从xml到Java读取子节点的内容

Question

I have been trying to read this xml and fetch the values of id,active and MAIN_ID and store to string values in java as i need to process each values further. But i could read the Node document ,but iam not sure how to get the values of id ,active and MAIN_ID when we loop though the document. Can someone give me ideas to parse this xml and best way to do it.

<add>
<document>
  <field name='id'>Summer id</field>
  <field name='active' update='add'>yes</field>
  <field name='MAIN_ID' update='add'>34242</field>
</doc>
<document>
  <field name='id'>winter id</field>
  <field name='active' update='add'>yes</field>
  <field name='MAIN_ID' update='add'>5354</field>
</document>
<doc>

Right now this is my code .But iam not sure to retrive the child nodes based on fields.

DocumentBuilder builder = factory.newDocumentBuilder();

        // create a new document from input stream and an empty systemId
        Document doc = builder.parse(url);

        // get the first element
        Element element = doc.getDocumentElement();
        System.out.println("element" + element);

        // get all child nodes
        NodeList nodes = element.getChildNodes();

        // print the text content of each child
        for (int i = 0; i < nodes.getLength(); i++) {
            Node node = nodes.item(i);
            if (node instanceof Element) {
                //need to know how to parse the child elements for above code
            }
        }

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

Answer 1

First consider not using attributes in XML to specify node meaning, so instead have something like this

...
<document>
  <id>winter id</id>
  <active update='add'>yes</active>
  <MAIN_ID update='add'>5354</MAIN_ID>
</document>
...

If your document is large, consider learning about and using a SAX parser. However if you want to use DOM, look at the org.w3c.dom.Element interface. There are lots of step by step posts on SO on how to parse HTML using DOM, like this one . But you want getElementsByTagName for elements named "document", then pull the individual fields from that Element using the same methods to get id, active, etc.