解析 Facebook 的 XML 查询响应问题

Question

嘿伙计们！ :) 我正在开发一项服务，可以从 Facebook API 捕获点赞数、分享数等。 但有一个问题，因为我从 fqlResponse.getChild() 得到一个空指针异常。

我认为自动检测xmls doctype有问题，所以我手动定义了doctype，但问题仍然存在。也许 facebooks xml 文档类型不正确？ 下面是捕获方法：

public void refreshLikesSharesClicksAndTotal() throws JDOMException, IOException {
    URL fqlURL = new URL("https://api.facebook.com/method/fql.query?query=select  like_count,    total_count, share_count, click_count from link_stat where url=\"" + this.url.toString() + "\"");
    Document inputXML = new SAXBuilder().build(fqlURL);
    DocType docType = new DocType("xml", "http://www.w3.org/2001/XMLSchema-instance");
    inputXML.setDocType(docType);
    Element fqlResponse = inputXML.getRootElement().getChild("link_stat");
    Element likes = fqlResponse.getChild("like_count");
    logger.info("Likes: " + likes.getText());
    Element shares = fqlResponse.getChild("share_count");
    Element clicks = fqlResponse.getChild("click_count");
    Element total = fqlResponse.getChild("total_count");

    this.likes = Integer.parseInt(likes.getText());
    this.shares = Integer.parseInt(shares.getText());
    this.clicks = Integer.parseInt(clicks.getText());
    this.total = Integer.parseInt(total.getText());

}

XML 示例： https://api.facebook.com/method/fql.query?query=select%20%20like_count,%20total_count,%20share_count,%20click_count%20from%20link_stat%20where%20url=%22http： //heise.de%22

德语问题描述： http://www.java-forum .org/xml-co/118648-problem-beim-parsen-facebook-xml.html

感谢您的帮助！ 怀特内克斯

Answer 1

您可以执行以下操作：-

    URL url = new URL("https://api.facebook.com/method/fql.query?query=select%20like_count,%20total_count,%20share_count,%20click_count%20from%20link_stat%20where%20url=%22http://heise.de%22");

    DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
    domFactory.setNamespaceAware(true);
    Document doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(url.openStream());
    XPath xPath = XPathFactory.newInstance().newXPath();

    int likeCount = Integer.parseInt(xPath.evaluate("//like_count/text()", doc));
    int totalCount = Integer.parseInt(xPath.evaluate("//total_count/text()", doc));
    int shareCount = Integer.parseInt(xPath.evaluate("//share_count/text()", doc));
    int clickCount = Integer.parseInt(xPath.evaluate("//click_count/text()", doc));

确保使用 %20 和 %22 适当地对 URL 中的空格和双引号进行编码。我已经测试了这段代码，它对我有用。

Answer 2

它对我有用：

    public void refreshLikesSharesClicksAndTotal() throws JDOMException, IOException {
        URL fqlURL = new URL("https://api.facebook.com/method/fql.query?query=select%20like_count,%20total_count,%20share_count,%20click_count%20from%20link_stat%20where%20url=%22http://heise.de%22");
        URLConnection openConnection = fqlURL.openConnection();     
        String contentType = openConnection.getContentType();
        Document inputXML = new SAXBuilder().build(fqlURL);
        DocType docType = new DocType("xml", "http://www.w3.org/2001/XMLSchema-instance");
        inputXML.setDocType(docType);
        Element root = inputXML.getRootElement();

        Element fqlResponse = root.getChild("link_stat", root.getNamespace());
        Element likes = fqlResponse.getChild("like_count", root.getNamespace());
        Element shares = fqlResponse.getChild("share_count", root.getNamespace());
        Element clicks = fqlResponse.getChild("click_count", root.getNamespace());
        Element total = fqlResponse.getChild("total_count", root.getNamespace());

        int alikes = Integer.parseInt(likes.getText());
        int ashares = Integer.parseInt(shares.getText());
        int aclicks = Integer.parseInt(clicks.getText());
        int atotal = Integer.parseInt(total.getText());

    }

当您调用 getChild 和 %20 & 时，我刚刚插入了“root.getNamespace()”查询中的 %22