解决required a single bean, but 2 were found问题

背景：springboot整合shiro中自定义Realm时出现

错误描述

Parameter 0 of method getDefaultWebSecurityManager in cn.ken.springboot_shiro.config.ShiroConfig required a single bean, but 2 were found:

getRealm: defined by method ‘getRealm’ in class path resource [cn/ken/springboot_shiro/config/ShiroConfig.class]

iniClasspathRealm: defined by method ‘iniClasspathRealm’ in class path resource [org/apache/shiro/spring/boot/autoconfigure/ShiroAutoConfiguration.class]

Action:

Consider marking one of the beans as @Primary, updating the consumer to accept multiple beans, or using @Qualifier to identify the bean that should be consumed

场景再现

// 创建安全管理器
@Bean
public DefaultWebSecurityManager getDefaultWebSecurityManager(Realm realm){
    DefaultWebSecurityManager defaultWebSecurityManager = new DefaultWebSecurityManager();
    // 给安全管理器设置realm
    defaultWebSecurityManager.setRealm(realm);
    return defaultWebSecurityManager;
}

错误分析：容器中出现了两个Realm类型的Bean，注入时不知道选择哪一个

解决方法：在参数中注入Realm时指定bean的id以区分

// 创建安全管理器
@Bean
public DefaultWebSecurityManager getDefaultWebSecurityManager(@Qualifier("getRealm") Realm realm){
    DefaultWebSecurityManager defaultWebSecurityManager = new DefaultWebSecurityManager();
    // 给安全管理器设置realm
    defaultWebSecurityManager.setRealm(realm);
    return defaultWebSecurityManager;
}
// 创建自定义Realm
@Bean
public Realm getRealm(){
    return new CustomerRealm();
}

@Qualifier(“getRealm”)参数之所以为getRealm是因为下面@Bean的方法名为getRealm()