SpringBoot2底层注解@Configuration配置类详解

@Configuration //告诉SpringBoot这是一个配置类 == 配置文件
public class MyConfig {
    @Bean("user1") //给容器中添加组件。以方法名作为组件的id。返回类型就是组件类型。返回的值，就是组件在容器中的实例
    public User user01(){
        return new User("pingguo", 20);
    }
    @Bean("pet1")
    public Pet tomcatPet(){
        return new Pet("tomcat");
    }
}

@SpringBootApplication(scanBasePackages = "com.pingguo")
public class MainApplication {
    public static void main(String[] args) {
        // 返回IOC容器
        final ConfigurableApplicationContext run = SpringApplication.run(MainApplication.class, args);
        // 查看容器里的组件
        final String[] beanDefinitionNames = run.getBeanDefinitionNames();
        for (String name: beanDefinitionNames) {
            System.out.println(name);
        }
        // 从容器中获取组件
        MyConfig bean = run.getBean(MyConfig.class);
        System.out.println("配置类也是组件：" + bean);
    }
}

@Configuration(proxyBeanMethods = false) //改成 false
public class MyConfig {
    @Bean("user1") //给容器中添加组件。以方法名作为组件的id。返回类型就是组件类型。返回的值，就是组件在容器中的实例
    public User user01(){
        return new User("pingguo", 20);
    }
    @Bean("pet1")
    public Pet tomcatPet(){
        return new Pet("tomcat");
    }
}

@SpringBootApplication(scanBasePackages = "com.pingguo")
public class MainApplication {
    public static void main(String[] args) {
        // 返回IOC容器
        final ConfigurableApplicationContext run = SpringApplication.run(MainApplication.class, args);
        // 查看容器里的组件
        final String[] beanDefinitionNames = run.getBeanDefinitionNames();
        for (String name: beanDefinitionNames) {
            System.out.println(name);
        }
        // 从容器中获取组件
        MyConfig bean = run.getBean(MyConfig.class);
        System.out.println("配置类也是组件：" + bean);
        User user1 = bean.user01();
        User user2 = bean.user01();
        System.out.println(user1 == user2);
    }
}

public class User {
    private String name;
    private Integer age;
    private Pet pet;
... ...

public class Pet {
    private String name;
... ...

@Configuration(proxyBeanMethods = true)
public class MyConfig {
    @Bean("user1") 
    public User user01(){
        User pingguo = new User("pingguo",20);
        pingguo.setPet(tomcatPet());
        return pingguo;
    }
    @Bean("pet1")
    public Pet tomcatPet(){
        return new Pet("tomcat");
    }
}

// 依赖关系
    User user01 = run.getBean("user1", User.class);
    Pet pet1 = run.getBean("pet1", Pet.class);
    System.out.println("依赖：" + (user01.getPet() == pet1));