[英]Spring Autowired Component is null in bean method
我正在嘗試在@Configuration
class 中使用@Autowired
變量,其中在方法中使用@Bean
創建了一個 bean。 但是,我需要用來創建 bean 的組件是null
。
@Autowired
private JDAListener listener;
@Bean
public ShardManager shardManager() throws LoginException, IllegalArgumentException {
DefaultShardManagerBuilder builder = DefaultShardManagerBuilder.createDefault(this.botToken)
.enableIntents(GatewayIntent.GUILD_MEMBERS)
.setStatus(OnlineStatus.IDLE)
.setShardsTotal(this.totalShards)
.addEventListeners(Arrays.asList(this.listener)); //throws Exception
return builder.build();
}
我得到的異常如下:
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'config':
Unsatisfied dependency expressed through field 'shardManager'; nested exception is org.springframework.beans.factory.BeanCreationException:
Error creating bean with name 'shardManager' defined in class path resource [dev/teamnight/nightbot/Config.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException:
Failed to instantiate [net.dv8tion.jda.api.sharding.ShardManager]: Circular reference involving containing bean 'config' - consider declaring the factory method as static for independence from its containing instance. Factory method 'shardManager' threw exception;
nested exception is java.lang.IllegalArgumentException: listeners may not be null
我假設代碼片段是某種配置的一部分(用@Configuration
或什@SpringBootApplication
注釋的東西)。
在這種情況下:
JDAListener
也由 Spring 容器管理。shardManager
方法,將JDAListener
bean 的實例注入到分片管理器中您將得到如下所示的代碼:
@Configuration
public class MyConfiguration {
@Bean // now jda listener is managed by spring!
public JDAListener jdaListener() {
return new JDAListener();
}
@Bean // note the parameter to the method
public ShardManager shardManager(JDAListener jdaListener) throws LoginException, IllegalArgumentException {
DefaultShardManagerBuilder builder =
DefaultShardManagerBuilder.createDefault(this.botToken)
.enableIntents(GatewayIntent.GUILD_MEMBERS)
.setStatus(OnlineStatus.IDLE)
.setShardsTotal(this.totalShards)
.addEventListeners(Arrays.asList(jdaListener)); //throws Exception
return builder.build();
}
}
我認為您正面臨此問題,因為 Spring 試圖在注入偵聽器之前依賴注入 bean。 您也嘗試將 JdaListener 聲明為 bean 怎么樣?
JDAListener 是否被標記為@Component/@Service 或告訴框架它應該被視為 bean 的東西? 另外,快速檢查您的組件掃描配置。
我正在嘗試在@Configuration
class 中使用@Autowired
變量,其中在方法中使用@Bean
創建了一個bean。 但是,我需要創建 bean 的組件是null
。
@Autowired
private JDAListener listener;
@Bean
public ShardManager shardManager() throws LoginException, IllegalArgumentException {
DefaultShardManagerBuilder builder = DefaultShardManagerBuilder.createDefault(this.botToken)
.enableIntents(GatewayIntent.GUILD_MEMBERS)
.setStatus(OnlineStatus.IDLE)
.setShardsTotal(this.totalShards)
.addEventListeners(Arrays.asList(this.listener)); //throws Exception
return builder.build();
}
我得到的異常如下:
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'config':
Unsatisfied dependency expressed through field 'shardManager'; nested exception is org.springframework.beans.factory.BeanCreationException:
Error creating bean with name 'shardManager' defined in class path resource [dev/teamnight/nightbot/Config.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException:
Failed to instantiate [net.dv8tion.jda.api.sharding.ShardManager]: Circular reference involving containing bean 'config' - consider declaring the factory method as static for independence from its containing instance. Factory method 'shardManager' threw exception;
nested exception is java.lang.IllegalArgumentException: listeners may not be null
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