從URL讀取XML文件

Question

我嘗試從https://www.nbp.pl/kursy/xml/c001z020102.xml中讀取xml文件。

我添加了數字sout來觀察進度。

public void wypisanie() throws Exception
        {
            URL url = new URL("https://www.nbp.pl/kursy/xml/c001z020102.xml");
            System.out.println("1");
            URLConnection urlConnection = url.openConnection();
            System.out.println("2");
            InputStream in = new BufferedInputStream(urlConnection.getInputStream());
            System.out.println("3");
            DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
            System.out.println("4");
            DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
            System.out.println("5");
            Document doc1 = dBuilder.parse( in );
            System.out.println("6");
            Element element1 = doc1.getDocumentElement();
            System.out.println("7");
            NodeList nodes1 = element1.getChildNodes();
            System.out.println("8");
            for (int i = 0; i < nodes1.getLength(); i++) {
                System.out.println("" + nodes1.item(i).getTextContent());
            }
        }

這是結果：

1
2
https://www.nbp.pl/kursy/xml/c001z020102

我的目標是通過此網址獲得美元匯率。 有人有其他想法我應該怎么做？

編輯：我嘗試使用這樣的其他URL： https ： //www.w3schools.com/xml/plant_catalog.xml和程序工作。 那么“舊”網址有什么問題？ https://www.nbp.pl/kursy/xml/c001z020102.xml

“舊”網址的結果

1
2
3
4
5
C:\Users\user\IdeaProjects\NBP\untitled\abch.dtd (The system cannot find the file specified)

Answer 1

您的計算機上沒有DTD文件。

嘗試這個：

    public void wypisanie() throws Exception {
        URL url = new URL("https://www.nbp.pl/kursy/xml/c001z020102.xml");
        System.out.println("1");
        URLConnection urlConnection = url.openConnection();
        System.out.println("2");
        InputStream in = new BufferedInputStream(urlConnection.getInputStream());
        System.out.println("3");

        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

        dbf.setValidating(false);
        dbf.setNamespaceAware(true);
        dbf.setFeature("http://xml.org/sax/features/namespaces", false);
        dbf.setFeature("http://xml.org/sax/features/validation", false);
        dbf.setFeature("http://apache.org/xml/features/nonvalidating/load-dtd-grammar", false);
        dbf.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);

        System.out.println("4");
        DocumentBuilder dBuilder = dbf.newDocumentBuilder();
        System.out.println("5");
        Document doc1 = dBuilder.parse(in);
        System.out.println("6");
        Element element1 = doc1.getDocumentElement();
        System.out.println("7");
        NodeList nodes1 = element1.getChildNodes();
        System.out.println("8");
        for (int i = 0; i < nodes1.getLength(); i++) {
            if ("pozycja".equals(nodes1.item(i).getNodeName())) {
                System.out.println("" + nodes1.item(i).getTextContent());
            }
        }
    }