@Conditional的用法

@Conditional進行條件判斷： 符合條件則加載該bean，不符合則不加載該bean 示例

1、用於測試的bean實體

package com.bean;

/**
 * @auto dh
 * @create 2020-04-25-15:10
 */
public class Animal {
}

package com.bean;

/**
 * @auto dh
 * @create 2020-04-25-11:00
 */
public class Person {
}

2、實現condition的類

package com.condition;


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

/**
 * @auto dh
 * @create 2020-04-25-15:11
 */
public class Condition001 implements Condition {
    @Override
    public boolean matches(ConditionContext context, AnnotatedTypeMetadata annotatedTypeMetadata) {
//      context 代表Ioc容器  context.getBeanFactory 從Ioc容器里獲取容器工廠  
//　　　　調用該容器工廠，判斷是否包含該bean名為animal
        if(context.getBeanFactory().containsBean("animal")){
            return true;
        }
        return false;
    }
}

3、配置類

package com.configuration;

import com.bean.Animal;
import com.bean.Person;
import com.condition.Condition001;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;

/**
 * @auto dh
 * @create 2020-04-25-15:15
 */
@Configuration
public class ConditionTest001 {
//    @Bean
    public Animal animal() {
        return new Animal();
    }

    @Bean
//    如果Condition001.class返回true,則加載該bean,
//        否則不加載該bean
    @Conditional(Condition001.class)
    public Person person() {
        return new Person();
    }

}
4、測試類

package com.test;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

/**
 * @auto dh
 * @create 2020-04-25-15:16
 */
public class ConditionTest001 {
    public static void main(String[] args) {
        AnnotationConfigApplicationContext ctx=new AnnotationConfigApplicationContext(com.configuration.ConditionTest001.class);
        String[] beans=ctx.getBeanDefinitionNames();
        for(String str:beans){
            System.out.println("bean信息："+str);
        }
    }
}