Maven Made Simple: Membina Projek Java dengan Mudah

Panduan yang mudah diikuti untuk mengautomasikan binaan dengan Maven

Maven ialah alat penting untuk pembangun Java, memudahkan binaan projek, pengurusan pergantungan dan kawalan versi. Sama ada anda baru menggunakan Java atau pembangun yang berpengalaman, memahami Maven boleh meningkatkan aliran kerja anda dengan ketara. Dalam artikel ini, kami akan meneroka cara Maven berfungsi, ciri terasnya dan sebab ia merupakan penyelesaian terbaik untuk mengurus projek Java yang kompleks. Daripada mengautomasikan tugasan berulang hingga memastikan projek anda kekal teratur, Maven menjadikan pembangunan lebih lancar dan lebih cekap. Pada akhirnya, anda akan mempunyai pemahaman yang jelas tentang cara mengintegrasikan Maven ke dalam projek anda untuk binaan yang lebih pantas dan lebih dipercayai.

Maven bukan hanya tentang mengurus kebergantungan; ia juga mengenai memperkemas keseluruhan proses pembangunan. Ia mengikut struktur yang ringkas tetapi berkuasa, menggunakan fail "pom.xml" untuk menentukan kebergantungan projek, membina konfigurasi dan pemalam. Pendekatan ini memastikan projek anda kekal konsisten merentas persekitaran yang berbeza, menjadikannya mudah untuk bekerjasama dengan pasukan. Selain itu, fasa kitaran hayat Maven mengautomasikan tugas seperti penyusunan, ujian dan pembungkusan, supaya anda boleh lebih fokus pada menulis kod. Dengan menguasai Maven, anda bukan sahaja akan meningkatkan kecekapan binaan anda tetapi juga meningkatkan kualiti keseluruhan dan kebolehskalaan aplikasi Java anda. Mari selami lebih mendalam tentang faedah Maven!

Bina alatan

Alat binaan adalah penting untuk mengautomasikan proses membina aplikasi. Daripada menyusun kod secara manual, memuat turun kebergantungan, menjalankan ujian dan membungkus aplikasi, bina alat mengendalikan tugas ini secara automatik. Mereka memperkemas pembangunan dan memastikan konsistensi.

Berikut ialah perkara yang biasa dilakukan oleh alat binaan:

• Kompilkan kod sumber ke dalam bentuk boleh laku.
• Muat turun kebergantungan yang diperlukan seperti Spring Boot, Hibernate, JUnit, dll.
• Jalankan ujian unit untuk memastikan kod berfungsi seperti yang diharapkan.
• Bungkus aplikasi ke dalam fail JAR (untuk apl kendiri) atau WAR (untuk apl web).

Alat binaan popular untuk Java termasuk

• Semut
• Maven
• Gradle

"Sebagai pembangun Java, saya menggunakan Maven untuk pengurusan projek yang cekap, mengautomasikan binaan dan mengendalikan kebergantungan, memastikan proses pembangunan dan penghantaran yang diperkemas."

Maven

Maven ialah alat binaan sumber terbuka percuma, yang mengautomasikan proses binaan pembangunan aplikasi. ia diberikan oleh Apache Organization. Ia adalah perisian yang dibangunkan menggunakan bahasa pengaturcaraan java. dengan bantuan maven kami boleh mencipta struktur folder projek, apabila kami membangunkan projek itu begitu banyak perpustakaan dan rangka kerja yang kami perlukan untuk projek menambahnya secara manual ia adalah sukar dan mengambil masa bekerja untuk pembangun java. bahawa perpustakaan dan rangka kerja dipanggil kebergantungan projek, kebergantungan adalah seperti (cth: Spring-Boot, Hibernate, Kafaka, e-mel dll). Daripada kami memuat turun kebergantungan, kami boleh memberitahu kepada maven s/w untuk memuat turun kebergantungan. juga pandai Menyusun kod sumber, melaksanakan kes ujian untuk menguji kefungsian API, dan membungkus aplikasi sebagai jar(Java Archieve) / war(Web Archieve).

Untuk bermula dengan Maven, proses pemasangan melibatkan memuat turun pakej binari daripada tapak web rasmi Maven, menyediakan pembolehubah persekitaran untuk MAVEN_HOME dan mengesahkan pemasangan melalui terminal atau command prompt dengan menjalankan mvn -versi.

Pemasangan Maven pada Windows

Langkah 1: Muat turun Maven Untuk bermula

muat turun Maven dari tapak web rasmi: Pergi ke Halaman Muat Turun Maven. Muat turun arkib zip binari untuk versi terkini Maven.

Langkah 2: Ekstrak Maven

Setelah dimuat turun: Ekstrak fail ZIP yang dimuat turun ke folder. Sebagai contoh, anda boleh menggunakan C:Program FilesApachemaven atau lokasi lain pilihan anda.

Langkah 3: Tetapkan Pembolehubah Persekitaran

Untuk memastikan Maven tersedia daripada baris arahan, anda perlu menyediakan pembolehubah persekitaran. Klik kanan PC ini dan pilih Properties

Klik Tetapan Sistem Terperinci → Pembolehubah Persekitaran.

Dalam Pembolehubah Sistem, klik Baharu dan tambah:
Nama pembolehubah: MAVEN_HOME

Nilai boleh ubah

C:\Program Files\Apache\maven

(atau direktori tempat anda mengekstrak Maven).
Seterusnya, cari pembolehubah Laluan dalam Pembolehubah Sistem, pilihnya dan klik Edit.

Add a new entry: %MAVEN_HOME%\bin.

Langkah 4: Sahkan Pemasangan

To check if Maven is installed correctly, open a command prompt and run the following command:

mvn -version

Maven Terminology

Archetype

An Archetype is a template that helps you quickly create a Maven project with a predefined structure. It defines the directory layout and initial configuration files to simplify project setup.

groupId

The groupId identifies the organization or project to which a Maven artifact belongs. It follows a reverse domain name convention (e.g., com.example.project) and ensures that dependencies are uniquely identifiable across the system.

artifactId

The artifactId is the name of the project or library. It's used along with the groupId and version to uniquely identify a specific project artifact, such as a JAR, WAR, or other packages.

packaging

The packaging type defines the build output type for your Maven project. Common options include jar, war, or pom. It determines how Maven will package the code, usually as a JAR or WAR file.

version

The version specifies the release or iteration of a Maven project. It's crucial for managing different versions of a library or artifact, allowing you to reference a specific version when adding dependencies to other projects.

SNAPSHOT : Under development
RELEASE : Development completed

Creating a Stand-Alone Application Using Maven With CMD

Maven is an excellent tool for building and managing Java projects, especially when it comes to creating stand-alone applications. Let’s walk through the steps of setting up a basic stand-alone Java application using Maven.

mvn archetype:generate -DgroupId=com.example.app -DartifactId=standalone-app -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false

• groupId: Uniquely identifies the project’s group.
• artifactId: The name of your application.
• archetypeArtifactId: Specifies the archetype for a simple Java project.

Once project created then verify project folder structure

standalone-app
│
├── src
│   ├── main
│   │   └── java               # Application source code (.java files)
│   │
│   ├── test
│   │   └── java               # Application Unit Test code (.java files)
│
└── pom.xml                    # Project Object Model (Maven configuration file)

src/main/java is containing the application source code.
src/test/java is containing the application test source code.
pom.xml file containing the maven configurations.

POM.XML

The pom.xml file, which stands for Project Object Model, is a crucial component of any Maven project. It is automatically generated when you create a Maven project and serves as the input file for Maven software. The pom.xml file defines the project’s metadata, including its name, version, and dependencies on various frameworks such as Spring, Hibernate, Kafka, and more. Instead of manually downloading these dependencies, you can specify them in the pom.xml file, and Maven will automatically fetch them for you. This makes managing project dependencies efficient and organized, allowing developers to focus on writing code without worrying about handling each library individually. Essentially, the pom.xml acts as a roadmap for Maven, guiding it on how to build and manage your Java project.

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example.app</groupId>
    <artifactId>standalone-app</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>  <!-- Java version -->
        <maven.compiler.target>17</maven.compiler.target>
    </properties>

    <dependencies>
        <!-- JUnit for unit testing -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.2</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <!-- Maven Compiler Plugin -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>${maven.compiler.source}</source>
                    <target>${maven.compiler.target}</target>
                </configuration>
            </plugin>

            <!-- Maven Shade Plugin for creating an executable JAR -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>3.2.4</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <transformers>
                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <mainClass>com.example.app.App</mainClass>  <!-- Main class -->
                                </transformer>
                            </transformers>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

Maven Goals

Maven goals represent specific tasks that can be executed during the build lifecycle of a Maven project. Each goal corresponds to a distinct action, such as compiling code, running tests, packaging artifacts, or deploying to a repository.

By invoking these goals, developers can automate and streamline their build processes, ensuring that projects are built consistently and efficiently. Each goal can be run individually or as part of a larger lifecycle phase, providing flexibility in project management.

clean: Deletes the target directory, which contains compiled code and packaged artifacts, ensuring a fresh build.

compile: Compiles the source code of the project, producing class files from Java source files in the src/main/java directory.

test: Runs the unit tests defined in the src/test/java directory using a testing framework like JUnit.

package: Packages the compiled code into a distributable format, such as a JAR or WAR file, based on the project configuration in pom.xml.

install: Installs the packaged JAR/WAR file into the local Maven repository, making it available for other projects on the same machine.

deploy: Copies the packaged JAR/WAR file to a remote repository, making it available for other developers and projects.

site: Generates a site for the project, including documentation, reports, and project information, typically found in the target/site directory.

validate: Validates the project’s configuration and verifies that all required information is available before the build begins.

verify: Runs any checks to ensure the package is valid and meets quality standards, executing any verification tasks defined in the project.

archetype: Creates a new Maven project based on a specified archetype, setting up a project structure and initial files.

These goals can be executed from the command line, allowing developers to manage the build lifecycle effectively. You can run a specific goal using the following command format:

mvn [Goal]

Maven Repository

Maven repositories store project artifacts like libraries an dependencies. There are three main types of Maven repositories

Local Repository
Stores artifacts on your machine for quick access. it is a oyr system specific.

Remote Repository
Hosts artifacts on a server, accessible over the network. it is a organization specific.

Central Repository
Default public repository for widely used open-source libraries. it is accessed by everyone.

When you create a project and build it using Maven, it first checks your local repository (typically located at ~/.m2/repository) for any dependencies the project needs. If it finds the required dependencies in the local repository, Maven uses them directly, without downloading them again.

If the dependencies aren't available locally, Maven fetches them from a remote repository, such as Maven Central or another configured repository. Once downloaded, the dependencies are stored in the local repository for future use, so they don't need to be re-downloaded. This process helps optimize resource use and speeds up the build by preventing unnecessary downloads.

Maven build lifecycle

The Maven build lifecycle is a series of phases that automate the process of building and managing Java projects. It consists of three main lifecycles: default, clean, and site. The default lifecycle is the most commonly used, handling tasks like validating the project structure, compiling the code, running tests, packaging the output (e.g., into a JAR or WAR), and deploying the package to a remote repository. The clean lifecycle is responsible for cleaning up the project by deleting generated files from previous builds, while the site lifecycle is used to generate project documentation and reports. Each lifecycle consists of specific phases that are executed in sequence, ensuring that Maven handles everything from code compilation to deployment in a structured, automated way.

Conclusion

Maven has revolutionized how Java projects are built and managed, offering developers an efficient and automated approach to handling essential project tasks. Its core strength lies in dependency management, where Maven checks for required libraries in the local repository and fetches them from remote repositories like Maven Central if they're not available. This saves time and eliminates the need for manual dependency tracking, ensuring that projects always have the correct versions of required libraries.

The declarative nature of Maven, governed by the pom.xml file, standardizes the build process, making it easier to maintain consistency across different development environments. Whether it’s compiling code, running tests, or packaging the project for deployment, Maven's build lifecycle manages these steps seamlessly.

Additionally, Maven’s plugin system enhances its flexibility, enabling developers to integrate a wide array of tools and functionalities. Plugins for running tests, generating documentation, deploying artifacts, and more extend Maven’s utility far beyond a basic build tool.

By automating repetitive tasks and streamlining complex project setups, Maven allows developers to focus on writing code, improving productivity, and reducing potential errors. Its widespread adoption within the Java ecosystem makes it an indispensable tool for building modern, scalable, and maintainable Java applications.

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