Programmer Group

1.1. Course objectives1.1.1. Objective 1: familiar with Scala Actor concurrent programming1.1.2. Goal 2: prepare for Akka learning Note: Scala Actor is scala 2.10.x and earlier. Scala added Akka as its default Actor in version 2.11.x, and the old one has been abandoned. 1.2. What is Scala actor 1.2.1. Concept The Actor in scala can realize the ...

Article directory Preface pom Dependent Version Dome Preface There are some cases on the Internet about setting offset manually in kafka, but most of them use 0.8 version of kafka, which is written by scala. The version of kafka-0.10 is rarely mentioned or incomplete. Version 0.10 is compatible ...

1. Declare variables package cn.itcast.scala object VariableDemo { def main(args: Array[String]) { //Variable values defined with val are immutable, equivalent to variables modified with final in java val i = 1 //Variables defined with var are changeable, and val is encouraged in Sc ...

Implicit transformation and implicit parameters are two very powerful functions in Scala. With implicit transformation and implicit parameters, you can provide elegant class libraries and hide boring details from the users of class libraries. Implicit enhancements of class methods enrich the functions o ...

Spark Streaming provides two types of built-in streaming media sources. Basic source: The source directly provided in the StreamingContext API. Example: File system and socket connection. Advanced resources: Kafka, Flume, Kinesis and other resources can be obtained through additional utility classes. ...

Links to the original text: https://my.oschina.net/asparagus/blog/699814 Spark saves the output data to an existing directory Save by the saveAsTextFile method of RDD String input =  ...

Article Directory Introduction to Akka Concurrent Programming Framework Introduction to Akka Akka characteristics Akka communication process Create Actor Introduction to API Getting Started Cases Implementation Steps 1. Create Maven modules 2. Create and load Actor s 3. Send/receive messages Akka ...

Data sources can be created by Stream Execution Environment. addSource (sourceFunction). Flink also provides some built-in data sources for easy use, such as readTextFile(path) readFile(), and of course, it can also write a custom data source (by implementing the SourceFunction method, but can not be implemented in parallel). That's ok. Or impl ...

1. Implicit Conversion 1 Basic Introduction Implicit conversion functions are functions declared with a single parameter using the implicit keyword.This function is automatically applied to convert values from one type to another (2) Examples obj ...

Articles Catalogue 9.1 Pack 9.2 Scope 9.3 Package Objects 9.4 Packet Visibility 9.5 Introduction 9.6 Rename and Hide Method 9.1 Pack Packets, like packages in Java, are designed to organize programs, and packages in Scala do not require associations between directories and packages. The package ...