如何解决maven项目中的依赖项org.apache.kafka.clients.producer.Producer作为apache kafka的{java}生成器

时间：2017-02-07 11:51:42

标签： java spring maven apache-kafka kafka-producer-api

这是我的java Web应用程序的控制器。         包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);

  } 
}

此Web应用程序的Dao是         包com.proj.dao; 

   import com.proj.model.Kafka_Object;

 public interface Kafka_ObjectDao {

  public int modifyStudent(Kafka_Object kafka_Object);

}

dao接口的实现是

    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;
}

}

此Web应用程序的应用程序配置是

    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();
}
}

我的maven项目的pom.xml是

    <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>

我得到的错误是

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

完整的错误列表是

    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

提前致谢。

1 个答案:

答案 0 :(得分：0)

您的kafka-clients依赖项的范围为provided。它应该是compile或runtime。范围provided不会将依赖项放入.jar文件中。如果您使用provided，则必须通过其他方式手动将.jar添加到类路径中。最简单的解决方案是从<scope>provided</scope>依赖项中删除kafka-clients。

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