使用 Java 创建多个同名 xml 元素的最佳方法是什么？

Question

Let's say I want to create this xml:

<root>
    <element>
        text 1
    </element>
    <element>
        text 2
    </element>
    <element>
        text 3
    </element>
        .
        .
        .
    n elements
</root>

With a java loop, I having trouble creating it with jdom.element, since at the second iteration, it says that there's already an element called "element", and I have read that once attached, you can't create more of the same element, so use clone or something, but I haven't figure out how, and I believe this should be fairly simple.

int i = 0;
int n = 100;
while(i < n){
    (Missing code)
}

Missing code is what I need.

EDIT: Sorry for being lazy, I've added code to exemplify better what I needed to do, and what worked, but @rolfl understood what I wanted to do and my problem, and he solved it. Thank you. And sorry again everyone for being lazy.

My code:

    Element eElements = new org.jdom.Element("Elements");
    Element eElement;
    Element eSubElement1 = new org.jdom.Element("SubElement1");
    Element eSubElement2 = new org.jdom.Element("SubElement2");

    int i = 0;
    int n = 100;

    while (i < n){
        eSubElement1.setText("Text " + i);
        eSubElement2.setText("Text " + i);
        eElement = new org.jdom.Element("Element");
        eElement.addContent(eSubElement1);
        eElement.addContent(eSubElement2);
        eElements.addContent(eElement);
    }

I thought that calling a new "Element" everytime would be enough, but you have to call new "SubElementX" too.

While loop that worked:

        while (i < n){
        eSubElement1 = new org.jdom.Element("SubElement1").setText("Text " + i);
        eSubElement2 = new org.jdom.Element("SubElement2").setText("Text " + i);
        eElement = new org.jdom.Element("Element");
        eElement.addContent(eSubElement1);
        eElement.addContent(eSubElement2);
        eElements.addContent(eElement);
    }

Answer 1

You are obviously trying to add the same instance multiple times, or something. You should create a new instance of the Element "element" for each value.

Something like:

Element root = new Element("root");
for (int i = 0; i < 100; i++) {
    root.addContent(new Element("element").setText("Text " + i));
}

Then output the root element using XMLOutputter (Use the Format.getPrettyFormat() on your outputter to get nice whitespace in the results.

Answer 2

For XML processing (marshalling/unmarshalling) I would suggest JAXB instead of jdom.

Not knowing your exact use case (I assume it could be more than a simple text, at least in theory), I would use POJOs that represent a xml-element and another POJO that represents the xml-root and basically just holds a list of the xml-element-POJOs.

With that you would populate xml-root-POJO with the xml-element-POJOs in your while-loop and after you are done you hand the xml-root-POJO to JAXB for marshalling it into an xml-file.

In your case, the POJOs may should be annotated like @XmlRootElement(name = "root") and @XmlElement(name = "element")