scala mongodb tutorial

+ ")" ) }} The Talkpoint class above inherits from point, noting that its default constructor, X, Y does not have a Val decoration before, and extends point (x, y) will automatically call the base class's constructor. We can call this subclass's Talk method by using the following codeObject app { def Main (args : Array[string]) { val P = new talkpoint (0,0 p. () }} Run the program output: My position is (0,0)Methods for overriding base classesNext we create a subclass of Talkpoin

JAVA_HOME environment variable and add the JDK's Bin directory to the path variable. To verify that you can work, at the command prompt, type: java-version, and then press ENTER. You should see something similar to the following: C:>java-version Java Version "1.6.0_15" Java (TM) SE Runtime Environment (build 1.6.0_15-b03) Java HotSpot (TM) 64-bit Server VM (build 14.1-b02, Mixed mode) C:> Next, test to see if the Java compiler is installed. Enter Javac-version. You should see something s

Scala Operation MongoDBMavenDependencies> Dependency> groupId>Org.mongodbgroupId> Artifactid>CasbahArtifactid> version>3.1.1version> Dependency>Dependencies>SbtLibrarydependencies + = "Org.mongodb" percent "Casbah"% "3.1.1"LibImport Com.mongodb.casbah.imports._CONNECTIONVal mongoclient= mongoclient ("localhost", 27017= Mongoclienturi (" mongodb://localhost:27017/ " = mongoclient (URI)Use COLLE

===========================================Original link: Scala to MongoDB additions and deletions to the operation reproduced please specify the source! ===========================================Environment dependent: jdk1.8, Scala 2.12, IdeaMongoDB driver:3.1.1. Note that the MONGO for Scala driver involves multip

Scala Tutorial (12) List Operation Advanced Advance combat 1 List Basic Operation 1.1 List Composition Structure The array is composed of the head tail two parts: head represents the first element, and tail represents the other elements. Val bigdata = List ("Hadoop", "Spark") val data = List (1,2,3) //array consists of head tail two parts: head represents the first element, tail represents

To create a string: The most straightforward way to create a string is to write a method that: var greeting = "Hello world!"; Or var greeting:string = "Hello world!"; Whenever you encounter a string in code, the compiler creates a string object and its value in this example using: "Hello world!", but if you like, you can give the string, because here I have alternately shown in the declaration. Object Test { Val greeting:string = "Hello, world!" def main (args:array[string]) { printl

Previous Article: Scala Tutorial: interaction with Java, everything is an object This document is translated from the official Scala tutorial. to prevent misunderstanding, keep the original document for reference. Due to space limitations, there are three articles. Blog formats are not easy to adjust, interested friend

Video materials are checked one by one, clear high quality, and contains a variety of documents, software installation packages and source code! Perpetual FREE Updates!Technical teams are permanently free to answer technical questions: Hadoop, Redis, Memcached, MongoDB, Spark, Storm, cloud computing, R language, machine learning, Nginx, Linux, MySQL, Java EE,. NET, PHP, Save your time!Get video materials and technical support addresses----------------

option.16. Added some development issues.1] Skip + limit page flip, the more slow the back, some materials say that using the array element paging can solve, not yetI tried it. The more reliable method is to first find the ID of the last time and do not use skip when turning pages:Last_row_id = objectid ('....');DB. activity_stream-> Find ({_ ID: {$ LT: last_row_id },User_id: 20}). Sort ({_ ID:-1}). Limit (10 );2]. select only the fields that are actually needed3]. When updating a piece of data

Linux mongodb installation and data import and export tutorial, mongodb Import and Export How to install mongodb and import and export data in Linux # Viewing the linux release version Cat/etc/issue # View the Linux kernel version Uname-r 1. General steps for installing mongodb