I want to parse a large xml file(785mb) and write the data to csv. I am getting java heapspace error(out of memory) when I try to parse the file.
I tried increasing the heap size to 1024mb but the code could handle a file of 50mb maximum.
Please let me know a solution for parsing large xml file in java.
You should use a SAXParser instead of a DOMParser
The difference is that it doesn't load the complete XML data in memory.
Look at this tutorial : http://www.mkyong.com/java/how-to-read-xml-file-in-java-sax-parser/
Regards,
Romain.
The solution here is to use Streaming Api for XML (StAX).
Here is good tutorial.
Related
I am using mirth connect 3.0.3 and i am having a .xml file which is almost 85mb size and contains some device information. i need to read this .xml file and insert that data to the database(sql server).
the problem i am facing is when i try to read the data it is showing java heap size error:
i increased server memory to 1024mb and client memory to 1024mb.
but it is showing the same error. if i increase the memory to more, i am not able to start mirth connect.
any suggestion is appreciated.
Thanks.
Is the XML file comprised of multiple separate sections/pieces of data that would make sense to split up into multiple channel messages? If so, consider using a Batch Adapter. The XML data type has options to split based on element/tag name, the node depth/level, or an XPath query. All of those options currently still require the message to read into memory in its entirety, but it will still be more memory-efficient than reading the entire XML document in as a single message.
You can also use a JavaScript batch script, in which case you're given a Java BufferedReader, and can use the script to read through the file and return a message at a time. In this case, you will not have to read the entire file into memory.
Are there large blobs of data in the message that don't need to be manipulated in a transformer? Like, embedded images, etc? If so, consider using an Attachment Handler. That way you can extract that data and store it once, rather than having it copied and stored multiple times throughout the message lifecycle (for Raw / Transformed / Encoded / etc.).
We are building search feature in our application to traverse over more than 100,000 xml files for content.
Data content are in form of huge number of xml files.
Is this a good idea to keep huge number of xml files and on search (like by name etc) traverse through each file for result? It may reduce our application search performance.
Or what is the best way?
You want elasticsearch here. It will give you what you need.
I have a xml file that is on this link
http://nchc.dl.sourceforge.net/project/trialxml/options.xml
I have downloaded and parsed it successfully and also made a dynamic UI, but I have not used any of the predefined functions like getFirstChild(), getNextSibling() which makes my parser incompatible of parsing complex XML files having around 6-7 levels of menus.
Please help how to traverse a XML file,and dynamically create a UI.
Try using DOM parser, to parse your xml document
See this link for further details:
http://tutorials.jenkov.com/java-xml/dom.html
I want to save an RSS feed to an xml document on my computer. I'm using XPath with Java to parse the XML myself, so all I want is a file that contains the source (XML) I see when I view the source of the website's RSS page.
In other words, instead of copying and pasting the source of the RSS page into a file I save as an XML file, I'd like to write a program that pulls this for me.
You don't even need to introduce a library to do that!
Simply get an URL-object on the Rss-Feed you want to "download" and use the openConnection()-method to get an URLConnection.
You can then use it's getInputStream()-method. From this InputStream you can read the unparsed source of the RSS document (you should wrapp it with a BufferedInputStream).
This can then be saved as a String (in memory) or directly written to the HDD by using a FileOutputStream.
An example-implementation can be found here: https://gist.github.com/2320294
You can use Apache commons HttpClient to get the file from the web. The usage of this library is very convenient. Here's the official tutorial.
More specifically large XML webpages (RSS Feeds). I am using the excellent Rome library to parse them, but the page I am currently trying to get is really large and Java runs out of memory before getting the whole document.
How can I split up the webpage so that I can pass it to XMLReader? Should I just do it myself and pass the feeds in parts after adding my own XML to start and finish them?
First off learn to set the java command line options for Xms and Xmx to appropriate values, all the DOM based parsers each crap loads of memory. Second look at using a Pull Parser, it will not have to load the entire XML into a document before processing it.