Re: problem with Crimson parser
Simon Brooke wrote:
in message <1163917880.942213.272070@h54g2000cwb.googlegroups.com>, gk
('srcjnu@gmail.com') wrote:
".....Crimson parser is bundled by default with JDK 1.4.To override
this parser we need to run our example with -Djava.endorsed.dirs
option....."
(1) why people dont want to use Crimson parser ?
I do use it, but it's old and no longer really supported so I ought to sort
out the problems I'm having with Xerces.
(2) according to above comment , so we can run like this..
java -classpath .; -Djava.endorsed.dirs=c:\xerces\lib SAXParserExample
what does "-Djava.endorsed.dirs" do ? it says "override" ....how
does JVM identifies it ? does it searches the "c:\xerces\lib"
directory and try to match whether there is a similar kind of API
already exists in JDK or not ? if it finds , then it overrides with
the new one ......does it work this way ?
Pass.
(3) ok, we can override the XML parser for JVM as above....but how do
we do it , when its an web application.
Drop you preferred parser's JAR file into WEB-INF/lib, set up a
context-param to say which parser you want to use:
<context-param>
<param-name>dom_implementation_class</param-name>
<param-value>
org.apache.crimson.tree.DOMImplementationImpl </param-value>
<description>The DOM implementation to use. I'm currently supplying
Crimson with PRES rather than Xerces, because it
works better. </description>
</context-param>
ok. fine.....but you are using one particular class here this
way.....the JAR file might have many *dependent* class files .....those
also needs to be added ...is not it ? otherwise ,you will get
classnotfoundexception very soon ...and if i try to find which are the
classes which are associated with the desired one ...then i have to
dig up really which is messy and pathetic.
Read that parameter and instantiate the parser you want:
String s = config.getValueAsString( "dom_implementation_class" );
if ( domImp == null )
{
try
{
if ( s != null )
{
domImpName = s;
}
domImp =
(DOMImplementation) Class.forName( domImpName )
.newInstance( );
}
catch ( Exception any )
{
throw new InitialisationException( "Could not find DOM " +
"implementation " + domImpName );
}
}
For example, i have a server which has a XML parser shipped with it
.....but i am using "xerces" ..... in this case , how do i override it
and where to override it ? how can i reject the parser shipped with the
server and adopt the new one which i am using ?
what is the command for that ?
I am not specifying the server name . because , if i say Tomcat ...then
you might say, delete the JAR files from servers lib directory (really,
is it a solution ?) and it will automatically picks up your new JAR
file "xerces"....but there must be some other way out without deleting
the JAR files shipped with the server.....is not it ?
It would be a solution to replace the jar file in the server lib directory,
but I wouldn't do that, because other webapps on the same server may
prefer the default setup. Instead, put the jar file you want in your own
webapp's lib directory, as I've suggested above.
ah ,i see . so you want to say there wont be any conflict if i put my
parser JAR file in my web-app directory.
or in other words , if i put the JAR file in my web-app's WEB-INF/lib
directory then default set-up would be deactivated and the new one
would be picked up . i dont think in this case ,i need extract the
class value and instantiate as you shown above ..right ? because
classes will be automatically loaded by the server's classloader as
these are in the classpath.
--
simon@jasmine.org.uk (Simon Brooke) http://www.jasmine.org.uk/~simon/
Due to financial constraints, the light at the end of the tunnel
has been switched off.