutfix");

//包含所有城市的Element
Element pinyin_filter = pinyin_filter_elements.first();

4.我準備把獲取的城市數據存儲到mysql中，所以下面連接了本地mysql數據庫

// 連接數據庫
Connection conn = SqlDBUtils.getConnection();
StringBuilder create_table_sql = new StringBuilder();
create_table_sql.append("create table if not exists ctrip_hotel_city (id integer primary key auto_increment, city_id integer not null, city_name varchar(255) not null, head_pinyin varchar(80) not null, pinyin varchar(255) not null)");
PreparedStatement preparedStatement;
try {
    //每次執行刪除一下表，防止數據插入重複
    preparedStatement = conn.prepareStatement("DROP TABLE IF EXISTS ctrip_hotel_city");
    preparedStatement.execute();
    // 創建ctrip_hotel_city表，存儲城市數據
    preparedStatement = conn.prepareStatement(create_table_sql.toString());
    preparedStatement.execute();
} catch (SQLException e) {
    e.printStackTrace();
}

5.獲取dl下所有的dt和dd，並從中提取數據庫表中所需要的字段，實現存儲

//拼音首字符Elements
Elements pinyins = pinyin_filter.getElementsByTag("dt");
//所有dd的Elements
Elements hotelsLinks = pinyin_filter.getElementsByTag("dd");

6.數據提取

for (int i = 0; i < pinyins.size(); i++) {
    Element head_pinyin = pinyins.get(i);
    Element head_hotelsLink = hotelsLinks.get(i);
    Elements links = head_hotelsLink.children();
    for (Element link : links) {
        String cityId = StringUtil.getNumbers(link.attr("href"));
        String cityName = link.html();
        String head_pinyin_str = head_pinyin.html();
        String pinyin_cityId = link.attr("href").replace("/hotel/", "");
        String pinyin = pinyin_cityId.replace(StringUtil.getNumbers(link.attr("href")), "");
        StringBuffer insert_sql = new StringBuffer();
        insert_sql.append("insert into ctrip_hotel_city (city_id, city_name, head_pinyin, pinyin) values (");
        insert_sql.append(cityId);
        insert_sql.append(", '" + cityName + "'");
        insert_sql.append(", '" + head_pinyin_str + "'");
        //此處注意漢語拼音中會有'，直接插入數據庫會報錯，要把一個'替換爲兩個''
        insert_sql.append(", '" + pinyin.replace("'", "''") + "')");
        try {
            preparedStatement = conn.prepareStatement(insert_sql.toString());
            preparedStatement.execute();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}