我正在用Springboot做一个简单的kafka示例项目,但出现了一个错误,即生产者没有创建,但是其余的都工作良好。
我所看到的错误似乎引发了异常,因为生产者未创建但未解释原因,我也不知道:
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]
这是我的kafka配置:
@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());
}
}
这里是控制器,端点“ / api / kafka”:
@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);
}
}
答案 0 :(得分:2)
从一开始我就遇到了类似的问题,我导入了错误的JsonSerializer
类。更改为此导入org.springframework.kafka.support.serializer.JsonSerializer;
一切都很好。
答案 1 :(得分:0)
在 kafkaConfiguration 的 config 文件下,更改导入。
导入应为:import org.springframework.kafka.support.serializer.JsonSerializer;
答案 2 :(得分:0)
@3barney 的解决方案帮助了我! Intellij IDE 为 JsonSerializer
类提供了 2 个选项,而我选择了错误的一个!正确的导入语句是 -
import org.springframework.kafka.support.serializer.JsonSerializer;