在 JAVA 中使用 SAX 解析器从 XML 文件中提取文本节点

2022-01-10 00:00:00 xml parsing xml-parsing java sax

所以我目前正在使用 SAX 尝试从我正在处理的许多 xml 文档中提取一些信息.到目前为止，提取属性值真的很容易.但是，我不知道如何从文本节点中提取实际值.

So I am currently using SAX to try and extract some information from a a number of xml documents I am working from. Thus far, it is really easy to extract the attribute values. However, I have no clue how to go about extracting actual values from a text node.

例如，在给定的 XML 文档中:

For example, in the given XML document:

<w:rStyle w:val="Highlight" /> 
  </w:rPr>
  </w:pPr>
- <w:r>
  <w:t>Text to Extract</w:t> 
  </w:r>
  </w:p>
- <w:p w:rsidR="00B41602" w:rsidRDefault="00B41602" w:rsidP="007C3A42">
- <w:pPr>
  <w:pStyle w:val="Copy" />

通过从 val 获取值，我可以毫无问题地提取突出显示".但我不知道如何进入该文本节点并退出要提取的文本".

I can extract "Highlight" no problem by getting the value from val. But I have no idea how to get into that text node and get out "Text to Extract".

这是我迄今为止提取属性值的 Java 代码...

private static final class SaxHandler extends DefaultHandler 
    {
        // invoked when document-parsing is started:
        public void startDocument() throws SAXException 
        {
            System.out.println("Document processing starting:");
        }

        // notifies about finish of parsing:
        public void endDocument() throws SAXException 
        {
            System.out.println("Document processing finished. 
");
        }

        // we enter to element 'qName':
        public void startElement(String uri, String localName, 
                String qName, Attributes attrs) throws SAXException 
        {
            if(qName.equalsIgnoreCase("Relationships"))
            {
                // do nothing
            }
            else if(qName.equalsIgnoreCase("Relationship"))
            {
                // goes into the element and if the attribute is equal to "Target"...
                String val = attrs.getValue("Target");
                // ...and the value is not null
                if(val != null)
                {
                    // ...and if the value contains "image" in it...
                    if (val.contains("image"))
                    {
                        // ...then get the id value
                        String id = attrs.getValue("Id");
                        // ...and use the substring method to isolate and print out only the image & number
                        int begIndex = val.lastIndexOf("/");
                        int endIndex = val.lastIndexOf(".");
                        System.out.println("Id: " + id + " & Target: " + val.substring(begIndex+1, endIndex));
                    }
                }
            }
            else 
            {
                throw new IllegalArgumentException("Element '" + 
                        qName + "' is not allowed here");
            }
        }

        // we leave element 'qName' without any actions:
        public void endElement(String uri, String localName, String qName) throws SAXException 
        {
            // do nothing;
        }
     }

但我不知道从哪里开始进入该文本节点并提取其中的值.有人有什么想法吗?

But I have no clue where to start to get into that text node and pull out the values inside. Anyone have some ideas?

推荐答案

下面是一些伪代码:

private boolean insideElementContainingTextNode;
private StringBuilder textBuilder;

public void startElement(String uri, String localName, String qName, Attributes attrs) {
    if ("w:t".equals(qName)) { // or is it localName?
        insideElementContainingTextNode = true;
        textBuilder = new StringBuilder();
    }
}

public void characters(char[] ch, int start, int length) {
    if (insideElementContainingTextNode) {
        textBuilder.append(ch, start, length);
    }
}

public void endElement(String uri, String localName, String qName) {
    if ("w:t".equals(qName)) { // or is it localName?
        insideElementContainingTextNode = false;
        String theCompleteText = this.textBuilder.toString();
        this.textBuilder = null;
    }
}

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