Java project tutorial make login and register form step by step using netbeans and mysql database duration. Use scastie to run singlefile scala programs in your browser using multiple scala compilers. How to convert xml array to json data in scala tag. Because lift applications are written in scala, an elegant jvm language, you can still use your favorite java libraries and deploy to your favorite servlet container and app server. Lift open source software licensed under an apache 2. This action expects a request with a contenttype header of text json or application json and a body containing a json representation of the entity to create. As shown in the previous recipe, this isnt necessary for simple objects, but it is necessary once objects become more complex, specifically once they contain collections. If youre familiar with the play framework, youll know that its common to use a wrapper template around other templates to keep the look and feel of a website consistent. Datasets are similar to rdds, however, instead of using java serialization or kryo they use a specialized encoder to serialize the objects for processing or transmitting over the network. For example, heres a way to create a dataset of 100 integers in a notebook. If you simply want to use lift in your project, add lift as a dependency to your build system or download the jar files directly. Scala to jsvalue conversion is performed by the utility method json. Reading csvexcel files, sorting, filtering, groupby duration. Learn how to configure development environment for developing.
David suggested lift and scala and initial testing proved that we could realize the developer efficiency and backend scalability that we felt was required to. This recipe demonstrates the lift json and gson libraries. We speak with matt cutts about leading the united states digital services and the role software can play in government. While navigating json tree, you retrieve jsvalue, however you may want to convert the jsvalue to a scala type. To begin, lets briefly talk about the shape of every json object. Deploying a scala lift application in an osgi container. As its name implies, mailserver represents the information an email client needs to connect to a server. Parsing json data into an array of objects scala cookbook. Lift application development cookbook by gilberto t. Because lift applications are written in scala, an elegant jvm language, you can.
The easiest way to deploy a war file is using pax webs war extender. This is referred to as deserializing the string into an object. The play json api provides implicit writes for most basic types, such as int, double, string, and boolean. Now that we know how to load a json in scala, lets give few simple example about how to manipulate it. Please see more examples in srctestscala netliftwebjsonqueryexamples. The lift json json parser in liftweb does a good job, too, but returns jobjectlike types instead of raw string or mapstring, object. Resthelper resthelper is a trait provided by lift web framework, which let us create rest api in a simple and beautiful way there are already lots of example of resthelper, but i feel most of those example a little bit long, so ive created a really minimal json rest api of a blog article, which support get post and delete request. Lift json provides several different styles to extract data from json. The following code shows a complete example of how to use lift json to convert a json string into a case class named mailserver.
Finally figured this out after breaking my head over numerous scala json libraries that are not as performant or reliable as jackson. While both encoders and standard serialization are responsible for turning an object into bytes, encoders are code generated dynamically and use a format that allows spark to. You should see the output on console and refreshes as you move the files to a folder. Use the lift json library to convert a json string to an instance of a case class. It uses a json specific bodyparser which will parse the request and provide request. For instance, a user can now say check stock prices, get stock prices, or get stocks to check their stocks. Spark streaming files from a directory spark by examples. A central concept in lift json library is json ast abstract syntax tree which models the structure of a json document as a syntax tree. Json is the circe data type representing a json object. Running and debugging the lift project in scala ide. 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.
Instant lift web applications 20 by torsten uhlmann. Lift in action by tim perrett is available in print and ebook format. When lift parses a request, it splits the request into constituent parts e. When program execution pauses, copymove the files to a folder. For instructions on running and using the project, please see the appendix. 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. The simply functional web framework for scala 2011 by timothy perrett. A very promising project started by the guys from wordnik of swagger fame, it aims to unify scala json asts, sports multiple backends including jackson, and has native support from both scalatra and spray. This simple json example is based on a morecomplicated json example here at. 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. However, one of the things i need is the uri associated with the attribute in the array element that has rel. It turns out that the situation is similar if not worse. The lift json library uses its own dsl for generating json output from scala objects.
Scala is one of the coolest programming languages out there and lift is a. If you want you can also download the sbt plugin for idea. Read on to find out how you can enable and use json in your next play project. This step by step tutorial will explain how to create a spark project in scala with eclipse without maven and how to submit the application after the creation of jar. The following code shows a complete example of how to use liftjson to convert a json string into a case class named mailserver. Im parsing the document using lift json btw, congratulations on a great library. When using foreign key association mapping in a relational database using lift s mapper framework or javas jpa for example, the framework will automatically manage the association object, so. Lift web framework minimal rest api example example. In particular, im trying to parse a json document into scala objects, and im using lift json to do so. Returning json gives an example of accepting and returning json. Scala how to download url contents to a string or file. Lift cookbook a community question and answers book, free at cookbook lift web applications howto by torsten uhlmann is available in print and ebook format. Liftweb setup in 10 minutes ide and project configuration dzone. 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.
Jobject, while using the parse function, it will return a org. Creating a simple scala object from a json string oreilly. Parameter weight added to overloaded version of shortestpathto to enable flexible weight definitions. This guide also briefs about the installation of scala plugin in eclipse and setup spark environment in eclipse. How can i parse json text or a json document with scala. A quick tour of json libraries in scala manuel bernhardt. This example is in scala, but play also has a java api which looks and acts just like the scala api, and has a corresponding playjavarestapi example project in the playsamples repo. Mapping associations with couchdb, scala and lift by aleksa vukotic. Feb 02, 2011 parsing and formatting utilities for json. To demonstrate the lift json library, create an empty sbt test project. Datasets getting started with apache spark on databricks. Recipes from the community for building web applications with scala 20 by richard dallaway. Getting to the point of this post, the following scala source code shows how to read an array of json string values using lift json. Read an overview of how lift achieves these important goals.
To create a new, basic lift application that has some example code, simply execute. 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. Scala json features and performance linkedin slideshare. Xml how to convert xml array to json data in scala. Let me strongly suggest jawn, which supports streaming json parsing using any of a variety of asts. Here are some urls i used to get the correct lift json jar. The operator in the first example transforms tuples in jfields combining them in a list to create a org. Most examples in the following chapters are based on a partial academic library application backed by a graph. You can use json4s, which usually works exactly the same as lift.
First, for primitive types in examples or demos, you can create datasets within a scala or python notebook or in your sample spark application. Graph for scala json is supplied as an extra module jar. The following example demonstrates how to deserialize the string jsonstring into a series of. Since you are familiar with lift json, you may wish to use json4s native module, which is literally just lift json repackaged. With macports, you can get scala using sudo port install scala2. Its basically semistructured data built on top of keyvalue pairs.
To add the xsbtwebplugin download the most recent version of our. How do i download the contents of a url to a string or file in scala. It provides a case class for each of the above mentioned json. Its very useful to be familiar with this data type since its how circe models the base type we want to address.
Json4s is a port of lift json, so it shares the same api. Try to add some cool things with new features of scala 2. The complete example code can be found in the github download it and run sparkstreamingfromdirectory. Almost the simplest possible play framework and scala. For example, you may want a jsstring to be converted to a string, or a jsnumber to be converted to a long.
To do this, i added an array of phrases to the json file that describes the stocks plugin. This page assumes youve installed sbt 1 lets start with examples rather than explaining how sbt works or why. Now lets take a look at how our example from javas stream extensibility, behaves using seq by joo. The examples repository contains the source code for several example lift applications, including demo building lift. What is the scalarific way to grab a value out of this json. Working with json in scala using the json4s library part. Lift application development cookbook 20 by gilberto t. Finding correct jar file to work with scala example stack overflow. These examples are extracted from open source projects.
This is good for pattern matching when you want to change behaviour based on the suffix, but a hindrance in this particular situation. Using json with play and scala using json with javas play framework and scala is a natural fit. Published on 6 november 2015, last updated on 6 june 2018. Parsing json problem with files greater than 100mb. Create spark project in scala with eclipse without maven. Mapping associations with couchdb, scala and lift dzone java. Rest this chapter looks at recipes around rest web services, via lifts resthelper trait. Dzone java zone mapping associations with couchdb, scala and lift. Jul 31, 2016 learn how to read json as file in scala. Use a combination of methods from the liftjson library.