[解決済み] Springbootでkafkaプロデューサーの構築に失敗しました。

質問

Springbootで簡単なkafkaのサンプルプロジェクトを行っていますが、プロデューサーが作成されないというエラーが発生し、他の部分はうまく動作します。

私が持っているエラーは、プロデューサーが作成されなかったので、それは例外を投げたようですが、なぜそれが説明されていませんし、私は知りません。

2019-06-05 14:45:21.733  INFO 5988 --- [nio-8080-exec-2] o.a.k.clients.producer.KafkaProducer     : [Producer clientId=producer-1] Closing the Kafka producer with timeoutMillis = 0 ms.
2019-06-05 14:45:21.755 ERROR 5988 --- [nio-8080-exec-2] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.apache.kafka.common.KafkaException: Failed to construct kafka producer] with root cause

java.lang.InstantiationException: null
    at java.base/jdk.internal.reflect.InstantiationExceptionConstructorAccessorImpl.newInstance(InstantiationExceptionConstructorAccessorImpl.java:48) ~[na:na]
    at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500) ~[na:na]
    at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:481) ~[na:na]
    at org.apache.kafka.common.utils.Utils.newInstance(Utils.java:306) ~[kafka-clients-2.0.1.jar:na]
    at org.apache.kafka.common.config.AbstractConfig.getConfiguredInstance(AbstractConfig.java:302) ~[kafka-clients-2.0.1.jar:na]
    at org.apache.kafka.clients.producer.KafkaProducer.<init>(KafkaProducer.java:370) ~[kafka-clients-2.0.1.jar:na]
    at org.apache.kafka.clients.producer.KafkaProducer.<init>(KafkaProducer.java:289) ~[kafka-clients-2.0.1.jar:na]
    at org.springframework.kafka.core.DefaultKafkaProducerFactory.createKafkaProducer(DefaultKafkaProducerFactory.java:318) ~[spring-kafka-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at org.springframework.kafka.core.DefaultKafkaProducerFactory.createProducer(DefaultKafkaProducerFactory.java:305) ~[spring-kafka-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at org.springframework.kafka.core.KafkaTemplate.getTheProducer(KafkaTemplate.java:446) ~[spring-kafka-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at org.springframework.kafka.core.KafkaTemplate.doSend(KafkaTemplate.java:376) ~[spring-kafka-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at org.springframework.kafka.core.KafkaTemplate.send(KafkaTemplate.java:193) ~[spring-kafka-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at com.example.kafka.KafkaSimpleController.post(KafkaSimpleController.java:24) ~[classes/:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Method.java:567) ~[na:na]
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104) ~[spring-webmvc-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:892) ~[spring-webmvc-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797) ~[spring-webmvc-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1039) ~[spring-webmvc-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942) ~[spring-webmvc-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005) ~[spring-webmvc-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:908) ~[spring-webmvc-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:660) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882) ~[spring-webmvc-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.19.jar:9.0.19]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92) ~[spring-web-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) ~[spring-web-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:200) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:836) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1747) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na]
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at java.base/java.lang.Thread.run(Thread.java:835) ~[na:na]

以下は私のカフカの設定です。

@Configuration
public class KafkaConfig {

    @Bean
    public ProducerFactory<String, SimpleModel> producerFactory() {
        Map<String, Object> config = new HashMap<>();

        config.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "127.0.0.1:9092");
        config.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
        config.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, JsonSerializer.class);

        return new DefaultKafkaProducerFactory<>(config);
    }

    @Bean
    public KafkaTemplate<String, SimpleModel> kafkaTemplate() {
        return new KafkaTemplate<>(producerFactory());
    }
}

ここでは、コントローラ、エンドポイント "/api/kafka"を指定しています。

@RestController
@RequestMapping("/api/kafka")
public class KafkaSimpleController {

    private KafkaTemplate<String, SimpleModel> kafkaTemplate;

    @Autowired
    public KafkaSimpleController(KafkaTemplate<String, SimpleModel> kafkaTemplate) {
        this.kafkaTemplate = kafkaTemplate;

    }

    @PostMapping
    public void post(@RequestBody SimpleModel simpleModel) {
        kafkaTemplate.send("myTopic", simpleModel);
    }
}

解決方法は？

私の方でも同じような問題が発生しました。 JsonSerializer クラスがあります。このインポートに変更しました。 org.springframework.kafka.support.serializer.JsonSerializer; すべてうまくいきました。