在java中附加到xml文件中 [英] Append into xml file in java

问题描述

File file = new File("E:\\file.xml");

JAXBContext jaxbContext = JAXBContext.newInstance(Customer.class);

Marshaller jaxbMarshaller = jaxbContext.createMarshaller(); 

jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);

jaxbMarshaller.marshal(customer, file);     

jaxbMarshaller.marshal(customer, System.out);

我可以创建文件，但下次想要追加xml而不是创建。

I am able to create file ,but next time want append into xml not create.

推荐答案

这个java代码用于将新节点附加到xml文件......它基于DOM

this java code works to append new node to the xml file......it is based on DOM

import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import java.io.FileOutputStream;
public class writexml1 {

public static void main (String args[]) 
{

File docFile = new File("..\\jquery\\WebContent\\demo\\testing.xml");

Document doc = null;
try 
{
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
doc = db.parse(docFile);
} 
catch (java.io.IOException e) 
{
System.out.println("Can't find the file");
} 
catch (Exception e) 
{
System.out.print("Problem parsing the file.");
}

Element root = doc.getDocumentElement();

System.out.println("The root element is " + root.getNodeName() + ".\n");

NodeList children = root.getChildNodes();
System.out.print("There are "+children.getLength()+" child elements.\n");
System.out.print("They are: \n");

//Print the file 
for (Node child = root.getFirstChild();child != null;child = child.getNextSibling())
{
if (child.getNodeType() == child.TEXT_NODE)
{
System.out.println("Text: "+child.getNodeValue());
} 
else if (child.getNodeType() == child.ELEMENT_NODE) 
{
System.out.println(child.getNodeName()+" = "+child.getFirstChild().getNodeValue());
}
}


//NodeList deleteElement = root.getElementsByTagName("staff");

//Node deleteNode= deleteElement.item(0);

//root.removeChild(deleteNode); 
Element staffElement = doc.createElement("staff");

Node updateText = doc.createTextNode("");
staffElement.appendChild(updateText);
//
Element firstName = doc.createElement("firstname");
String str_firstName="added firstname";
Node firstNameNode = doc.createTextNode(str_firstName);
firstName.appendChild(firstNameNode);

staffElement.appendChild(firstName);

//

Element lastName = doc.createElement("lastname");
String str_lastName="added lastname";
Node lastNameNode = doc.createTextNode(str_lastName);
lastName.appendChild(lastNameNode);

staffElement.appendChild(lastName);


//
Element nickName = doc.createElement("nickname");
String str_nickName="added nickname";
Node nickNameNode = doc.createTextNode(str_nickName);
nickName.appendChild(nickNameNode);

staffElement.appendChild(nickName);


//
Element salary = doc.createElement("salary");
String str_salary="$10,000";
Node salaryNode = doc.createTextNode(str_salary);
salary.appendChild(salaryNode);

staffElement.appendChild(salary);


//
root.appendChild(staffElement);

//Node StaffNode=(Node)updateElement;





try{
String outputURL = "..\\jquery\\WebContent\\demo\\testing.xml";

DOMSource source = new DOMSource(doc);
StreamResult result = new StreamResult(new FileOutputStream(outputURL));

TransformerFactory transFactory = TransformerFactory.newInstance();
Transformer transformer = transFactory.newTransformer();

transformer.transform(source, result);

} catch (Exception e) {
e.printStackTrace();
}

}   
   }

或

您应该查看JAXB API。如果我理解正确，你的xml看起来像这样：

you should check out the JAXB API. If I understand right, you're xml looks like this:

<B>
    <C>11</C>
    <D>21</D>
    <E>31</E>
</B>

所以代码是：

import javax.xml.bind.JAXBContext;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAccessType;

@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class B {
    @XmlElement public String C; // sloppy, probably should be type Integer or something
    @XmlElement public String D;
    @XmlElement public String E;
}

// then, somewhere else in your code you want to serialize...
B b = new B();
b.C = "11";
b.D = "21";
b.E = "31";

JAXBContext c = JAXBContext.newInstance(B.class);

// where w is a Writer instance
c.createMarshaller().marshal(b, w);

这篇关于在java中附加到xml文件中的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！