How to throw Java SAXParseException for bad XML documents in Try/Catch

Question

I am trying to parse elements out of a XML document. It works for most of them, but sometimes I may get a fatal error because I am given a badly formatted XML document. I want to ignore those cases when I get those XML documents by throwing an exception for it. The console gives me a SAXParseException, but when I call for it in the catch block, it is unable to. I wanted to do it in the JSP scriplet, but it will never be thrown since the scriplet is not actively searching for the SAXException.

I though the solution is to create a method to throw the exception, but again, it says that the SAXParseException will never be thrown in the try/catch statement. What is happening here?

public String parseElementsByTagNameInXML(Document doc, String tagName) throws SAXParseException
        {
            try{
                return doc.getElementsByTagName(tagName).item(0).getTextContent();
        }
        catch(SAXParseException e){
             System.out.println("Failure on Generating MessageID: " + e);
        }

        catch(NullPointerException e){
            //will not spam the console with nullpointexception errors
        }
        catch(Exception e){
            System.out.println("Failure on Generating MessageID: " + e);
        }
            return "";
        }

That message is telling your that `doc.getElementsByTagName(tagName).item(0).getTextContent()` will *never* throw `SAXParseException`, so don't bother trying to catch it. When you say you have a "badly formatted XML document", do you mean that it's not well-formed XML, and can't be parsed to a DOM? Or do you mean that well-formed XML structure isn't what you expect (i.e., it's not valid according to your schema)? — erickson, Feb 04 '16 at 20:34
Well, Im doing a basic parser from within Document builder, inputsource, and stringreader set to the XML document. The error that I'm getting says that "[Fatal error] -- The content of elements must consist of well-formed character data or markup" and it says it also threw the SAX exception with the given error... — Jayizzle, Feb 04 '16 at 20:44
I think I've seen the XML in question. It is just a bunch of other completed XML documents pasted into one XML. Complete docs, that being and end, but have another new xml startign on the next line... I can't simply edit that XML doc, its in a database. But I will probally get others like it. — Jayizzle, Feb 04 '16 at 20:45
That's not valid XML, and I don't think that the method you show here is ever called; I believe the exception is thrown when trying to create the `Document` object. You need to break the documents apart and pass one at a time to the XML parser in order to successfully create a `Document` object to pass to this method. — erickson, Feb 04 '16 at 21:38

score 0 · Answer 1 · answered Feb 04 '16 at 20:51

Your method define that it will throws SAXParseException but your try catch is catching and consuming it without tossing it back up the line. Instead, I think it's printing it out. Try removing that catch and the exception catch, then if it fail by SAXParseException, it'll throw it to whoever call that method.

How to throw Java SAXParseException for bad XML documents in Try/Catch

1 Answers1