Spring - @Conditional全解

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作用

必须是@Conditional指定的条件成立，才给容器中添加组件，配置配里面的所有内容才生效

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扩展注解

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Code

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Bean1 Bean2

public class Bean1 {
   

    public Bean1() {
   
        System.out.println("我是Bean1的构造方法");
    }
}

public class Bean2 {
   

    public Bean2() {
   
        System.out.println("我是Bean2的构造方法");
    }
}

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自定义比较规则

import org.springframework.context.annotation.Condition;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.core.type.AnnotatedTypeMetadata;


public class ArtisanCondition implements Condition {
   

    @Override
    public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
   
        //判断容器中是否有bean1的组件
        if(context.getBeanFactory().containsBean("bean1")) {
   
            return true;
        }
        return false;
    }
}

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配置类

import com.tuling.testconditional.compent.Bean1;
import com.tuling.testconditional.compent.Bean2;
import com.tuling.testconditional.condition.ArtisanCondition;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Conditional;


public class MainConfig {
   

    @Bean
    public Bean1 bean1() {
   
        return new Bean1();
    }

	// 如果满足ArtisanCondition中定义的规则，就实例化Bean2 
    @Bean
    @Conditional(value = ArtisanCondition.class) 
    public Bean2 bean2() {
   
        return new Bean2();
    }
}

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测试类

import com.tuling.testconditional.config.MainConfig;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;


public class MainClass {
   

    public static void main(String[] args) {
   
        AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(MainConfig.class);
        for(String beanName:ctx.getBeanDefinitionNames()) {
   
            System.out.println("beanName:"+beanName);
        }

    }
}

为了测试效果

重新测试

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如何校验自动配置类是否生效

配置文件中增加

启用 debug=true属性；来让控制台打印自动配置报告

转载：https://blog.csdn.net/yangshangwei/article/details/115413988