通过工厂方法实例化 Bean 失败；异常 org.springframework.beans.BeanInstantiationException
Bean instantiation via factory method failed; exception org.springframework.beans.BeanInstantiationException
我有以下 Spring Kafka 配置：
import org.apache.kafka.clients.producer.ProducerConfig;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.kafka.core.DefaultKafkaProducerFactory;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.kafka.core.ProducerFactory;
import java.util.HashMap;
import java.util.Map;
@Configuration
@RefreshScope
@ConfigurationProperties(prefix = "kafka.status.producer")
public class StatusKafkaProducerConfig {
private String keySerializer;
private String valueSerializer;
private String bootstrapServers;
public void setKeySerializer(String keySerializer) {
this.keySerializer = keySerializer;
}
public void setValueSerializer(String valueSerializer) {
this.valueSerializer = valueSerializer;
}
public void setBootstrapServers(String bootstrapServers) {
this.bootstrapServers = bootstrapServers;
}
@Bean
public Map<String, Object> producerConfigs() {
Map<String, Object> properties = new HashMap<>();
properties.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, keySerializer);
properties.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, valueSerializer);
properties.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
return properties;
}
@Bean
@RefreshScope
public KafkaTemplate<String, String> kafkaTemplate() {
return new KafkaTemplate<>(producerFactory());
}
@Bean
public ProducerFactory<String, String> producerFactory() {
return new DefaultKafkaProducerFactory<>(producerConfigs());
}
}
我将项目迁移到最新的 Spring cloud 2021.0.1 和 Spring Boot 2.6.6。但是我在启动时收到以下错误堆栈：
2022-04-30 19:14:08.350 ERROR 23684 --- [ main] o.s.boot.SpringApplication : Application run failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'producerFactory' defined in class path resource [com/test/StatusUpdateKafkaProducerConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.kafka.core.ProducerFactory]: Factory method 'producerFactory' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:658) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:486) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1352) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1195) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean[=12=](AbstractBeanFactory.java:335) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:953) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:918) ~[spring-context-5.3.19.jar:5.3.19]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.19.jar:5.3.19]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145) ~[spring-boot-2.6.7.jar:2.6.7]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:740) ~[spring-boot-2.6.7.jar:2.6.7]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:415) ~[spring-boot-2.6.7.jar:2.6.7]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) ~[spring-boot-2.6.7.jar:2.6.7]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1312) ~[spring-boot-2.6.7.jar:2.6.7]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1301) ~[spring-boot-2.6.7.jar:2.6.7]
at com.test.Application.main(Application.java:82) ~[main/:na]
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.kafka.core.ProducerFactory]: Factory method 'producerFactory' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:653) ~[spring-beans-5.3.19.jar:5.3.19]
... 19 common frames omitted
Caused by: java.lang.NullPointerException: null
at java.base/java.util.concurrent.ConcurrentHashMap.putVal(ConcurrentHashMap.java:1011) ~[na:na]
at java.base/java.util.concurrent.ConcurrentHashMap.putAll(ConcurrentHashMap.java:1089) ~[na:na]
at java.base/java.util.concurrent.ConcurrentHashMap.<init>(ConcurrentHashMap.java:852) ~[na:na]
at org.springframework.kafka.core.DefaultKafkaProducerFactory.<init>(DefaultKafkaProducerFactory.java:205) ~[spring-kafka-2.8.5.jar:2.8.5]
at org.springframework.kafka.core.DefaultKafkaProducerFactory.<init>(DefaultKafkaProducerFactory.java:168) ~[spring-kafka-2.8.5.jar:2.8.5]
at com.test.StatusUpdateKafkaProducerConfig.producerFactory(TransactionStatusUpdateKafkaProducerConfig.java:53) ~[commons-0.0.1-plain.jar:na]
at com.test.StatusUpdateKafkaProducerConfig$$EnhancerBySpringCGLIB$$e907de88.CGLIB$producerFactory[=12=](<generated>) ~[commons-0.0.1-plain.jar:na]
at com.test.StatusUpdateKafkaProducerConfig$$EnhancerBySpringCGLIB$$e907de88$$FastClassBySpringCGLIB$$db10662a.invoke(<generated>) ~[commons-0.0.1-plain.jar:na]
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:244) ~[spring-core-5.3.19.jar:5.3.19]
at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:331) ~[spring-context-5.3.19.jar:5.3.19]
at com.StatusUpdateKafkaProducerConfig$$EnhancerBySpringCGLIB$$e907de88.producerFactory(<generated>) ~[commons-0.0.1-plain.jar:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[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:568) ~[na:na]
at org.springframework.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:282) ~[spring-core-5.3.19.jar:5.3.19]
at org.springframework.cloud.context.scope.GenericScope$LockedScopedProxyFactoryBean.invoke(GenericScope.java:485) ~[spring-cloud-context-3.1.2.jar:3.1.2]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.19.jar:5.3.19]
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:763) ~[spring-aop-5.3.19.jar:5.3.19]
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:708) ~[spring-aop-5.3.19.jar:5.3.19]
at com.StatusUpdateKafkaProducerConfig$$EnhancerBySpringCGLIB$00bd04.producerFactory(<generated>) ~[commons-0.0.1-plain.jar:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[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:568) ~[na:na]
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.3.19.jar:5.3.19]
... 20 common frames omitted
你知道我该如何解决这个问题吗？
错误堆栈跟踪表明在 producerFactory() 方法中创建 DefaultKafkaProducerFactory 的新实例时发生了 NullPointerException。
在内部，DefaultKafkaProducerFactory creates a ConcurrentHashMap 使用提供的信息来维护其配置。
正如您在 ConcurrentHashMap javadocs 中看到的那样，如果提供的任何键或值是 null.[=44=，put 方法将引发 NullPointerException ]
因此，变量 keySerializer、valueSerializer 或 bootstrapServers 中的一个或多个变量可能为空。
我假设这些值是根据您的 @ConfigurationProperties kafka.status.producer 通过依赖注入填充的。请确保在您的 Spring 配置中正确定义了这些属性。
出于测试目的，请尝试删除 @RefreshScope 注释：这可能是问题的原因。
反之亦然。如 Spring 云文档中所示 talking about @RefreshScope:
@RefreshScope works (technically) on a @Configuration class,
but it might lead to surprising behavior. For example, it does not
mean that all the @Beans defined in that class are themselves in
@RefreshScope. Specifically, anything that depends on those beans
cannot rely on them being updated when a refresh is initiated, unless
it is itself in @RefreshScope. In that case, it is rebuilt on a
refresh and its dependencies are re-injected. At that point, they are
re-initialized from the refreshed @Configuration).
从这个角度来看，如果用 @RefreshScope 注释 producerFactory bean 也是完全合理的。我会尝试：
import org.apache.kafka.clients.producer.ProducerConfig;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.kafka.core.DefaultKafkaProducerFactory;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.kafka.core.ProducerFactory;
import java.util.HashMap;
import java.util.Map;
@Configuration
@RefreshScope
@ConfigurationProperties(prefix = "kafka.status.producer")
public class StatusKafkaProducerConfig {
private String keySerializer;
private String valueSerializer;
private String bootstrapServers;
public void setKeySerializer(String keySerializer) {
this.keySerializer = keySerializer;
}
public void setValueSerializer(String valueSerializer) {
this.valueSerializer = valueSerializer;
}
public void setBootstrapServers(String bootstrapServers) {
this.bootstrapServers = bootstrapServers;
}
@Bean
@RefreshScope
public Map<String, Object> producerConfigs() {
Map<String, Object> properties = new HashMap<>();
properties.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, keySerializer);
properties.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, valueSerializer);
properties.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
return properties;
}
@Bean
@RefreshScope
public KafkaTemplate<String, String> kafkaTemplate() {
return new KafkaTemplate<>(producerFactory());
}
@Bean
@RefreshScope
public ProducerFactory<String, String> producerFactory() {
return new DefaultKafkaProducerFactory<>(producerConfigs());
}
}
请注意包含额外的 @RefreshScope 注释。
最后，考虑查看 Spring Kafka 项目文档，它提供了几个关于如何配置项目的示例，无论您是否使用 Spring Boot or not, and gives you further background about DefaultKafkaProducerFactory。
如您在上述文档中所见，如果您使用 Spring Boot，就像您的情况一样，代码可以大大简化。考虑查看 Spring Boot related documentation about the subject and related properties configuration.
我有以下 Spring Kafka 配置：
import org.apache.kafka.clients.producer.ProducerConfig;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.kafka.core.DefaultKafkaProducerFactory;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.kafka.core.ProducerFactory;
import java.util.HashMap;
import java.util.Map;
@Configuration
@RefreshScope
@ConfigurationProperties(prefix = "kafka.status.producer")
public class StatusKafkaProducerConfig {
private String keySerializer;
private String valueSerializer;
private String bootstrapServers;
public void setKeySerializer(String keySerializer) {
this.keySerializer = keySerializer;
}
public void setValueSerializer(String valueSerializer) {
this.valueSerializer = valueSerializer;
}
public void setBootstrapServers(String bootstrapServers) {
this.bootstrapServers = bootstrapServers;
}
@Bean
public Map<String, Object> producerConfigs() {
Map<String, Object> properties = new HashMap<>();
properties.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, keySerializer);
properties.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, valueSerializer);
properties.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
return properties;
}
@Bean
@RefreshScope
public KafkaTemplate<String, String> kafkaTemplate() {
return new KafkaTemplate<>(producerFactory());
}
@Bean
public ProducerFactory<String, String> producerFactory() {
return new DefaultKafkaProducerFactory<>(producerConfigs());
}
}
我将项目迁移到最新的 Spring cloud 2021.0.1 和 Spring Boot 2.6.6。但是我在启动时收到以下错误堆栈：
2022-04-30 19:14:08.350 ERROR 23684 --- [ main] o.s.boot.SpringApplication : Application run failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'producerFactory' defined in class path resource [com/test/StatusUpdateKafkaProducerConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.kafka.core.ProducerFactory]: Factory method 'producerFactory' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:658) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:486) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1352) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1195) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean[=12=](AbstractBeanFactory.java:335) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:953) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:918) ~[spring-context-5.3.19.jar:5.3.19]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.19.jar:5.3.19]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145) ~[spring-boot-2.6.7.jar:2.6.7]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:740) ~[spring-boot-2.6.7.jar:2.6.7]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:415) ~[spring-boot-2.6.7.jar:2.6.7]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) ~[spring-boot-2.6.7.jar:2.6.7]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1312) ~[spring-boot-2.6.7.jar:2.6.7]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1301) ~[spring-boot-2.6.7.jar:2.6.7]
at com.test.Application.main(Application.java:82) ~[main/:na]
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.kafka.core.ProducerFactory]: Factory method 'producerFactory' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) ~[spring-beans-5.3.19.jar:5.3.19]
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:653) ~[spring-beans-5.3.19.jar:5.3.19]
... 19 common frames omitted
Caused by: java.lang.NullPointerException: null
at java.base/java.util.concurrent.ConcurrentHashMap.putVal(ConcurrentHashMap.java:1011) ~[na:na]
at java.base/java.util.concurrent.ConcurrentHashMap.putAll(ConcurrentHashMap.java:1089) ~[na:na]
at java.base/java.util.concurrent.ConcurrentHashMap.<init>(ConcurrentHashMap.java:852) ~[na:na]
at org.springframework.kafka.core.DefaultKafkaProducerFactory.<init>(DefaultKafkaProducerFactory.java:205) ~[spring-kafka-2.8.5.jar:2.8.5]
at org.springframework.kafka.core.DefaultKafkaProducerFactory.<init>(DefaultKafkaProducerFactory.java:168) ~[spring-kafka-2.8.5.jar:2.8.5]
at com.test.StatusUpdateKafkaProducerConfig.producerFactory(TransactionStatusUpdateKafkaProducerConfig.java:53) ~[commons-0.0.1-plain.jar:na]
at com.test.StatusUpdateKafkaProducerConfig$$EnhancerBySpringCGLIB$$e907de88.CGLIB$producerFactory[=12=](<generated>) ~[commons-0.0.1-plain.jar:na]
at com.test.StatusUpdateKafkaProducerConfig$$EnhancerBySpringCGLIB$$e907de88$$FastClassBySpringCGLIB$$db10662a.invoke(<generated>) ~[commons-0.0.1-plain.jar:na]
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:244) ~[spring-core-5.3.19.jar:5.3.19]
at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:331) ~[spring-context-5.3.19.jar:5.3.19]
at com.StatusUpdateKafkaProducerConfig$$EnhancerBySpringCGLIB$$e907de88.producerFactory(<generated>) ~[commons-0.0.1-plain.jar:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:568) ~[na:na]
at org.springframework.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:282) ~[spring-core-5.3.19.jar:5.3.19]
at org.springframework.cloud.context.scope.GenericScope$LockedScopedProxyFactoryBean.invoke(GenericScope.java:485) ~[spring-cloud-context-3.1.2.jar:3.1.2]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.19.jar:5.3.19]
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:763) ~[spring-aop-5.3.19.jar:5.3.19]
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:708) ~[spring-aop-5.3.19.jar:5.3.19]
at com.StatusUpdateKafkaProducerConfig$$EnhancerBySpringCGLIB$00bd04.producerFactory(<generated>) ~[commons-0.0.1-plain.jar:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[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:568) ~[na:na]
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.3.19.jar:5.3.19]
... 20 common frames omitted
你知道我该如何解决这个问题吗？
错误堆栈跟踪表明在 producerFactory() 方法中创建 DefaultKafkaProducerFactory 的新实例时发生了 NullPointerException。
在内部，DefaultKafkaProducerFactory creates a ConcurrentHashMap 使用提供的信息来维护其配置。
正如您在 ConcurrentHashMap javadocs 中看到的那样，如果提供的任何键或值是 null.[=44=，put 方法将引发 NullPointerException ]
因此，变量 keySerializer、valueSerializer 或 bootstrapServers 中的一个或多个变量可能为空。
我假设这些值是根据您的 @ConfigurationProperties kafka.status.producer 通过依赖注入填充的。请确保在您的 Spring 配置中正确定义了这些属性。
出于测试目的，请尝试删除 @RefreshScope 注释：这可能是问题的原因。
反之亦然。如 Spring 云文档中所示 talking about @RefreshScope:
@RefreshScopeworks (technically) on a@Configurationclass, but it might lead to surprising behavior. For example, it does not mean that all the@Beansdefined in that class are themselves in@RefreshScope. Specifically, anything that depends on those beans cannot rely on them being updated when a refresh is initiated, unless it is itself in@RefreshScope. In that case, it is rebuilt on a refresh and its dependencies are re-injected. At that point, they are re-initialized from the refreshed@Configuration).
从这个角度来看，如果用 @RefreshScope 注释 producerFactory bean 也是完全合理的。我会尝试：
import org.apache.kafka.clients.producer.ProducerConfig;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.kafka.core.DefaultKafkaProducerFactory;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.kafka.core.ProducerFactory;
import java.util.HashMap;
import java.util.Map;
@Configuration
@RefreshScope
@ConfigurationProperties(prefix = "kafka.status.producer")
public class StatusKafkaProducerConfig {
private String keySerializer;
private String valueSerializer;
private String bootstrapServers;
public void setKeySerializer(String keySerializer) {
this.keySerializer = keySerializer;
}
public void setValueSerializer(String valueSerializer) {
this.valueSerializer = valueSerializer;
}
public void setBootstrapServers(String bootstrapServers) {
this.bootstrapServers = bootstrapServers;
}
@Bean
@RefreshScope
public Map<String, Object> producerConfigs() {
Map<String, Object> properties = new HashMap<>();
properties.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, keySerializer);
properties.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, valueSerializer);
properties.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
return properties;
}
@Bean
@RefreshScope
public KafkaTemplate<String, String> kafkaTemplate() {
return new KafkaTemplate<>(producerFactory());
}
@Bean
@RefreshScope
public ProducerFactory<String, String> producerFactory() {
return new DefaultKafkaProducerFactory<>(producerConfigs());
}
}
请注意包含额外的 @RefreshScope 注释。
最后，考虑查看 Spring Kafka 项目文档，它提供了几个关于如何配置项目的示例，无论您是否使用 Spring Boot or not, and gives you further background about DefaultKafkaProducerFactory。
如您在上述文档中所见，如果您使用 Spring Boot，就像您的情况一样，代码可以大大简化。考虑查看 Spring Boot related documentation about the subject and related properties configuration.