如何解析此XML文件

Question

I am new to programming in java and i have just learned how to parse an xml file. But i am not getting any idea on how to parse this xml file. Please help me with a code on how to get the tags day1 and their inner tags order1,order2

<RoutePlan>
<day1>
    <Order1>
    <customer> XYZ</customer>
    <address> INDIA </address>
    <data> 10-10-2011 </data>
    <time> 9.30 A.M </time>
    </Order1>

    <Order2>
    <customer> ABC </customer>
    <address> US </address>
    <data> 10-10-2011 </data>
    <time> 10.30 A.M </time>
    </Order2>
</day1>

I wrote the following code to retrieve. But i am only getting the data in order1 but not in order2

DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
      DocumentBuilder db = dbf.newDocumentBuilder();
      Document document = db.parse(file);
      document.getDocumentElement().normalize();
      System.out.println("Root Element: "+document.getDocumentElement().getNodeName());
      NodeList node =  document.getElementsByTagName("day1");

      for(int i=0;i<node.getLength();i++){
          Node firstNode = node.item(i);
          Element element = (Element) firstNode;
          NodeList customer = element.getElementsByTagName("customer");
          Element customerElement = (Element) customer.item(0);
          NodeList firstName = customerElement.getChildNodes();
          System.out.println("Name: "+((firstName.item(0).getNodeValue())));

          NodeList address = element.getElementsByTagName("address");
          Element customerAddress = (Element) address.item(0);
          NodeList addName = customerAddress.getChildNodes();
          System.out.println("Address: "+((addName.item(0).getNodeValue())));

          NodeList date = element.getElementsByTagName("date");
          Element customerdate = (Element) date.item(0);
          NodeList dateN = customerdate.getChildNodes();
          System.out.println("Address: "+((dateN.item(0).getNodeValue())));


          NodeList time = element.getElementsByTagName("time");
          Element customertime = (Element) time.item(0);
          NodeList Ntime = customertime.getChildNodes();
          System.out.println("Time: "+((Ntime.item(0).getNodeValue())));
      }

Answer 1

I can give you not one, not two, but three directions to parse this XML (there are more but let's say they are the most commons ones):

• DOM -> two good resources to start : here and here
• SAX -> quickstart from official website: here
• StAX -> a good introduction: here

Judging by the size of your XML document, I'd probably go for a DOM parsing, which gonna be the easiest to implement and to use (but if you have to deal with larger files, take a look at SAX for reading-only manipulations and StAX for reading and writing ones).

Answer 2

The reason you are getting only "Order1" elements is because:

• You lock on the "day1" node.
• You retrieve the "customer" elements by tag name which returns 2 elements.
• You retrieve the first element and print its value and hence the second "customer" is ignored.

When working with DOM, be prepared to spin up multiple loops for retrieving data. Also, you are a bit misguided when it comes to representing your schema. You really don't need to name "elements" as "day1"/"order1" etc. In XML, that can be simply expressed by having multiple "day" or "order" elements which in turn automatically enforces ordering. An example XML would look like:

<route-plan>
    <day>
        <order>
            <something>
        </order>
    </day>
    <day>
        <order>
            <something>
        </order>
    </day>
</route-plan>

Now retrieving "day" elements is a simple matter of:

• Look up "day" elements by tag name
• For each "day" element
  • Look up "order" element by tag name
  • For each "order" element
    • Print out the value of "customer"/"address" etc.