1. 使用xml配置

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="user" class="com.dake.model.Person">
        <property name="name" value="zhangsan" ></property>
        <property name="age" value="18"></property>
    </bean>
</beans>

2.@configuration + @Bean 注解方式

@Configuration
public class UserConfig{
    @Bean("user")
    public User getUser(){
        return new User("張三",18);
    }
}

3.通過掃描包注解componentScan

@componentScan 可以掃描包下的@Controller @Service @Repository @Component注解叽粹。

4.使用@import批量導(dǎo)入

當(dāng)引入外部包時需要導(dǎo)入多個bean時就要使用@import批量導(dǎo)入

@Configuration
@Import(Role.class)
public class UserConfig{
    @Bean(value = "user")
    public user getUser() {
        return new User("張三", 18);
    }
}

@Import在導(dǎo)入Bean的時候却舀，Bean的名稱是全類名，如果導(dǎo)入多個類的話辆脸，輸入格式是這樣：

@Import({Role.class,Person.class})

除了使用@import注解還可以是實現(xiàn)importSelector接口或ImportBeanDefinitionRegistrar接口

public class MyImportSelector implements ImportSelector {
    @Override
    public String[] selectImports(AnnotationMetadata annotationMetadata) {
        return new String[]{"com.dake.model.User"};
    }

public class MyImportBeanDefinitionRegistrar implements ImportBeanDefinitionRegistrar {
    /**
     * @param annotationMetadata     當(dāng)前類的注解信息
     * @param beanDefinitionRegistry BeanDefinotion注冊類
     */
    @Override
    public void registerBeanDefinitions(AnnotationMetadata annotationMetadata, BeanDefinitionRegistry beanDefinitionRegistry) {
        Set<String> annotationTypes = annotationMetadata.getAnnotationTypes();
        System.out.println("注解類：" + annotationTypes);
 
        //判斷是容器中是否有User
        boolean definition = beanDefinitionRegistry.containsBeanDefinition("com.dake.modle.User");
        if (definition ){
            RootBeanDefinition rootBeanDefinition = new RootBeanDefinition(Role.class);
            //注冊Role 類名字為role
            beanDefinitionRegistry.registerBeanDefinition("role", rootBeanDefinition);
        }
    }
}

5.實現(xiàn)FactoryBean接口

注入的為getObject方法返回值

public class MyBeanFactory implements FactoryBean<User> {

    public User getObject() throws Exception {
        return new User();
    }

    public Class<?> getObjectType() {
        return User.class;
    }

    public boolean isSingleton() {
        return true;
    }
}