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SpringBoot解決同名類導(dǎo)致的bean名沖突bean name conflicts問(wèn)題

更新時(shí)間：2023年06月20日 09:37:14 作者：野猿新一

這篇文章主要介紹了SpringBoot解決同名類導(dǎo)致的bean名沖突bean name conflicts問(wèn)題，具有很好的參考價(jià)值，希望對(duì)大家有所幫助。如有錯(cuò)誤或未考慮完全的地方，望不吝賜教

SpringBoot同名類導(dǎo)致的bean名沖突bean name conflicts

問(wèn)題描述

項(xiàng)目中有兩個(gè)同名類都叫MyService，只是放在不同的包名下

package com.yeyuanxinyi;
@Service()
public class MyService {
}

package com.yeyuanxiner;
@Service()
public class MyService {
}

當(dāng)項(xiàng)目啟動(dòng)的時(shí)候會(huì)報(bào)如下錯(cuò)誤

Caused by: org.springframework.context.annotation.ConflictingBeanDefinitionException: Annotation-specified bean name 'MyService' for bean class [com.yeyuanxinyi.MyService] conflicts with existing, non-compatible bean definition of same name and class [com.yeyuanxiner.MyService]
   at org.springframework.context.annotation.ClassPathBeanDefinitionScanner.checkCandidate(ClassPathBeanDefinitionScanner.java:348)
   at org.springframework.context.annotation.ClassPathBeanDefinitionScanner.doScan(ClassPathBeanDefinitionScanner.java:286)
   at org.springframework.context.annotation.ComponentScanAnnotationParser.parse(ComponentScanAnnotationParser.java:132)
   at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:287)
   at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:242)
   at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:199)
   at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:167)
   ... 13 common frames omitted

解決方法

問(wèn)題分析：

由于以上兩個(gè)同名類在用@Service注解的時(shí)候未指定value值，所以Spring Boot默認(rèn)會(huì)以類名作為bean name，由于兩個(gè)類名相同導(dǎo)致了bean name相同的沖突

可以通過(guò)為同名類指定不同的bean name來(lái)解決問(wèn)題，上面兩個(gè)同名類修改后如下

再次運(yùn)行項(xiàng)目就不會(huì)報(bào)錯(cuò)了

package com.yeyuanxinyi;
@Service("MyService1")
public class MyService {
}

package com.yeyuanxiner;
@Service("MyService2")
public class MyService {
}

同理，以上解決方法也適用于@Component

package com.yeyuanxiner;
@Component("MyComponent1")
public class MyComponent {
}

SpringBoot不同包結(jié)構(gòu)下，同名類沖突導(dǎo)致服務(wù)啟動(dòng)失敗解決方案

項(xiàng)目背景：

兩個(gè)項(xiàng)目的包結(jié)構(gòu)和類名都很多相同，于是開(kāi)始考慮使用加一級(jí)包進(jìn)行隔離，類似于這種結(jié)構(gòu)

但是在啟動(dòng)的過(guò)程中，拋出來(lái)這樣的異常：

Caused by: org.springframework.context.annotation.ConflictingBeanDefinitionException: Annotation-specified bean name 'nameConflict' for bean class [xom.liuyun.beannameconflict.modelB.NameConflict] conflicts with existing, non-compatible bean definition of same name and class [xom.liuyun.beannameconflict.modelA.NameConflict]

at org.springframework.context.annotation.ClassPathBeanDefinitionScanner.checkCandidate(ClassPathBeanDefinitionScanner.java:348) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.springframework.context.annotation.ClassPathBeanDefinitionScanner.doScan(ClassPathBeanDefinitionScanner.java:286) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.springframework.context.annotation.ComponentScanAnnotationParser.parse(ComponentScanAnnotationParser.java:132) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:284) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:241) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:198) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]

at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:166) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]

... 13 common frames omitted。

原因：

spring提供兩種beanName生成策略，基于注解的sprong-boot默認(rèn)使用的是AnnotationBeanNameGenerator，它生成beanName的策略就是，取當(dāng)前類名（不是全限定類名）作為beanName。由此，如果出現(xiàn)不同包結(jié)構(gòu)下同樣的類名稱，肯定會(huì)出現(xiàn)沖突。

解決方案如下

1. 自己寫一個(gè)類實(shí)現(xiàn) org.springframework.beans.factory.support.BeanNameGeneraot接口

public class UniqueNameGenerator extends AnnotationBeanNameGenerator {
?? ? @Override
? ? public String generateBeanName(BeanDefinition definition, BeanDefinitionRegistry registry) {
? ? ? ? //全限定類名
? ? ? ? String beanName = definition.getBeanClassName();
? ? ? ? return beanName;
? ? }
}

2. 在啟動(dòng)類上加注解@ComponentScan(nameGenerator = UniqueNameGenerator.class)使剛才我們自定義的BeanName生成策略生效。　

@SpringBootApplication?
@ComponentScan(nameGenerator = UniqueNameGenerator.class)
public class BeanNameConflictApplication {??
? ? public static void main(String[] args) {?
? ? ? ? SpringApplication.run(BeanNameConflictApplication.class, args);?
? ? }?
}

這樣，問(wèn)題就可以解決了。