Java在运行时获得maven依赖项版本

Question

是否可能在运行时检索特定maven依赖项的版本？

例如。对于pom.xml：

<dependency>
    <groupId>foo.bar</groupId>
    <artifactId>foobar</artifactId>
    <version>1.0</version>
</dependency>

我想检索具有工件IDfoobar的特定依赖项的版本1.0。

Answer 1

pom.xml

<?xml version="1.0" encoding="UTF-8"?>

<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>org.example</groupId>
    <artifactId>WDProject</artifactId>
    <version>1.0-SNAPSHOT</version>

    <name>WDProject</name>
    <url>http://www.nosite.com</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.7</maven.compiler.source>
        <maven.compiler.target>1.7</maven.compiler.target>

        <selenium.version>3.141.59</selenium.version>
        <webdrivermanager.version>3.7.1</webdrivermanager.version>

    </properties>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>

        <!-- https://mvnrepository.com/artifact/io.github.bonigarcia/webdrivermanager -->
        <dependency>
            <groupId>io.github.bonigarcia</groupId>
            <artifactId>webdrivermanager</artifactId>
            <version>${webdrivermanager.version}</version>
        </dependency>

        <dependency>
            <groupId>org.seleniumhq.selenium</groupId>
            <artifactId>selenium-api</artifactId>
            <version>${selenium.version}</version>
        </dependency>
        <dependency>
            <groupId>org.seleniumhq.selenium</groupId>
            <artifactId>selenium-server</artifactId>
            <version>${selenium.version}</version>
        </dependency>
        <dependency>
            <groupId>org.seleniumhq.selenium</groupId>
            <artifactId>selenium-remote-driver</artifactId>
            <version>${selenium.version}</version>
        </dependency>
        <dependency>
            <groupId>org.seleniumhq.selenium</groupId>
            <artifactId>selenium-java</artifactId>
            <version>${selenium.version}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>net.lingala.zip4j</groupId>
            <artifactId>zip4j</artifactId>
            <version>2.2.4</version>
        </dependency>
        <dependency>
            <groupId>org.apache.maven</groupId>
            <artifactId>maven-model</artifactId>
            <version>3.3.9</version>
        </dependency>
    </dependencies>

    <build>
        <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
            <plugins>
                <!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
                <plugin>
                    <artifactId>maven-clean-plugin</artifactId>
                    <version>3.1.0</version>
                </plugin>
                <!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
                <plugin>
                    <artifactId>maven-resources-plugin</artifactId>
                    <version>3.0.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.8.0</version>
                </plugin>
                <plugin>
                    <artifactId>maven-surefire-plugin</artifactId>
                    <version>2.22.1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-jar-plugin</artifactId>
                    <version>3.0.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-install-plugin</artifactId>
                    <version>2.5.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-deploy-plugin</artifactId>
                    <version>2.8.2</version>
                </plugin>
                <!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
                <plugin>
                    <artifactId>maven-site-plugin</artifactId>
                    <version>3.7.1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-project-info-reports-plugin</artifactId>
                    <version>3.0.0</version>
                </plugin>
            </plugins>
        </pluginManagement>
    </build>
</project>

虽然您想要的是搜索特定的依赖项，但下面的代码检索了pom文件中可用的依赖项的所有详细信息。您只需要创建一个包装器方法来检索特定依赖项的详细信息。

import org.apache.maven.model.Model;
import org.apache.maven.model.io.xpp3.MavenXpp3Reader;
import org.codehaus.plexus.util.xml.pull.XmlPullParserException;

import java.io.FileReader;
import java.io.IOException;


class SampleMavenDependencyReader {

    public static void main(String[] args) throws IOException, XmlPullParserException {
        MavenXpp3Reader reader = new MavenXpp3Reader();
        Model model = reader.read(new FileReader("/Users/nonadmin/bins/projects/IdeaProjects/WDProject/pom.xml"));

        for (int i = 0; i < model.getDependencies().size(); i++) {
            System.out.println(model.getDependencies().get(i));
        }
    }
}

输出

Dependency {groupId=junit, artifactId=junit, version=4.11, type=jar}
Dependency {groupId=io.github.bonigarcia, artifactId=webdrivermanager, version=${webdrivermanager.version}, type=jar}
Dependency {groupId=org.seleniumhq.selenium, artifactId=selenium-api, version=${selenium.version}, type=jar}
Dependency {groupId=org.seleniumhq.selenium, artifactId=selenium-server, version=${selenium.version}, type=jar}
Dependency {groupId=org.seleniumhq.selenium, artifactId=selenium-remote-driver, version=${selenium.version}, type=jar}
Dependency {groupId=org.seleniumhq.selenium, artifactId=selenium-java, version=${selenium.version}, type=jar}
Dependency {groupId=net.lingala.zip4j, artifactId=zip4j, version=2.2.4, type=jar}
Dependency {groupId=org.apache.maven, artifactId=maven-model, version=3.3.9, type=jar}~~~

Answer 2

这里最有问题的部分是根据罐子的名字找到一个罐子。不幸的是，这在Java没有100%可靠的方法。要按名称获取JAR，您需要扫描正在运行的应用程序的类路径，该类路径可能并不总是存在（例如，因为使用了自定义类加载器，或者使用了模块路径而不是类路径）。

但是，让我们假设您没有使用诸如自定义类加载器之类的任何华丽特性，并且您得到了包含所有Maven依赖项的类路径。你现在需要做什么？我试着描述一个粗略的算法：

• 从类路径检索所有JAR文件的路径。
• 扫描每个JAR文件并找到文件pom.properties。它位于meta-inf/maven/{groupId}/{artifactId}中。
• 在pom.properties中查找version属性的值。

同样，这个解决方案也不会完全可靠。您必须决定：您是否真的需要版本信息，以及出于什么目的？