Question

当他们点击退出按钮时，尝试这样做，他们的名字和金额存储在XML文件中。我还要阅读那里的当前XML文件

在向XML文件添加新节点时遇到问题。

private void exitButtonActionPerformed(java.awt.event.ActionEvent evt) {                                           
    try {

        DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
        Document document = documentBuilder.parse("scores.xml");

        Element rootElement = document.createElement("scores");
        document.appendChild(rootElement);

        Element player = document.createElement("player");
        Element playerName = document.createElement("name");
        Element moneyAmount = document.createElement("money");
        playerName.appendChild(document.createTextNode(name));
        playerName.appendChild(document.createTextNode(String.valueOf(money)));
        player.appendChild(playerName);

        DOMSource source = new DOMSource(document);

        TransformerFactory transformerFactory = TransformerFactory.newInstance();
        Transformer transformer = transformerFactory.newTransformer();
        StreamResult result = new StreamResult("scores.xml");
        transformer.transform(source, result);

        System.exit(0);
        }
    catch (ParserConfigurationException ex) {
        ex.printStackTrace();
        } catch (SAXException ex) {
        ex.printStackTrace();
        } catch (IOException ex) {
        ex.printStackTrace();
        }
    }

当前XML：

<scores>
    <player>
        <name>Chief Sosa</name>
        <money>1000</money>
    </player> 
</scores>

我想添加其他玩家期望的：

<scores>
    <player>
        <name>Chief Sosa</name>
        <money>1000</money>
    </player> 

    <player>
        <name>Kobe</name>
        <money>11000000</money>
    </player> 
</scores>

Answer 1

为您提供2种可能的解决方案：

1。通过setAttribute函数定义您的节点ID。之后，xml文件将如下所示

<scores id ="scoreId">

</scores>

当您想要添加其他玩家时。使用以下命令查找具有ID的节点：

Node n = document.getElementById("scoreId");

创建一个播放器最后是这个节点中的apendChild。

2。另一种解决方案是使用document.getElementsByTagName("scores");

在此结果中循环并附加您的节点。

希望这个帮助

Answer 2

这假设一个预先存在的分数文件......

首先获取文档的“根”节点...

Element rootElement = document.getDocumentElement();

然后，而不是尝试从变量name和money追加“文本”......

// This is creating a mess
Element player = document.createElement("player");
Element playerName = document.createElement("name");
Element moneyAmount = document.createElement("money");
playerName.appendChild(document.createTextNode(name));
playerName.appendChild(document.createTextNode(String.valueOf(money)));
player.appendChild(playerName);

您想要设置适当的节点文本内容

Element player = document.createElement("player");
Element playerName = document.createElement("name");
playerName.setTextContent(name);
Element moneyAmount = document.createElement("money");
moneyAmount.setTextContent(NumberFormat.getNumberInstance().format(money));

接下来，您要将名称和moneny节点附加到player元素...

player.appendChild(playerName);
player.appendChild(moneyAmount);

然后将player节点附加到“root”

rootElement.appendChild(player);

<强>更新

您可以使用以下内容......

Document document = null;
File scores = new File("scores.xml");
if (scores.exists()) {

    document = documentBuilder.parse("scores.xml");

} else {

    document = documentBuilder.newDocument();
    document.appendChild(document.createElement("scores"));

}

要加载或创建新文档（如果它不存在），请按照前面的示例使用附加代码......

更新了示例...

使用...

try {

    DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
    DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();

    Document document = null;
    File scores = new File("scores.xml");
    if (scores.exists()) {

        document = documentBuilder.parse("scores.xml");

    } else {

        document = documentBuilder.newDocument();
        document.appendChild(document.createElement("scores"));

    }

    Element rootElement = document.getDocumentElement();

    String name = "Kobe";
    double money = 11000000;

    Element player = document.createElement("player");
    Element playerName = document.createElement("name");
    playerName.setTextContent(name);
    Element moneyAmount = document.createElement("money");
    moneyAmount.setTextContent(NumberFormat.getNumberInstance().format(money));

    player.appendChild(playerName);
    player.appendChild(moneyAmount);

    rootElement.appendChild(player);

    DOMSource source = new DOMSource(document);

    Transformer tf = TransformerFactory.newInstance().newTransformer();
    tf.setOutputProperty(OutputKeys.INDENT, "yes");
    tf.setOutputProperty(OutputKeys.METHOD, "xml");
    tf.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "4");

    StreamResult result = new StreamResult(scores);
    tf.transform(source, result);

} catch (ParserConfigurationException | SAXException | IOException | TransformerException ex) {
    ex.printStackTrace();
}

从...开始

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<scores>
    <player>
        <name>Chief Sosa</name>
        <money>1,000</money>
    </player>
</scores>

我能够生成

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<scores>
    <player>
        <name>Chief Sosa</name>
        <money>1,000</money>
    </player>
    <player>
        <name>Kobe</name>
        <money>11,000,000</money>
    </player>
</scores>

如何通过Java将节点附加到我的XML

2 个答案: