Scala parse json example download

Scala xml processing literals, serialization, parsing. This functionality depends on a converter of type writest which can convert a t to a jsvalue. We were working on a spark job to read json files out of hdfs, and it seemed to be running way too slowly. Heres an example of a class that extends regexparsers, which is a subtrait of parsers. The following code shows a complete example of how to use lift json to convert a json string into a case class named mailserver. Ide ce community edition, please download the play scala starter.

Introduction to the scala parser and combinators dzone java. Lots of web services and server backends now expect requests to be formatted as json. To manage sprayjson with sbt managed library dependencies. The play json library basics overview the recommended way of dealing with json is using plays typeclass based json library, located at play. I parse extract that json string into an instance of my mailserver class. How to parse json data in a text file using apache spark and. Parsing json problem with files greater than 100mb. Creating a simple scala object from a json string oreilly. Parser class that looses information whether list or object was parsed.

Im trying to dig into scala a bit more, and one of the common exercises i do is to read in some json being a common interchange format these days and persist a simple map back out to json. There are a lot of libraries for working with json. A scala json array parsing example using lift json. The previous tutorial covered basic xml processing in scala, but as i noted, xml is not the primary choice for data serialization these days.

Using implicit formats, everything happens behind the scenes. To manage spray json with sbt managed library dependencies. Scala to jsvalue conversion is performed by the utility method json. The following code shows a complete example of how to use liftjson to convert a json string into a. It turns out that the situation is similar if not worse read more. Spark read and write json file into dataframe spark by. Create a json object string with gson and scala or java. First, heres the scala source code for my example, and then a description will follow. Contribute to dblockscalaparsejson development by creating an account on github. One of the things im doing here is to parse some of the json text into an array of objects, in this case an array of string objects.

Five good ways and two bad ways to read large text files with scala. Nodeseq nodeseq this makes it easy to iterate over the results when elements are found, and when theyre not found. At this moment the approach taken to working with the ast has been taken from liftjson and the native package is in. How can i construct and parse a json string in scala. You need to parse these files and combine the data in two files to check how many asset impressions, views and clicks are present in both the files for each page view id. This tutorial will walk you through how to work effectively with json data in scala, walking through a few common workflows on a piece of realworld json data. This might be the case with json to, but im not sure since i havent written a json parser for large json yet. Haoyi is a software engineer, and the author of many opensource scala tools such as the ammonite repl and the mill build tool. Scala to jsvalue conversion is performed by the utility method jsonttimplicit writes. Parse json to object models in scala using playjson dev. You can convert any object to json and of course do it in reverse. Htmlcleaner actually, a nice thing about scala is that you can have that import statement in your function, but i havent started following that practice yet.

As its name implies, mailserver represents the information an email client needs to connect to a server. Getting started with scala parser combinators dzone java. Files with nested json objects, one per line, with both string and numeric values so basically a mapstring, any. This is referred to as deserializing the string into an object. Parse json directly into a case class stack overflow. Parsing real world html with scala, htmlcleaner, and stringescapeutils. Example of using the scala sprayjson parser to parse a complex. Apr 23, 2020 to support multiple scala versions, see the example in scala scala moduledependencysample. Example of using the scala spray json parser to parse a complex json structure. Home scala scala xml processing literals, serialization, parsing, save and load examples xml is a form of semi structured data which is organized in the form of trees. In particular, im trying to parse a json document into scala objects, and im using liftjson to do so. A quick tour of json libraries in scala manuel bernhardt.

Read on to find out how you can enable and use json in your next play project. These examples are extracted from open source projects. Would have saved me a day or two of trying them all out especially play json and json4s if had found this earlier. The play json api provides implicit writes for most basic types, such as int, double, string, and boolean. The following code shows a complete example of how to use liftjson to convert a json string into a case class named mailserver.

Using json with play and scala using json with javas play framework and scala is a natural fit. To start writing a parser with the scala parsing library, we write a class that extends the parsers trait. I define a string named json, which contains my json content. How to work with json in scala haoyis programming blog. The benefit of this approach is that both the java and the scala side of play can share the same underlying library jackson, while scala users can. I created the forecast variable by specifying the full path to the tag attributes, but you can simplify the expression by using \\ instead of \. Create two different sample files multiline and single line json file with above mentioned records copypaste. Fix attached to ticket is trivial but makes json api backward incompatible, unless different parsers will be used for method json. Scala xml processing literals, serialization, parsing, save and load examples xml is a form of semi structured data which is organized in the form of trees. Parsing real world html with scala, htmlcleaner, and. It will parse the expression if the expression contains a number followed by a symbol followed by another number. Use the lift json library to convert a json string to an instance of a case class. Example of using the scala sprayjson parser to parse a complex json structure.

I parseextract that json string into an instance of my mailserver class. How to parse json data in a text file using apache spark. Gson this is the rough equivalent of a java pojo class. Easily update selected elements of the immutable sprayjson representation. So, here are some notes to help others navigate the. Deeper xml parsing, and extracting xml tag attributes. Easy json unmarshalling in scala with jackson example. Contribute to tethysjsontethys development by creating an account on github. As soon as you have a type class able to transform the scala type to json, it is pretty easy to generate any scala value to json. If the json maps directly to a class, we provide a handy macro so that you dont have to write the readst, writest, or formatt manually.

They are not according to crockfords original rfc 4627. You might want to look at a library or a method to do something to the json on parse time, instead of loading the entire thing in memory first. Contribute to dblockscala parsejson development by creating an account on github. If you know scala and are familiar with json, there isnt much to say about this example. Parse incoming request bodies in a middleware before your handlers, available under the req. Scala xml processing literals, serialization, parsing, save. Use the liftjson library to convert a json string to an instance of a case class.

At this moment there are at least 6 json libraries for scala, not counting the java json libraries. Names used in this example is just sample names, you can change it according to your us. Easily update selected elements of the immutable spray json representation. The following example demonstrates how to deserialize the string jsonstring into a series of emailaccount objects, printing each object as it is deserialized. Finally figured this out after breaking my head over numerous scala json libraries that are not as performant or reliable as jackson. Parsing json data into an array of objects problem you have a json string that represents an array of objects, and you need to deserialize it into objects you selection from scala cookbook book. Create queries similar to xpath in a native scala dsl.

This can convert arrays of strings containing xml to arrays of parsed structs. So, here are some notes to help others navigate the scala json parsing landscape, where there are at least 6 different libraries on both performance and correctness. In play json api, reads converters are used to convert a jsvalue to a. This function works by using the java htmlcleaner library, so youll need to download their jar file, and have this include in your code. They attempt to clean up the html so you can parse it.