class java.lang.String cannot be cast to class java.util.List (java.lang.String and java.util.List are in module java.base of loader 'bootstrap')

huangapple
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英文:

class java.lang.String cannot be cast to class java.util.List (java.lang.String and java.util.List are in module java.base of loader 'bootstrap')

问题

  1. Trying to use ReplyingKafkaTemplate to return the response from the service, but keep getting an error `java.lang.ClassCastException: class java.lang.String cannot be cast to class java.util.List (java.lang.String and java.util.List are in module java.base of loader 'bootstrap')`
  3. # Listener
  5. @KafkaListener(id = ProductTopicConstants.GET_PRODUCTS, topics = ProductTopicConstants.GET_PRODUCTS, splitIterables = false)
  6. @SendTo
  7. public List<Product> GetProducts(@Payload(required = false) String payload) {
  8.     List<Product> products = _productRepository.findAll();
  9.     return new ArrayList<>(products);
  10. }
  12. # KafkaConfiguration
  14. @Configuration
  15. public class KafkaConfiguration {
  16.     @Bean
  17.     public ReplyingKafkaTemplate<String, String, List<Product>> replyer(
  18.         ProducerFactory<String, String> pf,
  19.         ConcurrentKafkaListenerContainerFactory<String, List<Product>> containerFactory
  20.     ) {
  21.         containerFactory.setReplyTemplate(kafkaTemplate(pf));
  22.         ConcurrentMessageListenerContainer<String, List<Product>> container = replyContainer(containerFactory);
  23.         ReplyingKafkaTemplate<String, String, List<Product>> replyer = new ReplyingKafkaTemplate<>(pf, container);
  24.         return replyer;
  25.     }
  27.     @Bean
  28.     public ConcurrentMessageListenerContainer<String, List<Product>> replyContainer(
  29.         ConcurrentKafkaListenerContainerFactory<String, List<Product>> containerFactory
  30.     ) {
  31.         ConcurrentMessageListenerContainer<String, List<Product>> container =
  32.             containerFactory.createContainer(ProductTopicConstants.GET_PRODUCTS_CONTAINER);
  33.         container.getContainerProperties().setGroupId(ProductTopicConstants.GET_PRODUCTS_CONTAINER);
  34.         container.setBatchErrorHandler(new BatchLoggingErrorHandler());
  35.         return container;
  36.     }
  38.     @Bean
  39.     public KafkaTemplate<String, String> kafkaTemplate(ProducerFactory<String, String> pf) {
  40.         return new KafkaTemplate<>(pf);
  41.     }
  43.     @Bean
  44.     public NewTopic GetProducts() {
  45.         return TopicBuilder.name(ProductTopicConstants.GET_PRODUCTS).partitions(1).replicas(1).build();
  46.     }
  48.     @Bean
  49.     public NewTopic GetProductsContainer() {
  50.         return TopicBuilder.name(ProductTopicConstants.GET_PRODUCTS_CONTAINER).partitions(1).replicas(1).build();
  51.     }
  52. }
  54. # service
  56. @Service
  57. public class ProductProducer implements IProductProducer {
  58.     private final ReplyingKafkaTemplate<String, String, List<Product>> _replyTemplate;
  59.     private static final Logger LOG = LoggerFactory.getLogger(ProductProducer.class);
  61.     public ProductProducer(ReplyingKafkaTemplate<String, String, List<Product>> replyTemplate) {
  62.         this._replyTemplate = replyTemplate;
  63.     }
  65.     @Override
  66.     public List<ProductViewModel> GetProducts() throws InterruptedException, ExecutionException, TimeoutException {
  67.         RequestReplyFuture<String, String, List<Product>> future =
  68.             this._replyTemplate.sendAndReceive(new ProducerRecord<>(ProductTopicConstants.GET_PRODUCTS, 0, null, null));
  69.         LOG.info(future.getSendFuture().get(10, TimeUnit.SECONDS).getRecordMetadata().toString());
  70.         List<Product> value = future.get(10, TimeUnit.SECONDS).value(); --> Getting an error over here 
  71.         return List.of(new ProductViewModel("", "", 0, ""));
  72.     }
  73. }
  75. # Error
  77. Getting an error over here `List<Product> value = future.get(10, TimeUnit.SECONDS).value();`
  79. java.lang.ClassCastException: class java.lang.String cannot be cast to class java.util.List (java.lang.String and java.util.List are in module java.base of loader 'bootstrap')
  80.     at fete.bird.fetebirdproduct.service.producer.ProductProducer.GetProducts(ProductProducer.java:40) ~[main/:na]
  81.     ...

(代码部分已经翻译完毕，以下内容不再包含翻译。)

英文:

Trying to use ReplyingKafkaTemplate to return the response from the service, but keep getting an error java.lang.ClassCastException: class java.lang.String cannot be cast to class java.util.List (java.lang.String and java.util.List are in module java.base of loader &#39;bootstrap&#39;)

Listener

  1.  @KafkaListener(id = ProductTopicConstants.GET_PRODUCTS, topics = ProductTopicConstants.GET_PRODUCTS,splitIterables = false)
  2.     @SendTo
  3.     public List&lt;Product&gt; GetProducts(@Payload(required = false) String payload) {
  4.         List&lt;Product&gt; products = _productRepository.findAll();
  5.         return new ArrayList&lt;&gt;(products);
  6.     }

KafkaConfiguration

  1. @Configuration
  2. public class KafkaConfiguration {
  3.     @Bean
  4.     public ReplyingKafkaTemplate&lt;String, String, List&lt;Product&gt;&gt; replyer(ProducerFactory&lt;String, String&gt; pf,
  5.                                                                         ConcurrentKafkaListenerContainerFactory&lt;String, List&lt;Product&gt;&gt; containerFactory) {
  7.         containerFactory.setReplyTemplate(kafkaTemplate(pf));
  8.         ConcurrentMessageListenerContainer&lt;String, List&lt;Product&gt;&gt; container = replyContainer(containerFactory);
  9.         ReplyingKafkaTemplate&lt;String, String, List&lt;Product&gt;&gt; replyer = new ReplyingKafkaTemplate&lt;&gt;(pf, container);
  10.         return replyer;
  11.     }
  13.     @Bean
  14.     public ConcurrentMessageListenerContainer&lt;String, List&lt;Product&gt;&gt; replyContainer(
  15.             ConcurrentKafkaListenerContainerFactory&lt;String, List&lt;Product&gt;&gt; containerFactory) {
  17.         ConcurrentMessageListenerContainer&lt;String, List&lt;Product&gt;&gt; container =
  18.                 containerFactory.createContainer(ProductTopicConstants.GET_PRODUCTS_CONTAINER);
  19.         container.getContainerProperties().setGroupId(ProductTopicConstants.GET_PRODUCTS_CONTAINER);
  20.         container.setBatchErrorHandler(new BatchLoggingErrorHandler());
  21.         return container;
  22.     }
  24.     @Bean
  25.     public KafkaTemplate&lt;String, String&gt; kafkaTemplate(ProducerFactory&lt;String, String&gt; pf) {
  26.         return new KafkaTemplate&lt;&gt;(pf);
  27.     }
  31.    @Bean
  32.     public NewTopic GetProducts() {
  33.         return TopicBuilder.name(ProductTopicConstants.GET_PRODUCTS).partitions(1).replicas(1).build();
  34.     }
  35.     @Bean
  36.     public NewTopic GetProductsContainer() {
  37.         return TopicBuilder.name(ProductTopicConstants.GET_PRODUCTS_CONTAINER).partitions(1).replicas(1).build();
  38.     }
  40. }

service

  1. @Service
  2. public class ProductProducer implements IProductProducer{
  3.   private final ReplyingKafkaTemplate&lt;String, String, List&lt;Product&gt;&gt; _replyTemplate;
  4.     private static final Logger LOG = LoggerFactory.getLogger(ProductProducer.class);
  5.     public ProductProducer(ReplyingKafkaTemplate&lt;String, String, List&lt;Product&gt;&gt; replyTemplate) {
  6.         this._replyTemplate = replyTemplate;
  7.     }
  9.  @Override
  10.     public List&lt;ProductViewModel&gt; GetProducts() throws InterruptedException, ExecutionException, TimeoutException {
  11.         RequestReplyFuture&lt;String, String, List&lt;Product&gt;&gt; future =
  12.                 this._replyTemplate.sendAndReceive(new ProducerRecord&lt;&gt;(ProductTopicConstants.GET_PRODUCTS, 0, null, null));
  13.             LOG.info(future.getSendFuture().get(10, TimeUnit.SECONDS).getRecordMetadata().toString());
  14.             List&lt;Product&gt; value = future.get(10, TimeUnit.SECONDS).value(); --&gt; Getting an error over here 
  15.             return List.of(new ProductViewModel(&quot;&quot;,&quot;&quot;,0,&quot;&quot;));
  16.     }
  17. }

Error

Getting an error over here List&lt;Product&gt; value = future.get(10, TimeUnit.SECONDS).value();

  1. java.lang.ClassCastException: class java.lang.String cannot be cast to class java.util.List (java.lang.String and java.util.List are in module java.base of loader &#39;bootstrap&#39;)
  2. 	at fete.bird.fetebirdproduct.service.producer.ProductProducer.GetProducts(ProductProducer.java:40) ~[main/:na]
  3. 	at fete.bird.fetebirdproduct.api.v1.controller.ProductController.Products(ProductController.java:43) ~[main/:na]
  4. 	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
  5. 	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
  6. 	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
  7. 	at java.base/java.lang.reflect.Method.invoke(Method.java:564) ~[na:na]
  8. 	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
  9. 	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
  10. 	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
  11. 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:879) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
  12. 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
  13. 	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
  14. 	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
  15. 	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
  16. 	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
  17. 	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
  18. 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  19. 	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
  20. 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  21. 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  22. 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  23. 	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.36.jar:9.0.36]
  24. 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  25. 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  26. 	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
  27. 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
  28. 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  29. 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  30. 	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
  31. 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
  32. 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  33. 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  34. 	at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:93) ~[spring-boot-actuator-2.3.1.RELEASE.jar:2.3.1.RELEASE]
  35. 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
  36. 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  37. 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  38. 	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
  39. 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
  40. 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  41. 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  42. 	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  43. 	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  44. 	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  45. 	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  46. 	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  47. 	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  48. 	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  49. 	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  50. 	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  51. 	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  52. 	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  53. 	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  54. 	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) ~[na:na]
  55. 	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) ~[na:na]
  56. 	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
  57. 	at java.base/java.lang.Thread.run(Thread.java:832) ~[na:na]

Configuration

  1. spring:
  2.   profiles:
  3.     active: dev
  4.   kafka:
  5.     bootstrapAddress: localhost:9092
  6.     producer:
  7.       key-serializer: org.springframework.kafka.support.serializer.JsonSerializer
  8.       value-serializer: org.springframework.kafka.support.serializer.JsonSerializer
  9.     consumer:
  10.       key-deserializer: org.springframework.kafka.support.serializer.JsonDeserializer
  11.       value-deserializer: org.springframework.kafka.support.serializer.JsonDeserializer
  12.       auto-offset-reset: earliest
  13.       properties:
  14.         spring:
  15.           json:
  16.             trusted:
  17.               packages: *

答案1

得分: 1

  1. 我在包名前缺少 &#39;*&#39;
  3.     spring:
  4.       profiles:
  5.         active: dev
  6.       kafka:
  7.         bootstrapAddress: localhost:9092
  8.         producer:
  9.           key-serializer: org.springframework.kafka.support.serializer.JsonSerializer
  10.           value-serializer: org.springframework.kafka.support.serializer.JsonSerializer
  11.         consumer:
  12.           key-deserializer: org.springframework.kafka.support.serializer.JsonDeserializer
  13.           value-deserializer: org.springframework.kafka.support.serializer.JsonDeserializer
  14.           auto-offset-reset: earliest
  15.           properties:
  16.             spring:
  17.               json:
  18.                 trusted:
  19.                   packages: &#39;*&#39;
英文:

I was missing '*' at the package

  1. spring:
  2.   profiles:
  3.     active: dev
  4.   kafka:
  5.     bootstrapAddress: localhost:9092
  6.     producer:
  7.       key-serializer: org.springframework.kafka.support.serializer.JsonSerializer
  8.       value-serializer: org.springframework.kafka.support.serializer.JsonSerializer
  9.     consumer:
  10.       key-deserializer: org.springframework.kafka.support.serializer.JsonDeserializer
  11.       value-deserializer: org.springframework.kafka.support.serializer.JsonDeserializer
  12.       auto-offset-reset: earliest
  13.       properties:
  14.         spring:
  15.           json:
  16.             trusted:
  17.               packages: &#39;*&#39;

huangapple
  • 本文由 发表于 2020年7月25日 23:46:22
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