如何将节点附加到java中的现有XML文件 [英] How do I append a node to an existing XML file in java

问题描述

public static void addALLToXML(Collection<Server> svr) throws IOException,
      ParserConfigurationException, TransformerException
{
    DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory
        .newInstance();
    DocumentBuilder documentBuilder = documentBuilderFactory
        .newDocumentBuilder();
    Document document = documentBuilder.newDocument();

    // Root Element
    Element rootElement = document.createElement("Servers");
    document.appendChild(rootElement);

    for (Server i : svr)
    {
        // server elements
        Element server = document.createElement("server");
        rootElement.appendChild(server);

        Element name = document.createElement("name");
        name.appendChild(document.createTextNode(i.getName()));
        server.appendChild(name);

        Element port = document.createElement("port");
        port.appendChild(document.createTextNode(Integer.toString(i.getPort())));
        server.appendChild(port);
    }

    TransformerFactory transformerFactory = TransformerFactory.newInstance();
    Transformer transformer = transformerFactory.newTransformer();
    DOMSource source = new DOMSource(document);

    StreamResult result = new StreamResult("/home/user/server.xml");
    transformer.transform(source, result);
}

这是我需要帮助的功能：

This is the function I need help with:

public static void addNodeToXML(String nameIn, String portIn)
      throws ParserConfigurationException, SAXException, IOException
{
    DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory
            .newInstance();
    DocumentBuilder documentBuilder = documentBuilderFactory
            .newDocumentBuilder();

    /* parse existing file to DOM */
    Document document = documentBuilder
            .parse(new File("/home/user/server.xml"));

    // Root Element
    Element rootElement = document.createElement("Servers");
    document.appendChild(rootElement);

    // server elements
    Element server = document.createElement("server");
    rootElement.appendChild(server);

    Element name = document.createElement("name");
    name.appendChild(document.createTextNode(nameIn));
    server.appendChild(name);

    Element port = document.createElement("port");
    port.appendChild(document.createTextNode(portIn));
    server.appendChild(port);
}

原文：

<Servers>
 <server>
  <name>something</name>
  <port>port</port>
 </server>
 </Servers>

通缉：

<Servers> 
  <server>
   <name>something</name>
   <port>port</port>
  </server>
  <server>
   <name>something</name>
   <port>port</port>
  </server>
<Servers>

推荐答案

以下完整示例将读取现有 server.xml 当前目录中的文件，附加新服务器并将文件重新写入 server.xml 。没有现有的.xml文件它不起作用，所以你需要修改代码来处理这种情况。

The following complete example will read an existing server.xml file from the current directory, append a new Server and re-write the file to server.xml. It does not work without an existing .xml file, so you will need to modify the code to handle that case.

import java.util.*;
import javax.xml.transform.*;
import javax.xml.transform.stream.*;
import javax.xml.transform.dom.*;
import org.w3c.dom.*;
import javax.xml.parsers.*;

public class AddXmlNode {
    public static void main(String[] args) throws Exception {

        DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
        Document document = documentBuilder.parse("server.xml");
        Element root = document.getDocumentElement();

        Collection<Server> servers = new ArrayList<Server>();
        servers.add(new Server());

        for (Server server : servers) {
            // server elements
            Element newServer = document.createElement("server");

            Element name = document.createElement("name");
            name.appendChild(document.createTextNode(server.getName()));
            newServer.appendChild(name);

            Element port = document.createElement("port");
            port.appendChild(document.createTextNode(Integer.toString(server.getPort())));
            newServer.appendChild(port);

            root.appendChild(newServer);
        }

        DOMSource source = new DOMSource(document);

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

    public static class Server {
        public String getName() { return "foo"; }
        public Integer getPort() { return 12345; }
    }
}

示例 server.xml file：

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Servers>
  <server>
    <name>something</name>
    <port>port</port>
  </server>
</Servers>

您的代码的主要更改是而不是创建新的root元件。上面的示例只使用现有 server.xml 中的当前根节点，然后只需附加一个新的 Server 元素并重写该文件。

The main change to your code is not creating a new "root" element. The above example just uses the current root node from the existing server.xml and then just appends a new Server element and re-writes the file.

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