SpringBoot/spring-kafka 应用程序中的自动装配 KafkaTemplate 抛出空指针
Autowired KafkaTemplate in SpringBoot/spring-kafka application throws null pointer
我正在尝试在 Spring 引导应用程序中使用 spring-kafka KafkaTemplate 将消息写入 Kafka 主题。
我创建了一个 KafkaConfig class:
@Configuration
@EnableKafka
public class KafkaConfig {
@Value("${kafka.broker.address}")
private String brokerAddress;
@Bean
public ProducerFactory<Integer, String> producerFactory() {
return new DefaultKafkaProducerFactory<>(producerConfigs());
}
@Bean
public Map<String, Object> producerConfigs() {
Map<String, Object> props = new HashMap<>();
props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, brokerAddress);
props.put(ProducerConfig.RETRIES_CONFIG, 0);
props.put(ProducerConfig.BATCH_SIZE_CONFIG, 16384);
props.put(ProducerConfig.LINGER_MS_CONFIG, 1);
props.put(ProducerConfig.BUFFER_MEMORY_CONFIG, 33554432);
props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, IntegerSerializer.class);
props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
return props;
}
@Bean
public KafkaTemplate<Integer, String> kafkaTemplate() {
return new KafkaTemplate<Integer, String>(producerFactory());
}
}
... 并在我写入 Kafka 的 class 中自动连接 KafkaTemplate：
@Autowired
private KafkaTemplate<Integer, String> template;
由于某种原因，自动装配似乎不起作用。我注意到当我在调试中 运行 时 KafkaTemplate 为空：
此对象不应为空；它应该是一个 KafkaTemplate 对象。这会抛出一个空指针异常：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'watchService': Invocation of init method failed; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:136) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:408) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1570) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:776) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:861) ~[spring-context-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541) ~[spring-context-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:369) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:313) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1185) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1174) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE]
at io.woolford.Application.main(Application.java:11) [classes/:na]
Caused by: java.lang.NullPointerException: null
at io.woolford.WatchService.monitor(WatchService.java:93) ~[classes/:na]
at io.woolford.WatchService.watchPath(WatchService.java:37) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_91]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_91]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_91]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_91]
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleElement.invoke(InitDestroyAnnotationBeanPostProcessor.java:365) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMethods(InitDestroyAnnotationBeanPostProcessor.java:310) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:133) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
... 17 common frames omitted
kafka-spring 过去使用几乎相同的代码对我来说效果很好，所以我有点困惑为什么这次自动装配不起作用。你能看出我做错了什么吗？
您使用 bean 的时间太早了...
postProcessBeforeInitialization
...在设置属性之前调用。
编辑
实施SmartLifecycle并移动
watchService.monitor(path);
至start()。
EDIT2
也就是说；这很奇怪...
WatchService watchService = new WatchService();
watchService.monitor(path);
您正在 post 构造方法中创建一个新实例 - 当然它不会被自动装配，因为它不是由 Spring 管理的。
我正在尝试在 Spring 引导应用程序中使用 spring-kafka KafkaTemplate 将消息写入 Kafka 主题。
我创建了一个 KafkaConfig class:
@Configuration
@EnableKafka
public class KafkaConfig {
@Value("${kafka.broker.address}")
private String brokerAddress;
@Bean
public ProducerFactory<Integer, String> producerFactory() {
return new DefaultKafkaProducerFactory<>(producerConfigs());
}
@Bean
public Map<String, Object> producerConfigs() {
Map<String, Object> props = new HashMap<>();
props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, brokerAddress);
props.put(ProducerConfig.RETRIES_CONFIG, 0);
props.put(ProducerConfig.BATCH_SIZE_CONFIG, 16384);
props.put(ProducerConfig.LINGER_MS_CONFIG, 1);
props.put(ProducerConfig.BUFFER_MEMORY_CONFIG, 33554432);
props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, IntegerSerializer.class);
props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
return props;
}
@Bean
public KafkaTemplate<Integer, String> kafkaTemplate() {
return new KafkaTemplate<Integer, String>(producerFactory());
}
}
... 并在我写入 Kafka 的 class 中自动连接 KafkaTemplate：
@Autowired
private KafkaTemplate<Integer, String> template;
由于某种原因，自动装配似乎不起作用。我注意到当我在调试中 运行 时 KafkaTemplate 为空：
此对象不应为空；它应该是一个 KafkaTemplate 对象。这会抛出一个空指针异常：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'watchService': Invocation of init method failed; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:136) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:408) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1570) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:776) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:861) ~[spring-context-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541) ~[spring-context-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:369) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:313) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1185) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1174) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE]
at io.woolford.Application.main(Application.java:11) [classes/:na]
Caused by: java.lang.NullPointerException: null
at io.woolford.WatchService.monitor(WatchService.java:93) ~[classes/:na]
at io.woolford.WatchService.watchPath(WatchService.java:37) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_91]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_91]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_91]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_91]
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleElement.invoke(InitDestroyAnnotationBeanPostProcessor.java:365) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMethods(InitDestroyAnnotationBeanPostProcessor.java:310) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:133) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
... 17 common frames omitted
kafka-spring 过去使用几乎相同的代码对我来说效果很好，所以我有点困惑为什么这次自动装配不起作用。你能看出我做错了什么吗？
您使用 bean 的时间太早了...
postProcessBeforeInitialization
...在设置属性之前调用。
编辑
实施SmartLifecycle并移动
watchService.monitor(path);
至start()。
EDIT2
也就是说；这很奇怪...
WatchService watchService = new WatchService();
watchService.monitor(path);
您正在 post 构造方法中创建一个新实例 - 当然它不会被自动装配，因为它不是由 Spring 管理的。