SAX XML Java Entities problem

问题

I've a problem with SAX and Java.

I'm parsing the dblp digital library database xml file (which enumerates journal, conferences, paper). The XML file is very large (> 700MB).

However, my problem is that when the callback characters() returns, if the string retrieved contains several entities, the method only returns the string starting from the last entity characters found.

i.e.: Rüdiger Mecke is the original author name held between <author> tags

üdiger Mecke is the result

(The String returned from characters (ch[], start, length) method).

I would like to know:

1. how to prevent the PArser to automatically resolve entities?
2. how to solve the truncated characters problem previously described?

回答1:

characters() is not guaranteed to return of all the characters in a single call. From the Javadoc:

The Parser will call this method to report each chunk of character data. SAX parsers may return all contiguous character data in a single chunk, or they may split it into several chunks.

You need to append the characters returned in all of the calls, something like:

private StringBuffer tempValue = new StringBuffer();

startElement()
{
    tempValue.setLength(0); // clear buffer...
}

characters(characters(char[] ch, int start, int length)
{
    tempValue.append(ch, start, length); // append to buffer
}

endElement()
{
    String value = tempValue.toString(); // use characters in buffer...
}

回答2:

1. I don't think you can turn off entity resolution.

2. The characters method can be called multiple times for a single tag, and you have to collect the characters across the multiple calls rather than expecting them all to arrive at once.

来源：https://stackoverflow.com/questions/4556086/sax-xml-java-entities-problem