如何阻止maven-shade-plugin阻止opensaml-impl類型的java.util.ServiceLoader初始化

Question

使用OpenSAML 3時，必須首先使用以下代碼行從opensaml-saml-impl工件加載組件：

InitializationService.initialize();

這使用java.util.ServiceLoader來加載任何實現Initializer類型 。

當我編寫測試並使用mvn integration-test運行它時，這很好用，我可以看到所有內容都已加載：

Assert.assertTrue(
    XMLObjectProviderRegistrySupport
        .getUnmarshallerFactory()
        .getUnmarshallers()
        .size() > 400);

但是，我的項目使用maven-shade-plugin 。 如果我將代碼打包到超級jar中，則上述條件不正確：

mvn package
java -jar /path/to/my.jar

在這種情況下，我觀察到只有9 unmarshallers已加載（在那些opensaml-core ，而不是那些在opensaml-saml-impl 。然而，當我觀看的輸出mvn package ，我可以看到，類型都包含在陰影罐：

[INFO] Including org.opensaml:opensaml-saml-impl:jar:3.2.0 in the shaded jar.
[INFO] Including org.opensaml:opensaml-profile-api:jar:3.2.0 in the shaded jar.
[INFO] Including org.opensaml:opensaml-messaging-api:jar:3.2.0 in the shaded jar.
[INFO] Including org.opensaml:opensaml-saml-api:jar:3.2.0 in the shaded jar.
[INFO] Including org.opensaml:opensaml-xmlsec-api:jar:3.2.0 in the shaded jar.
[INFO] Including org.opensaml:opensaml-soap-api:jar:3.2.0 in the shaded jar.
[INFO] Including org.opensaml:opensaml-storage-api:jar:3.2.0 in the shaded jar.
[INFO] Including org.opensaml:opensaml-security-impl:jar:3.2.0 in the shaded jar.
[INFO] Including org.opensaml:opensaml-security-api:jar:3.2.0 in the shaded jar.

我可以使用以下啞代碼解決此問題：

private static void initManuallyInsteadOfWithInitializationServiceSoThatMavenShadePluginDoesNotRemoveThem() throws InitializationException {
    new ApacheXMLSecurityInitializer().init();
    new ClientTLSValidationConfiguratonInitializer().init();
    new GlobalAlgorithmRegistryInitializer().init();
    new GlobalParserPoolInitializer().init();
    new GlobalSecurityConfigurationInitializer().init();
    new JavaCryptoValidationInitializer().init();
    new SAMLConfigurationInitializer().init();
    new org.opensaml.core.xml.config.XMLObjectProviderInitializer().init();
    new org.opensaml.xmlsec.config.XMLObjectProviderInitializer().init();
    new XMLObjectProviderInitializer().init();
}

這完全違背了插件系統的要點，但它確實允許我的程序運行。

作為參考，這是pom.xml的相關位：

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-shade-plugin</artifactId>
    <version>2.3</version>
    <executions>
        <execution>
            <phase>package</phase>
            <goals>
                <goal>shade</goal>
            </goals>
            <configuration>
                <transformers>
                    <transformer
                            implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                        <manifestEntries>
                            <Main-Class>com.example.Server</Main-Class>
                        </manifestEntries>
                    </transformer>
                    <transformer
                            implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
                        <resource>META-INF/services/io.vertx.core.spi.VerticleFactory</resource>
                    </transformer>
                </transformers>
                <artifactSet>
                </artifactSet>
                <outputFile>${project.build.directory}/${project.artifactId}-${project.version}-fat.jar
                </outputFile>
                <filters>
                    <filter>
                        <!-- Fix java.lang.SecurityException: Invalid signature file digest for Manifest main attributes
                             when server starts inside Docker container due to inclusion of OpenSAML and use of
                             uber-jar / maven-shade-plugin. See http://stackoverflow.com/a/6743609 -->
                        <artifact>*:*</artifact>
                        <excludes>
                            <exclude>META-INF/*.SF</exclude>
                            <exclude>META-INF/*.DSA</exclude>
                            <exclude>META-INF/*.RSA</exclude>
                        </excludes>
                    </filter>
                    <filter>
                        <!-- This was one of my attempts to fix the problem.
                             Unfortunately, it doesn't work. -->
                        <artifact>org.opensaml:opensaml-saml-impl</artifact>
                        <includes>
                            <include>**</include>
                        </includes>
                    </filter>
                </filters>
            </configuration>
        </execution>
    </executions>
</plugin>

Answer 1

當您使用ServiceLoader API將Maven Shade插件與依賴項一起使用時，您應該使用ServicesResourceTransformer ，它專用於將文件合並在一起。 如果插件重定位類 ，它還將正確地重新定位每個服務文件中的類名，這與AppendingTransformer不同。

因此，您只需將當前的AppendingTransformer替換為

<transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>

它將確保合並您的依賴項的META-INF/services下的每個服務文件，而無需全部聲明它們。