我正在尝试向Spring-Boot项目中添加一些自定义应用程序属性。 他们看起来像这样：
application:
kafka:
topic1: topicA
topic2: topicB
这是@ConfigurationProperties类：
@ConfigurationProperties(prefix = "application", ignoreUnknownFields = false)
public class ApplicationProperties {
public static class Kafka {
private String topic1;
private String topic2;
public String getTopic1() {
return topic1;
}
public void setTopic1(String topic1) {
this.topic1 = topic1;
}
public String getTopic2() {
return topic2;
}
public void setTopic2(String topic2) {
this.topic2 = topic2;
}
}
}
启动应用程序时，出现以下错误：
Error starting ApplicationContext. To display the auto-configuration report re-run your application with 'debug' enabled.
2018-11-16 16:13:04 [restartedMain] ERROR o.s.boot.SpringApplication - Application startup failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'application-com.project.config.ApplicationProperties': Could not bind properties to ApplicationProperties (prefix=application, ignoreInvalidFields=false, ignoreUnknownFields=false, ignoreNestedProperties=false); nested exception is org.springframework.beans.NotWritablePropertyException: Invalid property 'kafka[topic1]' of bean class [com.project.config.ApplicationProperties]: Cannot access indexed value in property referenced in indexed property path 'kafka[topic1]'; nested exception is org.springframework.beans.NotReadablePropertyException: Invalid property 'kafka[topic1]' of bean class [com.project.config.ApplicationProperties]: Bean property 'kafka[topic1]' is not readable or has an invalid getter method: Does the return type of the getter match the parameter type of the setter?
at org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor.postProcessBeforeInitialization(ConfigurationPropertiesBindingPostProcessor.java:336)
at org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor.postProcessBeforeInitialization(ConfigurationPropertiesBindingPostProcessor.java:292)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:409)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1626)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:312)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:308)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693)
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:303)
at com.project.projectApp.main(projectApp.java:68)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49)
Caused by: org.springframework.beans.NotWritablePropertyException: Invalid property 'kafka[topic1]' of bean class [com.project.config.ApplicationProperties]: Cannot access indexed value in property referenced in indexed property path 'kafka[topic1]'; nested exception is org.springframework.beans.NotReadablePropertyException: Invalid property 'kafka[topic1]' of bean class [com.project.config.ApplicationProperties]: Bean property 'kafka[topic1]' is not readable or has an invalid getter method: Does the return type of the getter match the parameter type of the setter?
at org.springframework.beans.AbstractNestablePropertyAccessor.getPropertyHoldingValue(AbstractNestablePropertyAccessor.java:403)
at org.springframework.beans.AbstractNestablePropertyAccessor.processKeyedProperty(AbstractNestablePropertyAccessor.java:296)
at org.springframework.beans.AbstractNestablePropertyAccessor.setPropertyValue(AbstractNestablePropertyAccessor.java:287)
at org.springframework.beans.AbstractNestablePropertyAccessor.setPropertyValue(AbstractNestablePropertyAccessor.java:278)
at org.springframework.boot.bind.RelaxedDataBinder$RelaxedBeanWrapper.setPropertyValue(RelaxedDataBinder.java:726)
at org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(AbstractPropertyAccessor.java:95)
at org.springframework.validation.DataBinder.applyPropertyValues(DataBinder.java:860)
at org.springframework.validation.DataBinder.doBind(DataBinder.java:756)
at org.springframework.boot.bind.RelaxedDataBinder.doBind(RelaxedDataBinder.java:137)
at org.springframework.validation.DataBinder.bind(DataBinder.java:741)
at org.springframework.boot.bind.PropertiesConfigurationFactory.doBindPropertiesToTarget(PropertiesConfigurationFactory.java:287)
at org.springframework.boot.bind.PropertiesConfigurationFactory.bindPropertiesToTarget(PropertiesConfigurationFactory.java:250)
at org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor.postProcessBeforeInitialization(ConfigurationPropertiesBindingPostProcessor.java:331)
... 22 common frames omitted
Caused by: org.springframework.beans.NotReadablePropertyException: Invalid property 'kafka[topic1]' of bean class [com.project.config.ApplicationProperties]: Bean property 'kafka[topic1]' is not readable or has an invalid getter method: Does the return type of the getter match the parameter type of the setter?
at org.springframework.beans.AbstractNestablePropertyAccessor.getPropertyValue(AbstractNestablePropertyAccessor.java:631)
at org.springframework.beans.AbstractNestablePropertyAccessor.getPropertyHoldingValue(AbstractNestablePropertyAccessor.java:400)
... 34 common frames omitted
应该如何在我的ApplicationProperties中声明它以便正确绑定？
答案 0 :(得分：2)
不确定为什么要这样，但是可以通过以下解决方案实现：
@Component
@ConfigurationProperties(prefix = "application", ignoreUnknownFields = false)
public class ApplicationProperties {
public static class Kafka {
private String topic1;
private String topic2;
public String getTopic1() {
return topic1;
}
public void setTopic1(String topic1) {
this.topic1 = topic1;
}
public String getTopic2() {
return topic2;
}
public void setTopic2(String topic2) {
this.topic2 = topic2;
}
}
private Kafka kafka;
public Kafka getKafka() {
return kafka;
}
public void setKafka(Kafka kafka) {
this.kafka = kafka;
}
}
答案 1 :(得分：1)
您的ApplicationProperties对象需要具有一个带有适当的getter和setter的字段，以存储Kafka对象的实例。该字段应命名为kafka以匹配配置文件中的内容：
@ConfigurationProperties(...)
public class ApplicationProperties {
public static class Kafka {
...
}
private Kafka kafka;
public Kafka getKafka() {
return kafka;
}
public void setKafka(Kafka aKafka) {
kafka = aKafka;
}
}