如何在Java的SAX Parser中解析嵌套元素？

Question

I want to parse an XML file using SAX parser in java with this format :

<Deals>
  <Deal>
   <id> 10</id>
   <title> title </title>
   <city>
     <id> 1 </id>
     ...
   </city>
  </Deal>
  ...
</Deals>

I have a problem to distinguish between the id element of Deal Node and the id element of the city node.

Answer 1

One thing you can do (I've seen it around and used it -- I'm not certain it's the most efficient or effective way, but it works) is to maintain some state in your parser, whether that be a defined set of states, or some boolean flags, that describe where you are in the document. For example, you might have:

boolean inDeals = false;
boolean inDeal = false;
boolean inCity = false;

Then, in your startElement callback, if the start tag is Deals , set inDeals to true. Similarly for Deal and city . In the endElement callback, do the inverse (eg end tag == Deals , set inDeals back to false). In your characters method, or however you're processing the tag, just handle based on the state of the parser at that time. For example:

if(inDeal) {
    if(inCity) {
        cityId = /*the characters*/;
    } else dealId = /*the characters*/;
}