@Configuration容器中注册组件

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import boot.bean.Stu; import boot.bean.User; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration;   /**  * 1.配置类里面使用@Bean标注在方法上给容器注册组件，默认也是单实例  * 2.配置类本身也是组件  * 3.@Configuration中的属性：proxyBeanMethods，设为true：@Configuration(proxyBeanMethods=true),外部无论对配置类中的  * 这个组件注册方法调用多少次都返回之前注册容器中的单例对象。如果为false，则每次调用新new一个对象  */ @Configuration//告诉springboot这是一个配置类 public class MyConfig {       @Bean//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("张三",20);     }       @Bean("tom")//命名组件名为“tom”     public Stu stu01(){         return new Stu("汤姆");     } }

 

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public class Stu {     private String name;       public Stu(String name) {         this.name = name;     }       public String getName() {         return name;     }       public void setName(String name) {         this.name = name;     }       @Override     public String toString() {         return "Stu{" +                 "name='" + name + '\'' +                 '}';     } }

　　

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public class User {     private String name;     private int age;       public User(String name, int age) {         this.name = name;         this.age = age;     }       public String getName() {         return name;     }       public void setName(String name) {         this.name = name;     }       public int getAge() {         return age;     }       public void setAge(int age) {         this.age = age;     }       @Override     public String toString() {         return "User{" +                 "name='" + name + '\'' +                 ", age=" + age +                 '}';     } }

　　

　

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@SpringBootApplication public class MainApplication {     public static void main(String[] args) {         //返回IOC容器         ConfigurableApplicationContext run = SpringApplication.run(MainApplication.class, args);         //查看容器里面的组件         String[] names = run.getBeanDefinitionNames();         /*for (String name : names) {             System.out.println(name);         }*/         //从容器中获取组件         Stu tom1 = run.getBean("tom", Stu.class);         tom1.setName("杰瑞");         Stu tom2 = run.getBean("tom", Stu.class);         System.out.println(tom2);//Stu{name='杰瑞'}     } }