Maven直接依赖、间接依赖、依赖冲突、依赖仲裁的实现

<!-- 这个 B 的依赖信息就是先声明的，所以仲裁后会留下B模块中依赖的C模块 -->
<dependency>
    <groupId>B</groupId>
    <artifactId>B</artifactId>
    <version>release</version>
</dependency>
<dependency>
    <groupId>D</groupId>
    <artifactId>D</artifactId>
    <version>release</version>
</dependency>

<!--在依赖列表的最前面主动声明模块C2.0的依赖信息-->
<dependency>
    <groupId>C</groupId>
    <artifactId>C</artifactId>
    <version>2.0</version>
</dependency>
<dependency>
    <groupId>B</groupId>
    <artifactId>B</artifactId>
    <version>release</version>
</dependency>
<dependency>
    <groupId>D</groupId>
    <artifactId>D</artifactId>
    <version>release</version>
</dependency>

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-enforcer-plugin</artifactId>
            <version>1.4.1</version>
            <executions>
                <execution>
                    <id>enforce-dependencies</id>
                    <phase>validate</phase>
                    <goals>
                        <goal>display-info</goal>
                        <goal>enforce</goal>
                    </goals>
                </execution>
            </executions>
            <dependencies>
                <dependency>
                    <groupId>org.codehaus.mojo</groupId>
                    <artifactId>extra-enforcer-rules</artifactId>
                    <version>1.0-beta-4</version>
                </dependency>
            </dependencies>
            <configuration>
                <rules>
                    <banDuplicateClasses>
                        <findAllDuplicates>true</findAllDuplicates>
                    </banDuplicateClasses>
                </rules>
            </configuration>
        </plugin>
    </plugins>
</build>

<dependency>
    <groupId></groupId>
    <artifactId></artifactId>
    <version></version>
    <!-- 排除依赖传递 -->
    <exclusions>
        <exclusion>
            <groupId>要弃用的模块的groupId</groupId>
            <artifactId>要弃用的模块的artifactId</artifactId>
        </exclusion>
    </exclusions>
</dependency>