NiFI 自定义处理器 ClassNotFoundException答案

【问题标题】：NiFI custom processor ClassNotFoundExceptionNiFI 自定义处理器 ClassNotFoundException
【发布时间】：2017-03-14 05:03:24
【问题描述】：

我正在尝试加载自定义 NiFi 处理器，但无法让 NiFi 加载我所有的 .nar 依赖项，尽管尝试了各种 pom.xml 配置。我在 SO 上遇到过一些类似的问题，但没有找到这个问题的答案。

我使用 mvn clean install 将我的处理器打包为 .nar，然后将 .nar 复制到 NIFI_HOME/lib。目前我得到java.lang.ClassNotFoundException: org.apache.http.conn.HttpClientConnectionManager。当前 pom 依赖项：

<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>
    <nifi.version>1.1.2</nifi.version>
</properties>
<dependencies>
    <dependency>
        <groupId>org.apache.nifi</groupId>
        <artifactId>nifi-api</artifactId>
        <version>${nifi.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.nifi</groupId>
        <artifactId>nifi-utils</artifactId>
        <version>${nifi.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.nifi</groupId>
        <artifactId>nifi-standard-services-api-nar</artifactId>
        <version>${nifi.version}</version>
        <type>nar</type>
    </dependency>
    <dependency>
        <groupId>org.apache.nifi</groupId>
        <artifactId>nifi-ssl-context-service</artifactId>
        <version>${nifi.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.nifi</groupId>
        <artifactId>nifi-ssl-context-service-api</artifactId>
        <version>${nifi.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.nifi</groupId>
        <artifactId>nifi-processor-utils</artifactId>
        <version>${nifi.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.httpcomponents</groupId>
        <artifactId>httpclient</artifactId>
        <version>4.4.1</version>
    </dependency>
    <dependency>
        <groupId>org.apache.httpcomponents</groupId>
        <artifactId>httpcore</artifactId>
        <version>4.4.1</version>
    </dependency>
    <dependency>
        <groupId>joda-time</groupId>
        <artifactId>joda-time</artifactId>
        <version>2.9.7</version>
    </dependency>
</dependencies>

我 nar 的 NIFI_HOME/.../bundled-dependencies/ 包含所有指定的 jar：

bcpkix-jdk15on-1.55.jar                joda-time-2.9.7.jar
bcprov-jdk15on-1.55.jar                nifi-api-1.1.2.jar
commons-codec-1.9.jar                  nifi-processor-utils-1.1.2.jar
commons-io-2.5.jar                     nifi-security-utils-1.1.2.jar
commons-lang3-3.4.jar                  nifi-ssl-context-service-1.1.2.jar
commons-logging-1.2.jar                nifi-ssl-context-service-api-1.1.2.jar
httpclient-4.4.1.jar                   nifi-utils-1.1.2.jar
httpcore-4.4.1.jar

完整的堆栈跟踪：

2017-03-13 11:11:23,146 ERROR [main] org.apache.nifi.NiFi Failure to launch NiFi due to java.util.ServiceConfigurationError: org.apache.nifi.processor.Processor: Provider com.alar.nifi.processors.GetIBright could not be instantiated
java.util.ServiceConfigurationError: org.apache.nifi.processor.Processor: Provider com.alar.nifi.processors.GetIBright could not be instantiated
    at java.util.ServiceLoader.fail(ServiceLoader.java:232) ~[na:1.8.0_111]
    at java.util.ServiceLoader.access$100(ServiceLoader.java:185) ~[na:1.8.0_111]
    at java.util.ServiceLoader$LazyIterator.nextService(ServiceLoader.java:384) ~[na:1.8.0_111]
    at java.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:404) ~[na:1.8.0_111]
    at java.util.ServiceLoader$1.next(ServiceLoader.java:480) ~[na:1.8.0_111]
    at org.apache.nifi.nar.ExtensionManager.loadExtensions(ExtensionManager.java:116) ~[nifi-nar-utils-1.1.2.jar:1.1.2]
    at org.apache.nifi.nar.ExtensionManager.discoverExtensions(ExtensionManager.java:97) ~[nifi-nar-utils-1.1.2.jar:1.1.2]
    at org.apache.nifi.NiFi.<init>(NiFi.java:139) ~[nifi-runtime-1.1.2.jar:1.1.2]
    at org.apache.nifi.NiFi.main(NiFi.java:262) ~[nifi-runtime-1.1.2.jar:1.1.2]
Caused by: java.lang.NoClassDefFoundError: org/apache/http/conn/HttpClientConnectionManager
    at java.lang.Class.getDeclaredConstructors0(Native Method) ~[na:1.8.0_111]
    at java.lang.Class.privateGetDeclaredConstructors(Class.java:2671) ~[na:1.8.0_111]
    at java.lang.Class.getConstructor0(Class.java:3075) ~[na:1.8.0_111]
    at java.lang.Class.newInstance(Class.java:412) ~[na:1.8.0_111]
    at java.util.ServiceLoader$LazyIterator.nextService(ServiceLoader.java:380) ~[na:1.8.0_111]
    ... 6 common frames omitted
Caused by: java.lang.ClassNotFoundException: org.apache.http.conn.HttpClientConnectionManager
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381) ~[na:1.8.0_111]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_111]
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) ~[na:1.8.0_111]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_111]
    ... 11 common frames omitted

【问题讨论】：

能否提供类未找到异常的堆栈跟踪？
嗨，是的，我已将堆栈跟踪添加到问题中
@JustinMoore 希望您在将.jar 文件放在lib 文件夹下后重新启动NiFi 服务器
@Pons 是的，我已经重新启动了 NiFi，当它尝试在启动时加载新的自定义处理器时发生错误。另外 - 它是一个 .nar 文件，而不是 .jar
不正确的一件事（但不应与此问题相关）是您不应该在 NAR 中包含控制器服务 JAR。您的 NAR pom 应该对控制器服务 API 具有 NAR 依赖项，并且您的处理器 pom 应该对 API 具有提供的依赖项，以便它在编译时可用但在构建时不包含在内。 cwiki.apache.org/confluence/display/NIFI/…

标签： java apache-nifi

【解决方案1】：

通过将我的单个 pom.xml 修改为单独的构建 (nar) 和编译 (jar) pom.xml 文件以及父 pom.xml 来解决此问题。不知道为什么它以前不起作用，但我在下面包含了 pom.xml 文件

父 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>
    <artifactId>nifi-ibright-bundle</artifactId>
    <packaging>pom</packaging>
    <groupId>com.alar.nifi</groupId>
    <version>1.0-SNAPSHOT</version>

    <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>
        <nifi.version>1.1.2</nifi.version>
    </properties>

    <modules>
        <module>nifi-ibright-processor</module>
        <module>nifi-ibright-nar</module>
    </modules>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>com.alar.nifi</groupId>
                <artifactId>nifi-ibright-processor</artifactId>
                <version>1.0-SNAPSHOT</version>
            </dependency>
        </dependencies>
    </dependencyManagement> 
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.nifi</groupId>
                <artifactId>nifi-nar-maven-plugin</artifactId>
                <version>1.0.0-incubating</version>
                <extensions>true</extensions>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>2.15</version>
            </plugin>
        </plugins>
    </build>
</project>

nifi-ibright-nar/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">
    <parent>
        <groupId>com.alar.nifi</groupId>
        <artifactId>nifi-ibright-bundle</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.alar.nifi</groupId>
    <artifactId>nifi-ibright-processor</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>


    <dependencies>
        <dependency>
            <groupId>org.apache.nifi</groupId>
            <artifactId>nifi-api</artifactId>
            <version>${nifi.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.nifi</groupId>
            <artifactId>nifi-utils</artifactId>
            <version>${nifi.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.nifi</groupId>
            <artifactId>nifi-ssl-context-service-api</artifactId>
            <version>${nifi.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.nifi</groupId>
            <artifactId>nifi-processor-utils</artifactId>
            <version>${nifi.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.4.1</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpcore</artifactId>
            <version>4.4.1</version>
        </dependency>
        <dependency>
            <groupId>joda-time</groupId>
            <artifactId>joda-time</artifactId>
            <version>2.9.7</version>
        </dependency>
    </dependencies>

</project>

【讨论】：