gradle

java plugin

1. package into jar file

   • adds a task jar(./gradlew jar)
   • adds compiled classes and resources into jar achieve
   • name of jar : project-name-version.jar

2. easily run tests

   • adds a task test(./gradlew test)
   • compiles tests, processes resources, run tests
   • creates a test report!

3. define dependencies

   • use the dependencies section of build.gradle

   
   

   • dependency configuration

     implementation
     testImplementation

   • dependency configuration used to generate classpath

Gradle Java project layout

• src/main/java

  • build/classes/java/main

• src/main/resources

  • build/resources/main

• src/test/java

  • build/classes/java/test

• src/test/resources

  • build/resources/test

• everythings is configurable

example Of gradle with java

• eclipse -> new -> file -> gradle project

  
  

• structure of gradle project
  
  

• example source code

  package com.tomgregory.languageapp;
  
   import java.io.BufferedReader;
   import java.io.IOException;
   import java.io.InputStream;
   import java.io.InputStreamReader;
   import java.nio.charset.StandardCharsets;
  
   public class SayHello {
     public static void main(String[] args) throws IOException {
       String language = args[0];
       
       InputStream resourceStream = SayHello.class.getClassLoader().getResourceAsStream(language + ".txt");
       assert resourceStream != null;
       BufferedReader bufferedInputStream = new BufferedReader(new InputStreamReader(resourceStream, StandardCharsets.UTF_8));
       
       System.out.println(bufferedInputStream.readLine());
     }
     
   }

• cd to project folder

    C:\workspace\scheduler\get-going-with-gradle

• show gradlew tasks

      gradlew tasks
      gradlew tasks --all

• compileing java project

      gradlew compileJava

• build resources files

     gradlew processResources

• make jar acheive

    gradlew jar

• cd to jar path

    cd C:\workspace\scheduler\get-going-with-gradle\lib\build\libs

• run jar

    java -jar lib.jar en
    java -jar lib.jar es

example gradle test in java

• gradle make easy to test

• cd to project path

    cd C:\workspace\scheduler\get-going-with-gradle

• start test

    gradlew test

groovy essentials for gradle

1. you can write java in groovy

• groovy is a scripting language running in the JVM
• groovy extends java, making development quicker
• gradle uses groovy language features in build.gradle
• BUT can write Java code in Groovy(and build.gradle)

2. brackets are optional

• if the function has one more more argument

• println 'Bracket-free' same as println('Bracket-free')

• Gradle build script makes use of the Groovy feature

      dependencies {
          testImplementation 'org.junit.jupiter:junit-jupiter:5.6.3'
      }

• it's same to this

    void dependencies(Closure var1);

• and this

    dependencies ({
      testImplementation 'org.junit.jupiter:junit-jupiter:5.6.3'
    })

• dependencies is method

3. supports closures

• function as a variable

  def amazingCalculator = {a, b -> a + b }
  println amazingCalculator(2, 3) // print5

the task graph

• tasks can depend other tasks
  
  
• build aggregates assemble and check tasks
• you only need remember to run a single task, build

1. java plugin task graph

• it's just like tree graph
  
  
• can choose specific task to save time
  • check(just need to test project)
  • assemble(just need to build project)
• example

gradlew clean 
gradlew assemble
gradlew check
gradlew clean
gradlew build