問題描述

我的 XML 看起來像這樣 -

My XML looks like this-

<collected_objects>
        <object flag="complete" id="objId" version="1">
          <variable_value variable_id="varId">ValueGoesHere</variable_value>
          <reference item_ref="2"/>
        </object>
        <object comment="objComment" flag="complete" id="objId" version="1">
          <reference item_ref="1"/>
        </object>
</collected_objects>

我正在使用下面的代碼處理它-

I am processing it using below code-

Document dom = parser.getDocument();
    NodeList collected_objects = dom.getElementsByTagName("object");
    System.out.println("Number of collected objects are " + collected_objects.getLength());

        for (int i = 0; i < collected_objects.getLength(); i++) {

            Node aNode = collected_objects.item(i);
            //get children of "objects"         
            NodeList refNodes = aNode.getChildNodes();

            System.out.println("# of chidren are " + refNodes.getLength());

            //print attributes of "objects"

            NamedNodeMap attributes = aNode.getAttributes();
            for (int a = 0; a < attributes.getLength(); a++) {
             Node theAttribute = attributes.item(a);
             System.out.println(theAttribute.getNodeName() + "=" + theAttribute.getNodeValue());

        }

}

它輸出為-

Number of collected objects are 2
# of chidren are 5
flag=complete
id=objId
version=1
# of chidren are 3
comment=objComment
flag=complete
id=objId
version=1

我的問題是為什么# of chidren are"分別是 5 和 3?我不應該分別期待 2 和 1 嗎?因為第一個對象有variable_value"和reference"，而第二個對象只有reference"

My question is why "# of chidren are" are 5 and 3 respectively? Shouldn't I be expecting 2 and 1 respectively ? because first object has "variable_value" and "reference" and second object has only "reference"

本質上，我的意圖是處理對象"的子級.

Essentially, my intent is to process children of "objects".

推薦答案

那是因為每個子節點之間有2個TEXT_NODE (#text).

That's because you have 2 TEXT_NODE (#text) between each child nodes.

以下包括文本節點及其對應的值.

The following included the text nodes and their corresponding values.

<object flag="complete" id="objId" version="1">
    <TEXT_NODE />
    <variable_value variable_id="varId">ValueGoesHere</variable_value>
    <reference item_ref="2"/>
    <TEXT_NODE />
</object>

這可以通過修改代碼來驗證:

This can be verified by modifying your code:

DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
        Document dom = dBuilder.parse(new ByteArrayInputStream(S.getBytes()));
        NodeList collected_objects = dom.getElementsByTagName("object");
        System.out.println("Number of collected objects are "
                + collected_objects.getLength());

        for (int i = 0; i < collected_objects.getLength(); i++) {

            Node aNode = collected_objects.item(i);
            // get children of "objects"
            NodeList refNodes = aNode.getChildNodes();

            System.out.println("# of chidren are " + refNodes.getLength());

            //
            for (int x = 0; x < refNodes.getLength(); x++) {
                Node n = refNodes.item(x);
                System.out.println(n.getNodeType() + " = " + n.getNodeName() + "/" + n.getNodeValue());
            }

            // print attributes of "objects"

            NamedNodeMap attributes = aNode.getAttributes();
            for (int a = 0; a < attributes.getLength(); a++) {
                Node theAttribute = attributes.item(a);
                System.out.println(theAttribute.getNodeName() + "="
                        + theAttribute.getNodeValue());

            }

        }

輸出:

Number of collected objects are 2
# of chidren are 5
3 = #text/          
1 = variable_value/null
3 = #text/          
1 = reference/null
3 = #text/        
flag=complete
id=objId
version=1
# of chidren are 3
3 = #text/          
1 = reference/null
3 = #text/        
comment=objComment
flag=complete
id=objId
version=1

其中，3 = TEXT_NODE 和 1 = ELEMENT_NODE.

Where, 3 = TEXT_NODE and 1 = ELEMENT_NODE.

這篇關于getChildNodes 給出意外的結果的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！