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Maven可执行jar打包与使用Jackson的Maven exec无效

javajacksonmaven-3pom.xml
3
我需要一些帮助来尝试让一个可执行文件正常工作。这是一个棘手的问题，我已经缩小了范围，发现maven exec运行程序和maven shade插件或maven assembly插件打包文件的方式有所不同。
我正在使用Netty和JAX-RS构建一个Java REST服务，并使用Jackson将POJO转换为JSON。
当执行`mvn exec:java`或`java -jar`时，服务器能够正确启动。但是，当针对`java -jar`文件发出请求时，我会收到以下错误：
Could not find MessageBodyWriter for response object of type: [Ljava.lang.Object; of media type: application/json

看起来似乎某些东西没有被正确打包，但我不确定是什么。可能缺少传递依赖关系？

这是我的POM：

<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.test.myserver</groupId>
<artifactId>myserver</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>

<name>myserver</name>
<url>http://maven.apache.org</url>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>

<repositories>
    <repository>
        <id>oss-sonatype</id>
        <name>oss-sonatype</name>
        <url>https://oss.sonatype.org/content/repositories/snapshots/</url>
        <snapshots>
            <enabled>true</enabled>
        </snapshots>
    </repository>
</repositories>

<build>
    <plugins>
        <!-- For executing in maven itself (mvn exec:java) -->
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>exec-maven-plugin</artifactId>
            <version>1.2.1</version>
            <executions>
                <execution>
                    <goals>
                        <goal>java</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <mainClass>com.test.myserver.App</mainClass>
            </configuration>
        </plugin>
        <plugin>
            <!-- for packaging (mvn package) -->
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-shade-plugin</artifactId>
            <version>2.2</version>
            <executions>
                <execution>
                    <phase>package</phase>
                    <goals>
                        <goal>shade</goal>
                    </goals>
                    <configuration>
                        <transformers>
                            <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                <mainClass>com.test.myserver.App</mainClass>
                            </transformer>
                        </transformers>
                    </configuration>
                </execution>
            </executions>
        </plugin>
        <!-- The configuration of maven-assembly-plugin -->
        <plugin>
            <!-- for packaging (mvn compile assembly:single) -->
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-assembly-plugin</artifactId>
            <version>2.4</version>
            <!-- The configuration of the plugin -->
            <configuration>
                <archive>
                    <manifest>
                        <mainClass>com.test.myserver.App</mainClass>
                    </manifest>
                </archive>
                <descriptorRefs>
                    <descriptorRef>jar-with-dependencies</descriptorRef>
                </descriptorRefs>
            </configuration>
        </plugin>
    </plugins>
</build>

<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>LATEST</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>com.googlecode.plist</groupId>
        <artifactId>dd-plist</artifactId>
        <version>LATEST</version>
    </dependency>

    <!-- MongoDB -->
    <dependency>
        <groupId>org.mongodb</groupId>
        <artifactId>mongo-java-driver</artifactId>
        <version>2.12.0</version>
    </dependency>
    <dependency>
        <groupId>org.mongojack</groupId>
        <artifactId>mongojack</artifactId>
        <version>2.1.0-SNAPSHOT</version>
    </dependency>

    <!-- REST Server -->
    <dependency>
        <groupId>org.jboss.resteasy</groupId>
        <artifactId>resteasy-jaxrs</artifactId>
        <version>LATEST</version>
    </dependency>
    <dependency>
        <groupId>org.jboss.resteasy</groupId>
        <artifactId>resteasy-netty</artifactId>
        <version>LATEST</version>
    </dependency>
    <dependency>
        <groupId>org.jboss.resteasy</groupId>
        <artifactId>resteasy-jackson2-provider</artifactId>
        <version>LATEST</version>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>LATEST</version>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-simple</artifactId>
        <version>LATEST</version>
    </dependency>
    <dependency>
        <groupId>org.reflections</groupId>
        <artifactId>reflections</artifactId>
        <version>LATEST</version>
    </dependency>
</dependencies>

Maven shade使用mvn package命令执行。 Maven assembly使用mvn compile assembly:single命令执行。

谢谢！

编辑

我对比了mvn shade的输出和mvn dependency:tree的输出，它们在本质上看起来是相同的。

依赖树输出结果

$ mvn dependency:tree
[INFO] Scanning for projects...
[INFO]
[INFO] Using the builder org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder with a thread count of 1
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building myserver 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-dependency-plugin:2.8:tree (default-cli) @ myserver ---
[INFO] com.test.myserver:myserver:jar:1.0-SNAPSHOT
[INFO] +- junit:junit:jar:4.11:test
[INFO] |  \- org.hamcrest:hamcrest-core:jar:1.3:test
[INFO] +- com.googlecode.plist:dd-plist:jar:1.8:compile
[INFO] +- org.mongodb:mongo-java-driver:jar:2.12.0:compile
[INFO] +- org.mongojack:mongojack:jar:2.1.0-SNAPSHOT:compile
[INFO] |  +- com.fasterxml.jackson.core:jackson-databind:jar:2.2.3:compile
[INFO] |  +- de.undercouch:bson4jackson:jar:2.2.0:compile
[INFO] |  +- javax.persistence:persistence-api:jar:1.0.2:compile
[INFO] |  \- commons-io:commons-io:jar:2.4:compile
[INFO] +- org.jboss.resteasy:resteasy-jaxrs:jar:3.0.8.Final:compile
[INFO] |  +- org.jboss.resteasy:jaxrs-api:jar:3.0.8.Final:compile
[INFO] |  +- org.jboss.spec.javax.annotation:jboss-annotations-api_1.1_spec:jar:1.0.1.Final:compile
[INFO] |  +- javax.activation:activation:jar:1.1:compile
[INFO] |  +- org.apache.httpcomponents:httpclient:jar:4.2.1:compile
[INFO] |  |  +- org.apache.httpcomponents:httpcore:jar:4.2.1:compile
[INFO] |  |  +- commons-logging:commons-logging:jar:1.1.1:compile
[INFO] |  |  \- commons-codec:commons-codec:jar:1.6:compile
[INFO] |  \- net.jcip:jcip-annotations:jar:1.0:compile
[INFO] +- org.jboss.resteasy:resteasy-netty:jar:3.0.8.Final:compile
[INFO] |  \- io.netty:netty:jar:3.6.4.Final:compile
[INFO] +- org.jboss.resteasy:resteasy-jackson2-provider:jar:3.0.8.Final:compile
[INFO] |  +- com.fasterxml.jackson.core:jackson-core:jar:2.3.2:compile
[INFO] |  +- com.fasterxml.jackson.core:jackson-annotations:jar:2.3.2:compile
[INFO] |  \- com.fasterxml.jackson.jaxrs:jackson-jaxrs-json-provider:jar:2.3.2:compile
[INFO] |     +- com.fasterxml.jackson.jaxrs:jackson-jaxrs-base:jar:2.3.2:compile
[INFO] |     \- com.fasterxml.jackson.module:jackson-module-jaxb-annotations:jar:2.3.2:compile
[INFO] +- org.slf4j:slf4j-api:jar:1.7.7:compile
[INFO] +- org.slf4j:slf4j-simple:jar:1.7.7:compile
[INFO] \- org.reflections:reflections:jar:0.9.9-RC1:compile
[INFO]    +- com.google.guava:guava:jar:11.0.2:compile
[INFO]    |  \- com.google.code.findbugs:jsr305:jar:1.3.9:compile
[INFO]    +- org.javassist:javassist:jar:3.16.1-GA:compile
[INFO]    \- dom4j:dom4j:jar:1.6.1:compile
[INFO]       \- xml-apis:xml-apis:jar:1.0.b2:compile
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.999 s
[INFO] Finished at: 2014-04-22T17:09:47-08:00
[INFO] Final Memory: 13M/310M
[INFO] ------------------------------------------------------------------------

来自shade的输出

$ mvn package
[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ myserver ---
[INFO] Building jar: /myserver/target/myserver-1.0-SNAPSHOT.jar
[INFO]
[INFO] --- maven-shade-plugin:2.2:shade (default) @ myserver ---
[INFO] Including com.googlecode.plist:dd-plist:jar:1.8 in the shaded jar.
[INFO] Including org.mongodb:mongo-java-driver:jar:2.12.0 in the shaded jar.
[INFO] Including org.mongojack:mongojack:jar:2.1.0-SNAPSHOT in the shaded jar.
[INFO] Including com.fasterxml.jackson.core:jackson-databind:jar:2.2.3 in the shaded jar.
[INFO] Including de.undercouch:bson4jackson:jar:2.2.0 in the shaded jar.
[INFO] Including javax.persistence:persistence-api:jar:1.0.2 in the shaded jar.
[INFO] Including commons-io:commons-io:jar:2.4 in the shaded jar.
[INFO] Including org.jboss.resteasy:resteasy-jaxrs:jar:3.0.8.Final in the shaded jar.
[INFO] Including org.jboss.resteasy:jaxrs-api:jar:3.0.8.Final in the shaded jar.
[INFO] Including org.jboss.spec.javax.annotation:jboss-annotations-api_1.1_spec:jar:1.0.1.Final in the shaded jar.
[INFO] Including javax.activation:activation:jar:1.1 in the shaded jar.
[INFO] Including org.apache.httpcomponents:httpclient:jar:4.2.1 in the shaded jar.
[INFO] Including org.apache.httpcomponents:httpcore:jar:4.2.1 in the shaded jar.
[INFO] Including commons-logging:commons-logging:jar:1.1.1 in the shaded jar.
[INFO] Including commons-codec:commons-codec:jar:1.6 in the shaded jar.
[INFO] Including net.jcip:jcip-annotations:jar:1.0 in the shaded jar.
[INFO] Including org.jboss.resteasy:resteasy-netty:jar:3.0.8.Final in the shaded jar.
[INFO] Including io.netty:netty:jar:3.6.4.Final in the shaded jar.
[INFO] Including org.jboss.resteasy:resteasy-jackson2-provider:jar:3.0.8.Final in the shaded jar.
[INFO] Including com.fasterxml.jackson.core:jackson-core:jar:2.3.2 in the shaded jar.
[INFO] Including com.fasterxml.jackson.core:jackson-annotations:jar:2.3.2 in the shaded jar.
[INFO] Including com.fasterxml.jackson.jaxrs:jackson-jaxrs-json-provider:jar:2.3.2 in the shaded jar.
[INFO] Including com.fasterxml.jackson.jaxrs:jackson-jaxrs-base:jar:2.3.2 in the shaded jar.
[INFO] Including com.fasterxml.jackson.module:jackson-module-jaxb-annotations:jar:2.3.2 in the shaded jar.
[INFO] Including org.slf4j:slf4j-api:jar:1.7.7 in the shaded jar.
[INFO] Including org.slf4j:slf4j-simple:jar:1.7.7 in the shaded jar.
[INFO] Including org.reflections:reflections:jar:0.9.9-RC1 in the shaded jar.
[INFO] Including com.google.guava:guava:jar:11.0.2 in the shaded jar.
[INFO] Including com.google.code.findbugs:jsr305:jar:1.3.9 in the shaded jar.
[INFO] Including org.javassist:javassist:jar:3.16.1-GA in the shaded jar.
[INFO] Including dom4j:dom4j:jar:1.6.1 in the shaded jar.
[INFO] Including xml-apis:xml-apis:jar:1.0.b2 in the shaded jar.
[INFO] Replacing original artifact with shaded artifact.
[INFO] Replacing /myserver/target/myserver-1.0-SNAPSHOT.jar with /myserver/target/myserver-1.0-SNAPSHOT-shaded.jar
[INFO] Dependency-reduced POM written at: /myserver/dependency-reduced-pom.xml
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 4.658 s
[INFO] Finished at: 2014-04-22T17:05:50-08:00
[INFO] Final Memory: 39M/310M
[INFO] ------------------------------------------------------------------------
2个回答
8
插件配置中缺少 服务转换器 ，该转换器合并了服务发现机制使用的META-INF/services文件。以下是一个示例：
<transformers>
    <transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer" />
    <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
        <mainClass>com.example.helloworld.HelloWorldApplication</mainClass>
    </transformer>
</transformers>
谢谢你发现了这个问题。问题已经解决了。 - mikeho
0

有趣的是，昨天我问了自己一个问题：“为什么我需要一个超级JAR文件？”结果证明，我不需要也不应该使用超级JAR文件。Alexey正确地回答了解决即时问题的问题，但我还想发布一种替代方案，以便稍微有所不同。

与其使用shade插件构建超级JAR文件，我决定创建一个标准JAR文件并导出运行我的应用程序所需的所有依赖项。这意味着我现在使用Maven Jar插件创建我的JAR文件和Maven Dependency插件导出库。以下是pom.xml的构建部分：

<build>
    <plugins>
        <!-- For copying the libraries to the output directory -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-dependency-plugin</artifactId>
            <version>2.8</version>
            <executions>
                <execution>
                    <id>copy-dependencies</id>
                    <phase>package</phase>
                    <goals>
                        <goal>copy-dependencies</goal>
                    </goals>
                    <configuration>
                        <outputDirectory>${project.build.directory}/lib</outputDirectory>
                        <overWriteReleases>false</overWriteReleases>
                        <overWriteSnapshots>false</overWriteSnapshots>
                        <overWriteIfNewer>true</overWriteIfNewer>
                    </configuration>
                </execution>
            </executions>
        </plugin>
        <!-- Create the executable jar -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-jar-plugin</artifactId>
            <version>2.4</version>
            <configuration>
                <archive>
                    <manifest>
                        <addClasspath>true</addClasspath>
                        <classpathPrefix>lib/</classpathPrefix>
                        <mainClass>com.test.myserver.App</mainClass>
                        <useUniqueVersions>false</useUniqueVersions>
                    </manifest>
                </archive>
            </configuration>
        </plugin>
    </plugins>
</build>

由于我的输出目录是target/，所以我的jar文件生成为target/myserver-1.0-SNAPSHOT.jar，所有依赖项都在target/lib/中。 maven-jar-plugin还会构建类路径并将其正确指向lib/目录，因此我几乎已经完成了。这也使得将来更容易替换单个库，而不是上传一个全新的jar文件。

从命令行中构建jar文件并复制依赖项只需使用mvn install即可。

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