【Spring源码解析】组件注册-@Condition条件注册bean

前言

接上一篇 Spring源码解析之@Lazy懒加载Bean

未添加条件前

1. 配置

@Configuration
public class BeanConfig2 {

    @Lazy
    @Bean
    public Person person() {
        System.out.println("容器中注册Person...");
        return new Person("config", 18);
    }

    @Bean("linux")
    public Person person1() {
        return new Person("linux", 20);
    }

    @Bean("windows")
    public Person person2() {
        return new Person("windows", 21);
    }
}

2. 测试

/**
 * person
 * linux
 * windows
 * 容器中注册Person...
 * {person=Person{name='config', age=18}, linux=Person{name='linux', age=20}, windows=Person{name='windows', age=21}}
 */
@Test
public void test03() {
    AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(BeanConfig2.class);
    String[] beanNamesForType = applicationContext.getBeanNamesForType(Person.class);
    for (String name: beanNamesForType) {
        System.out.println(name);
    }
    Map<String, Person> beansOfType = applicationContext.getBeansOfType(Person.class);
    System.out.println(beansOfType);
}

条件注入

1. 条件配置

@Configuration
public class BeanConfig2 {

    @Lazy
    @Bean
    public Person person() {
        System.out.println("容器中注册Person...");
        return new Person("config", 18);
    }

    @Conditional({MacCondition.class})
    @Bean("mac")
    public Person person0() {
        return new Person("mac", 19);
    }

    @Conditional({LinuxCondition.class})
    @Bean("linux")
    public Person person1() {
        return new Person("linux", 20);
    }

    @Conditional({WindowsCondition.class})
    @Bean("windows")
    public Person person2() {
        return new Person("windows", 21);
    }
}

2. 条件实现

/**
 * @author cuishiying
 * @date 2021-01-22
 */
public class MacCondition implements Condition {
    @Override
    public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
        ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
        Environment environment = context.getEnvironment();
        BeanDefinitionRegistry registry = context.getRegistry();
        String[] beanDefinitionNames = registry.getBeanDefinitionNames();

        String property = environment.getProperty("os.name");
        if (property.contains("Mac")) {
            return true;
        }
        return false;
    }
}

其他条件类似~

3. 测试

/**
 * person
 * mac
 */
@Test
public void test04() {
    AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(BeanConfig2.class);
    String[] beanNamesForType = applicationContext.getBeanNamesForType(Person.class);
    for (String name: beanNamesForType) {
        System.out.println(name);
    }
}

最后

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