如何在java中将节点附加到现有的XML文件

How do I append a node to an existing XML file in java

提问by stackoverflow

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);
}

This is the function I need help with:

这是我需要帮助的功能：

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);
}

Original:

原来的：

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

Wanted:

通缉：

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

采纳答案by andyb

The following complete example will read an existingserver.xmlfile 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.

以下完整示例将从当前目录读取现有server.xml文件，附加一个新服务器并将文件重新写入server.xml. 如果没有现有的 .xml 文件，它就无法工作，因此您需要修改代码来处理这种情况。

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; }
    }
}

Example server.xmlfile:

示例server.xml文件：

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

The main change to your code is notcreating a new "root" element. The above example just uses the current root node from the existing server.xmland then just appends a new Serverelement and re-writes the file.

对代码的主要更改不是创建新的“根”元素。上面的例子只是使用现有的根节点server.xml，然后只是附加一个新的Server元素并重新写入文件。

回答by Sergii Zagriichuk

If you need to insert node/element in some specific place , you can to do next steps

如果您需要在某个特定位置插入节点/元素，您可以执行后续步骤

1. Divide original xml into two parts
2. Append your new node/element as child to first first(the first part should ended with element after wich you wanna add your element )
3. Append second part to the new document.

1. 将原始xml分成两部分
2. 首先将你的新节点/元素作为子节点附加到第一个（第一部分应该在你想要添加元素之后以元素结束）
3. 将第二部分附加到新文档。

It is simple algorithm but should works...

这是一个简单的算法，但应该有效......

回答by Omnaest

You could use DOM4jdoing that.

你可以使用DOM4j 来做到这一点。

回答by Alvin

You can parse the existing XML file into DOM and append new elements to the DOM. Very similar to what you did with creating brand new XML. I am assuming you do not have to worry about duplicate server. If you do have to worry about that, you will have to go through the elements in the DOM to check for duplicates.

您可以将现有的 XML 文件解析为 DOM 并将新元素附加到 DOM。与您创建全新 XML 时所做的非常相似。我假设您不必担心重复的服务器。如果您确实必须担心这一点，则必须遍历 DOM 中的元素以检查重复项。

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

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

Element root = document.getDocumentElement();

for (Server newServer : Collection<Server> bunchOfNewServers){
  Element server = Document.createElement("server");
  /* create and setup the server node...*/

 root.appendChild(server);
}

/* use whatever method to output DOM to XML (for example, using transformer like you did).*/

回答by silentkratos

To append a new data element,just do this...

要附加新的数据元素，只需执行此操作...

Document doc = docBuilder.parse(is);        
Node root=doc.getFirstChild();
Element newserver=doc.createElement("new_server");
root.appendChild(newserver);

easy.... 'is' is an InputStream object. rest is similar to your code....tried it just now...

容易.... 'is' 是一个 InputStream 对象。其余与您的代码相似....刚刚尝试过...