I know that @Parameter can be used directly in mojo, and I know that the documentation of @Parameter says

Beans injected into Mojo parameters are prepared by Sisu JSR330-based container: this annotation is only effective on fields of the Mojo class itself, nested bean injection requires Sisu or JSR330 annotations.

I tried the following methods (see MyParam), but there are not woring:

/* MyParam */
@ToString
@Setter
@Getter
public class MyParam {
    // not working
    @Parameter(defaultValue = "${project.build.outputDirectory}")
    private String outputDir0;

    // not working
    @Inject
    @Parameter(defaultValue = "${project.build.outputDirectory}")
    private String outputDir1;

    // not working
    @Parameters
    @Parameter(defaultValue = "${project.build.outputDirectory}")
    private String outputDir2;
}

/* mojo */
@Getter
@Setter
@Mojo(name = "my-mojo", defaultPhase = LifecyclePhase.PROCESS_RESOURCES, threadSafe = true)
public class MyMojo extends AbstractMojo {
    @Parameter(required = true)
    private MyParam myParam;

    // working
    @Parameter(defaultValue = "${project.build.outputDirectory}", required = true)
    protected String outputDirectory;

    public void execute() throws MojoExecutionException {
        getLog().info(String.format("myParam: %s", myParam));
        getLog().info(String.format("outputDirectory: %s", outputDirectory));
    }
}

<!-- 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.xxx</groupId>
    <artifactId>my-mojo-maven-plugin</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>maven-plugin</packaging>

    <name>my-mojo-maven-plugin</name>
    <description>my-mojo-maven-plugin</description>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <javaVersion>8</javaVersion>
        <maven.compiler.source>${javaVersion}</maven.compiler.source>
        <maven.compiler.target>${javaVersion}</maven.compiler.target>

        <maven-plugin.version>3.8.1</maven-plugin.version>
        <maven-plugin-annotations.version>3.10.2</maven-plugin-annotations.version>
        
        <lombok.version>1.18.30</lombok.version>
        <junit.version>4.13.2</junit.version>
        <slf4j.version>2.0.13</slf4j.version>
    </properties>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.apache.maven</groupId>
                <artifactId>maven-plugin-api</artifactId>
                <version>${maven-plugin.version}</version>
            </dependency>
            <dependency>
                <groupId>org.apache.maven.plugin-tools</groupId>
                <artifactId>maven-plugin-annotations</artifactId>
                <version>${maven-plugin-annotations.version}</version>
            </dependency>
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>${junit.version}</version>
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>${lombok.version}</version>
            </dependency>
            <dependency>
                <groupId>org.slf4j</groupId>
                <artifactId>slf4j-simple</artifactId>
                <version>${slf4j.version}</version>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>org.apache.maven</groupId>
            <artifactId>maven-plugin-api</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.apache.maven.plugin-tools</groupId>
            <artifactId>maven-plugin-annotations</artifactId>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-plugin-plugin</artifactId>
                <version>3.10.2</version>
                <configuration>
                    <skipErrorNoDescriptorsFound>true</skipErrorNoDescriptorsFound>
                </configuration>
                <executions>
                    <execution>
                        <id>generate-helpgoal</id>
                        <goals>
                            <goal>helpmojo</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

<!-- using -->
<plugin>
    <groupId>com.xmcx</groupId>
    <artifactId>my-mojo-maven-plugin</artifactId>
    <version>1.0-SNAPSHOT</version>
    <executions>
        <execution>
            <phase>process-resources</phase>
            <goals>
                <goal>my-mojo</goal>
            </goals>
            <id>my-mojo</id>
            <configuration>
                <myParam>
                </myParam>
            </configuration>
        </execution>
    </executions>
</plugin>