用包含多个页面的多个字母标签抓取网站

Question

我正在抓取一个网站，该网站在A-Z选项卡中按字母顺序列出数据，每个字母选项卡还包含多个页面。我如何从中提取所有URL？

公共静态void main（字符串[]args）引发异常{

String keyword = "a";
String url = "http://www.medindia.net/drug-price/brand-index.asp?alpha=" + keyword; 

Document doc = Jsoup.connect(url).get();
//Elements pages = doc.select("div.pagination a"); 
Element table = doc.select("table").get(1);

for (Element row : table.select("tr")) {
    for (Element tds : row.select("td")) {
        Elements links = tds.select("a[href]");
        for (Element link : links) {
            System.out.println("link : " + link.attr("href"));
            System.out.println("text : " + link.text());
           }
        }
    }

Answer 1

所以我能够找出如何从每个字母表选项卡和每个字母表选项卡内的每个页面中刮取数据。下面是代码。然而，在抓取了几百个链接后，我得到了一个读取超时错误。有没有有效的方法？我可以对此应用多线程吗？

public static void main(String[] args) throws Exception {

        final int OK = 200;
        String currentURL;
        int page = 1;
        int status = OK;
        Connection.Response response = null;
        Document doc = null;
        String[] keywords = {"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};
        //String keyword = "a";
        for (String keyword : keywords){
            final String url = "https://www.medindia.net/drug-price/brand-index.asp?alpha="+keyword; 
            while (status == OK) {
                currentURL = url +"&page="+ String.valueOf(page); 
                response = Jsoup.connect(currentURL)
                        .userAgent("Mozilla/5.0")
                        .execute();
                status = response.statusCode();


                if (status == OK) {
                    doc = response.parse();

                    Element table = doc.select("table").get(1);

                    for (Element rows : table.select("tr")) {
                        for (Element tds : rows.select("td")) {
                            Elements links = tds.select("a[href]");
                            for (Element link : links) {
                                System.out.println("link : " + link.attr("href"));
                                System.out.println("text : " + link.text());
                            }
                        }
                    }

                }
                page++;
            }

        }
    }