iam a beginner in hadoop,can any one help me in reading json in mapreduce job.
i have googled and found jaql is suitable for reading json.but i didnot find any documentaion on how it could be implemented in our map reduce job.
is there any other framework which supports reading json in map reduce?
any suggestions on this?
Thanks in Advance
I would rather trust the MapReduce framework itself to handle this. MapReduce allows us to write custom Inout/Output Formats to handle data which is not supported by it OOTB, like JSON. See this question for an example. I would prefer this as I won't require any third party stuff for this. It's just a matter of extending the MapReduce API(But it's just my choice. Other's may find something else more suitable).
But, the easiest way, IMHO, would be to use Hive or Pig to handle JSON data. You don't have to do much in order to make it work, as both these project have OOTB JSON support. See this for Hive-JSON SerDe and this for Pig's JsonLoader and JsonStorage.
HTH
Related
Hello there I am creating an application in Flutter and I am receiving JSON response from the API and I know that we need to parse the response to use in the Flutter app but I found that if we use the normal way as:
jsonData['key'] to get and show the data because this way you can handle any kind of response easily but when I am using the models way then I am facing a lot of issues in which the data structure and data types included.
and I think the model only provides an object structure in which you can access data as an object way like jsonData.key instead of the jsonData['key'] this is only my thinking you can correct me if I am wrong here.
I just want to know that if I am using a non-model way then will it affect my app or not?
models are not resiliant. Your code will always break if the api is modified.
Use an Object is a good practice because helps to take advantage of the strong typed language. This allows you to have a better debug process, catch potential error during writing time (and in compilation time). And this is independent of the state management package that you choose.
Firstly, this has nothing to do with getX. Parsing json into models is much cleaner. You can compare two objects but how do you compare two jsons?
And if you need to create an instance of the object, how would you do so without a model? How would you pass it to another class or a function? I think the answers to this questions will solve your dilemma.
I'm working on a project that uses parallel methods to convert text from one form to another. We're going to implement a CSV to JSON converter to demonstrate the speedups that are possible using our parallel framework.
We want to benchmark our converter once it's finished. What are the fastest libraries/stand-alone programs/etc out there that are capable of doing CSV-JSON conversion? I found a list of potential candidates here:Large CSV to JSON/Object in Node.js, but I'm not sure how fast the listed options are. In the worst case I'll benchmark them myself, but if someone already knows what the "best in class" converters are it'd save me some time.
Looks like the maintainer of csvtojson has developed a benchmark application. I think I can add my csv to json converter to his benchmark project to test my converter.
if your project can consider in-browser apps, I suggest csvtojson as it is by far the speediest converter on the market as of 2017.
I created it myself so I may be a bit biaised, but I specifically developed it for a bigger project that required big csv to json crunching.
Tell me if it served.
I was reading this article about protobuf and I wondered where to use it in the projects. I read some articles that said google created protobuf to replace XML, but as far as I know in 2008 (the first release) JSON was already there.
I searched more and I found an article that the writer suggested to use it instead of JSON, but I still don't get the idea completely.
So where shall I use it? Any special scenario, or like JSON whenever that I want to transport data? Any other scenarios?
It is useful whenever you want to serialize/deserialize your data. Typical situations include sending your data to someone else over the network, storing it to disk or keeping it in context while performing asynchronous processes.
Here is a brief explanation about the main differences between protocol buffer, json and XML: https://stackoverflow.com/a/14029040/6681872
I have somewhat unique requirement, which I could not find an answer to so far. I need a JSON to JSON transformation. Preferably, if I could plug it into Apache Camel, that would be wonderful.
As a side note, I would also welcome any suggestion to optimally store the JSON to JSON mapping. Is there any XSLT-based way of achieving this?
Thanks!
Mario
ZORBA with jsonIQ : http://www.jsoniq.org/
it's a native library, but with high performance. You have examples in the web page.
There is a simple design here: https://rawgithub.com/chunqishi/edu.brandeis.cs.json2json/master/docs/design-2014-04-09.html
May be you can improve it by source code, https://github.com/chunqishi/edu.brandeis.cs.json2json.
I know this is an old question, but to refresh the answers, starting from Camel 2.16 there is a new component for JOLT integration. It is very powerful !
Would you have any hints on what would be the best way to deal with files containing JSON entries and Hadoop?
There's a nice article on this from the Hadoop in Practice book:
http://java.dzone.com/articles/hadoop-practice
Twitter's elephant-bird library has a JsonStringToMap class which you can use with Pig.
Try this
You can also use JAQL. Its the easiest way to deal with JSON in Map Reduce. Bad thing is that you will have to learn JAQL (unless you know it already) !!
MongoDB is a good option when you are dealing with JSON. MongoDB and Hadoop are a powerful combination and can be used together to deliver complex analytics and data processing for data stored in MongoDB. http://www.mongodb.org/