使用 jdom 从 xml 获取 body 标记的子级时出错

发布于 2024-10-21 04:45:40 字数 933 浏览 5 评论 0原文

我需要遍历 JDOM 树并从正文部分提取所有数据，以便在另一个 xml 文档创建中使用它。我对编程很陌生。我已附上我的概念和控制台中显示的错误。我想澄清一下这个概念是对是错。任何人都可以帮助我了解这一点并给予指导吗？

将不胜感激任何指示..

//root- Existing document's root.
//body- New documents body.
private static Element listChildren(Element root, int depth) {
    System.out.println(root.getName());
    List children = root.getChild("body").getChildren();
    Iterator iterator = children.iterator();
    while (iterator.hasNext()) {
         Element child = (Element) iterator.next();
         System.out.println(child.toString());
         body.addContent(child);
         listChildren(child, depth+1);
         return child;
    }

    return null;
}

显示错误：

Exception in thread "main" java.lang.NullPointerException
    at createXhtml1.listChildren(createXhtml1.java:85)
    at createXhtml1.newXhtml(createXhtml1.java:62)
    at createXhtml1.main(createXhtml1.java:112)

原文

I need to walk through a JDOM tree and extract all data from body section to use it in another xml document creation. I'm very new to programming. I have attached my concept and error shown in console. I want to clarify whether this concept is right or wrong. Could any body help me to know about this and give a direction?

Would appreciate any pointers..

//root- Existing document's root.
//body- New documents body.
private static Element listChildren(Element root, int depth) {
    System.out.println(root.getName());
    List children = root.getChild("body").getChildren();
    Iterator iterator = children.iterator();
    while (iterator.hasNext()) {
         Element child = (Element) iterator.next();
         System.out.println(child.toString());
         body.addContent(child);
         listChildren(child, depth+1);
         return child;
    }

    return null;
}

Error shown:

Exception in thread "main" java.lang.NullPointerException
    at createXhtml1.listChildren(createXhtml1.java:85)
    at createXhtml1.newXhtml(createXhtml1.java:62)
    at createXhtml1.main(createXhtml1.java:112)

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

铁轨上的流浪者 2024-10-28 04:45:40

因此，根据评论，您的问题出在 root.getChild("body") 上。此方法返回 null（根元素中没有名为 body 的子元素）。您应该检查 null 并从方法中返回 null。

....
Element element = root.getChild("body")    
if (element == null)
    return null;
List children = element.getChildren();
...

编辑
根据评论，您可以打印（或任何您想做的事情）所有元素。

public class Test {
    public static void main(String[] args) throws Exception {
        String xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?><html> <body> <h1 align=\"center\">Profile</h1><hr /> <div class=\"centered\"> <table><tr><td><strong>Name: </strong></td> <td>A</td> </tr> <tr> <td><strong>Age: </strong></td> <td>23</td> <td>programmer</td></tr><tr><td><strong>Email: </strong></td><td>[email protected]</td></tr></table></div><hr /></body></html>";
        SAXBuilder builder = new SAXBuilder();
        Document doc = builder.build(new StringReader(xml));
        listChildren(doc.getRootElement(), 0);
    }

    private static void listChildren(Element root, int depth) {
        System.out.println(root.getName());
        List<Element> children = root.getChildren();
        if (children == null || children.isEmpty())
                return;
        for (Element child : children) {
                 System.out.println(child.toString());
                 listChildren(child, depth+1);
        }

        return;
    }
}

So based on comments your problem is with root.getChild("body"). This method returns null (there's no child named body in root element). You should check for null and return null from method.

....
Element element = root.getChild("body")    
if (element == null)
    return null;
List children = element.getChildren();
...

EDIT
According to comment, you can print (or whatever you want to do) all elements.

public class Test {
    public static void main(String[] args) throws Exception {
        String xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?><html> <body> <h1 align=\"center\">Profile</h1><hr /> <div class=\"centered\"> <table><tr><td><strong>Name: </strong></td> <td>A</td> </tr> <tr> <td><strong>Age: </strong></td> <td>23</td> <td>programmer</td></tr><tr><td><strong>Email: </strong></td><td>[email protected]</td></tr></table></div><hr /></body></html>";
        SAXBuilder builder = new SAXBuilder();
        Document doc = builder.build(new StringReader(xml));
        listChildren(doc.getRootElement(), 0);
    }

    private static void listChildren(Element root, int depth) {
        System.out.println(root.getName());
        List<Element> children = root.getChildren();
        if (children == null || children.isEmpty())
                return;
        for (Element child : children) {
                 System.out.println(child.toString());
                 listChildren(child, depth+1);
        }

        return;
    }
}

回复收藏 0 原文

~没有更多了~