Как разрешить зависимость org.apache.kafka.clients.producer.Producer в проекте maven как производитель java для apache kafka

Question

Это контроллер для моего веб-приложения java. упаковка com.proj.controller;

import org.springframework.web.bind.annotation.RequestBody; 
import org.springframework.web.bind.annotation.RequestMapping; 
import org.springframework.web.bind.annotation.RequestMethod; 
import org.springframework.web.bind.annotation.ResponseBody; 
import org.springframework.web.bind.annotation.RestController; 

import com.proj.dao.Kafka_ObjectDao; 
import com.proj.daoImpl.Kafka_ObjectDaoImpl; 
import com.proj.model.Kafka_Object; 

@RestController 
public class MainController { 

Kafka_ObjectDao kafka_ObjectDao = new Kafka_ObjectDaoImpl(); 

@RequestMapping("/") 
public String welcome() { 

    return "<h1>Welcome to Rest Services for Kafka</h1><br><br>"; 
} 

@RequestMapping(value = "/modify/student", method = RequestMethod.POST) 
    public @ResponseBody int modifyStudent(@RequestBody Kafka_Object kafka_Object) 
{ 
    System.out.println("In controller"); 
    return kafka_ObjectDao.modifyStudent(kafka_Object); 

    } 
} 

Дао для этого веб-приложения пакет com.proj.dao;

import com.proj.model.Kafka_Object; 

public interface Kafka_ObjectDao { 

    public int modifyStudent(Kafka_Object kafka_Object); 

} 

Реализация для интерфейса дао является

package com.proj.daoImpl; 
import java.util.Properties; 
import org.apache.kafka.clients.producer.KafkaProducer; 
import org.apache.kafka.clients.producer.Producer; 
import org.apache.kafka.clients.producer.ProducerRecord; 

import com.google.gson.Gson; 
import com.proj.dao.Kafka_ObjectDao; 
import com.proj.model.Kafka_Object; 

public class Kafka_ObjectDaoImpl implements Kafka_ObjectDao { 
Gson gson = new Gson(); 

public Kafka_ObjectDaoImpl() { 
} 

public int modifyStudent(Kafka_Object pojo) { 
    Properties props = new Properties(); 
    props.put("bootstrap.servers", "localhost:9092"); 
    props.put("acks", "all"); 
    props.put("retries", 0); 
    props.put("batch.size", 16384); 
    props.put("linger.ms", 1); 
    props.put("buffer.memory", 33554432); 
    props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer"); 
    props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer"); 
    try { 
     Producer<String, String> producer = new KafkaProducer<String, String>(props); 
     ProducerRecord<String, String> PR = new ProducerRecord<String, String>("test", gson.toJson(pojo)); 
     producer.send(PR); 
     System.out.println("Sent:" + PR.toString()); 
     producer.close(); 
    } catch (Exception e) { 
     e.printStackTrace(); 
    } 
    return 1; 
} 

}

Конфигурация приложения для данного веб-приложения

package com.proj.config; 
import org.springframework.context.annotation.Bean; 
import org.springframework.context.annotation.ComponentScan; 
import org.springframework.context.annotation.Configuration; 

import com.proj.dao.Kafka_ObjectDao; 
import com.proj.daoImpl.Kafka_ObjectDaoImpl; 

@Configuration 
@ComponentScan(basePackages = "com.proj") 
public class ApplicationConfig { 

@Bean 
public Kafka_ObjectDao getKafka_ObjectDao() { 
    return new Kafka_ObjectDaoImpl(); 
} 
} 

pom.xml для моего Maven проекта

<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/maven-v4_0_0.xsd"> 
<modelVersion>4.0.0</modelVersion> 
<groupId>com.rest</groupId> 
<artifactId>QIC_FIRST</artifactId> 
<packaging>war</packaging> 
<version>1.0-SNAPSHOT</version> 
<name>QIC_FIRST Maven Webapp</name> 
<url>http://maven.apache.org</url> 
<dependencies> 
    <dependency> 
     <groupId>junit</groupId> 
     <artifactId>junit</artifactId> 
     <version>3.8.1</version> 
     <scope>test</scope> 
    </dependency> 
    <dependency> 
     <groupId>org.apache.kafka</groupId> 
     <artifactId>kafka-clients</artifactId> 
     <version>0.9.0.1</version> 
     <scope>provided</scope> 
    </dependency> 
    <dependency> 
     <groupId>org.apache.kafka</groupId> 
     <artifactId>kafka_2.10</artifactId> 
     <version>0.10.0.0</version> 
    </dependency> 
    <dependency> 
     <groupId>com.google.code.gson</groupId> 
     <artifactId>gson</artifactId> 
     <version>2.6.2</version> 
    </dependency> 
    <dependency> 
     <groupId>org.springframework.data</groupId> 
     <artifactId>spring-data-rest-webmvc</artifactId> 
     <version>2.4.2.RELEASE</version> 
    </dependency> 
    <dependency> 
     <groupId>javax.servlet</groupId> 
     <artifactId>javax.servlet-api</artifactId> 
     <version>3.1.0</version> 
    </dependency> 
    <dependency> 
     <groupId>org.springframework</groupId> 
     <artifactId>spring-jdbc</artifactId> 
     <version>4.3.0.RELEASE</version> 
    </dependency> 
    <dependency> 
     <groupId>com.google.code.gson</groupId> 
     <artifactId>gson</artifactId> 
     <version>2.6.2</version> 
    </dependency> 
</dependencies> 
<build> 
    <finalName>QIC_FIRST</finalName> 
</build> 
</project> 

ошибка, что я получаю

Caused by: java.lang.ClassNotFoundException:org.apache.kafka.clients.producer.Producer 

Полный список ошибок является

SEVERE: Exception sending context initialized event to listener instance  of class org.springframework.web.context.ContextLoaderListener 
    org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mainController' defined in file   [C:\Users\teja.k\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp2\wtpwebapps\QIC_FIRST\WEB-INF\classes\com\proj\controller\MainController.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.proj.controller.MainController]: Constructor threw exception; nested exception is java.lang.NoClassDefFoundError: org/apache/kafka/clients/producer/Producer 
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1105) 
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1050) 
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:510) 
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) 
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) 
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) 
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) 
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) 
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:775) 
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:762) 
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480) 
at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:434) 
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:306) 
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106) 
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:5097) 
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5615) 
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147) 
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1571) 
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1561) 
at java.util.concurrent.FutureTask.run(FutureTask.java:266) 
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) 
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) 
at java.lang.Thread.run(Thread.java:745) 
    Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.proj.controller.MainController]: Constructor threw exception; nested exception is java.lang.NoClassDefFoundError: org/apache/kafka/clients/producer/Producer 
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:159) 
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:89) 
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1098) 
... 22 more 
Caused by: java.lang.NoClassDefFoundError: org/apache/kafka/clients/producer/Producer 
at com.proj.controller.MainController.<init>(MainController.java:16) 
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) 
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) 
at java.lang.reflect.Constructor.newInstance(Constructor.java:422) 
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:147) 
... 24 more 
    Caused by: java.lang.ClassNotFoundException: org.apache.kafka.clients.producer.Producer 
at  org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase .java:1891) 
at   org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1734) 
... 30 more 

Спасибо заранее.

Answer 1

Ваша kafka-clients зависимость имеет область provided. Это должно быть compile или runtime. Объем provided не будет устанавливать зависимость в файл .jar. Если вы используете provided, вам нужно вручную добавить .jar в свой путь к классам другими способами. Самое простое решение - удалить <scope>provided</scope> из вашей зависимости kafka-clients.