问题描述

我正在寻找一个简单的 Java 片段来从(任何)XML 结构中删除空标签

I'm looking for a simple Java snippet to remove empty tags from a (any) XML structure

<xml>
    <field1>bla</field1>
    <field2></field2>
    <field3/>
    <structure1>
       <field4>bla</field4>
       <field5></field5>
    </structure1>
</xml>

应该变成;

<xml>
    <field1>bla</field1>
    <structure1>
       <field4>bla</field4>
    </structure1>
</xml>

推荐答案

我想知道使用 XOM 库并试一试.

I was wondering whether it would be easy to do this with the XOM library and gave it a try.

结果很简单:

import nu.xom.*;

import java.io.File;
import java.io.IOException;

public class RemoveEmptyTags {

    public static void main(String[] args) throws IOException, ParsingException {
        Document document = new Builder().build(new File("original.xml"));
        handleNode(document.getRootElement());
        System.out.println(document.toXML()); // empty elements now removed
    }

    private static void handleNode(Node node) {
        if (node.getChildCount() == 0 && "".equals(node.getValue())) {
            node.getParent().removeChild(node);
            return;
        }
        // recurse the children
        for (int i = 0; i < node.getChildCount(); i++) { 
            handleNode(node.getChild(i));
        }
    }
}

这可能无法正确处理所有极端情况，例如完全空的文档.以及如何处理原本为空但具有属性的元素?

This probably won't handle all corner cases properly, like a completely empty document. And what to do about elements that are otherwise empty but have attributes?

如果要保存带有属性的 XML 标签，我们可以在方法 'handleNode' 中添加以下检查:

If you want to save XML tags with attributes, we can add in the method 'handleNode' the following check:

... && ((Element) node).getAttributeCount() == 0) )

另外，如果xml有两个或多个空标签，一个接一个；这种递归方法不会删除所有空标签！

Also, if the xml has two or more empty tags, one after another; this recursive method doesn't remove all empty tags!

(这个答案是我对 XOM 作为潜在的评估的一部分 替换为 dom4j.)

(This answer is part of my evaluation of XOM as a potential replacement to dom4j.)

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