Gradle 15 minute introductory tutorial

Hello everyone , I meet you again , I'm your friend, Quan Jun .

1-Gradle Introduction

Before reading or practicing the examples in this article , You must first ensure that Gradle Plug in installed to Eclipse in . without , You can view it by clicking on the link below Gradle Installation instructions ： – http://www.yiibai.com/gradle/how-install-gradle-windows.html

Objectives of this tutorial ：

This is the code structure diagram after the project is completed ：

2- establish Gradle project

open Eclipse, Click and select menu File->New->Other And select Gradle Project As shown in the figure below –

Click next （Next) Show some descriptions of the integration , as follows –

Click next （Next), And fill in the name of the project to be created HelloGradle And click Finish （Finish), as follows –

On the first run ,Eclipse Will download Gradle Relevant software or requirements specify local installation Gradle The path of . Please refer to Eclipse+Gradle Integration tutorial .

By default ,Gradle The software will pass Eclipse Download to C:/Users/{username}/.gradle. However, the configuration can be changed to other locations , This configuration is described in the last appendix of this guide .

Gradle The file structure required by the project will be automatically created . Its structure is similar to Maven project .

Be careful , This is a gradle Project defined project structure , What about? , Is it a little familiar with ？ – src/main/java – The folder contains all java Source file . – src/test/java – The folder contains all java The test case . – build.gradle – This file contains the scripts used to build the project . – settings.gradle – The file will contain the necessary settings , for example , Lazy relationship between tasks or projects, etc .

3- To configure Gradle

build.gradle File is the file that configures the library to be used in the project . It and Maven In the project pom.xml identical . open build.gradle File configuration library to be used , The code generated by default is as follows ：

/*
 * This build file was auto generated by running the Gradle 'init' task
 * by 'Administrator' at '16-10-30  Afternoon 4:20' with Gradle 3.1
 *
 * This generated file contains a sample Java project to get you started.
 * For more details take a look at the Java Quickstart chapter in the Gradle
 * user guide available at https://docs.gradle.org/3.1/userguide/tutorial_java_projects.html
 */

// Apply the java plugin to add support for Java
apply plugin: 'java'

// In this section you declare where to find the dependencies of your project
repositories {
    // Use 'jcenter' for resolving your dependencies.
    // You can declare any Maven/Ivy/file repository here.
    jcenter()
}

// In this section you declare the dependencies for your production and test code
dependencies {
    // The production code uses the SLF4J logging API at compile time
    compile 'org.slf4j:slf4j-api:1.7.21'

    // Declare the dependency for your favourite test framework you want to use in your tests.
    // TestNG is also supported by the Gradle Test task. Just change the
    // testCompile dependency to testCompile 'org.testng:testng:6.8.1' and add
    // 'test.useTestNG()' to your build script.
    testCompile 'junit:junit:4.12'
}

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Add the following code to the above source code file –

// https://mvnrepository.com/artifact/org.apache.commons/commons-lang3

compile group: 'org.apache.commons', name: 'commons-lang3', version: '3.0'

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Add the following –

Be careful ： If build.gradle File update ,Eclipse At present, the classpath will not be automatically updated . In the project or in build.gradle Right click in the file and select Gradle/Refresh Gradle To update the project .

If you add a new library to build.gradle In a statement ,Gradle They will be downloaded to the local computer .

Next , To create some Java Class to test using the downloaded class library , Here you create a simple CheckNumeric.java class , As shown below –

CheckNumeric.java The code for the class is as follows –

package com.yiibai.hellogradle;

import org.apache.commons.lang3.StringUtils;

public class CheckNumeric { 
   

    public static void main(String[] args) {
        String text1 = "a12340";
        String text2 = "1234";

        boolean result1 = StringUtils.isNumeric(text1);
        boolean result2 = StringUtils.isNumeric(text2);

        System.out.println(text1 + " is a numeric? " + result1);
        System.out.println(text2 + " is a numeric? " + result2);

    }

}

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function CheckNumeric Class should get the following results ：

You can clearly see the libraries used in the project , Its location on the hard disk is shown in the figure below –

4- explain Gradle How it works

In the above steps, we have created the project , And successfully run . Used by the project StringUtils class , It's a Apache class , Not in JDK Classes in the standard library . Traditionally , You must copy this class library to the project and declare the classpath . however , There is no need to copy and declare the classpath in the traditional way . These class libraries allow Gradle To manage . Now let's see Gradle How it works , This is shown in the following figure –

The figure above shows Gradle The whole process of work , Let's explain step by step . – stay build.gradle It is stated in that the project depends on common-lang3 Library version 3.0. – When using Gradle When the tool refreshes the project ,Gradle It will check whether the specified dependent library has a local repository on the computer . without ,Gradle Download from the Internet repository to the local . – Last ,Gradle Will automatically declare Classpath.

So all you need to do is build.gradle The file declares all the libraries you want to use , These libraries are provided by Gradle Manage yourself .

5- View the local repository

Will you have such a problem ： Where is the local repository on my computer ？ If you create a project according to all the above routines , Then look at the figure below –

And the above configuration used commons-lang3 The path of the library is C:\Users\Administrator\.gradle\caches\modules-2\files-2.1\org.apache.commons, As shown in the figure below –

6- Gradle Location configuration

By default ,Gradle The software will pass Eclipse Download to C:/Users/{username}/.gradle Directory . But you can change the configuration to its location . For example, you want to change the download directory to D:\worksp\gradle\Downloads, Then you can configure it according to the following operations .

stay Eclipse The menu , open Window -> References Choose a directory D:\worksp\gradle\Downloads, As shown in the figure below –

Right click on the item , And then choose Gradle -> Refresh Gradle Project,Gradle Will be downloaded to the new folder just set . As shown in the figure below –

7- Check on the network Gradle The repository

problem ： Where to find information groupId,artifactId And version ？ You can go to the website ： http://mvnrepository.com , For example, in our example above common-lang3 , Open... Can be found by searching in the website URL：http://mvnrepository.com/artifact/org.apache.commons/commons-lang3 This is shown in the following figure –

According to the version you want , find gradle Information about , As shown below –

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