一、Spring容器继承图

二、往IoC容器添加bean方式

2.1 基于xml定义Bean

2.1.1 在工程的resources目录下新建文件beans.xml，配置如下代码：

<?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="person" class="com.mxf.ioc.base.service.People"></bean>
</beans>

2.1.2 创建main方法执行如下代码：

@SpringBootApplication
public class MainApplication {
    public static void main(String[] args) {
        ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("beans.xml");
        System.out.println(applicationContext.getBean("person"));
    }

2.1.3 执行结果如下：

2.2 基于配置类定义Bean

2.2.1 在工程下新建MainConfig类，代码如下：

@Configuration
public class MainConfig {
    @Bean
    public People people(){
        return new People();
    }
}

bean的默认名称是方法名，也可以通过@Bean(value="bean name")指定。

2.2.2 创建Main方法执行如下代码：

public class MainApplication {

    public static void main(String[] args) {
        AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(MainConfig.class);
        System.out.println(applicationContext.getBean("people"));
    }

2.2.3 执行结果如下：

2.3 通过@ComponentScan注解来进行包扫描

需要和@Controller @Service @Component @Respository注解组合

@ComponentScan(basePackages = {"com.mxf.ioc"},
excludeFilters = {@ComponentScan.Filter(type = FilterType.ANNOTATION, value = {Controller.class}),
includeFilters = {@ComponentScan.Filter(type = FilterType.ANNOTATION, value = {Service.class}),
@ComponentScan.Filter(type = FilterType.CUSTOM, value = {CustomFilterType.class})},
useDefaultFilters = false)

excludeFilters排除Controller注解，includeFilters包含注解，若使用includeFilters或者FilterType.CUSTOM时，需设置useDefaultFilters = false。

2.3.1 自定义FilterFilter

public class CustomFilterType implements TypeFilter {

    public boolean match(MetadataReader metadataReader, MetadataReaderFactory metadataReaderFactory) throws IOException {
        AnnotatedTypeMetadata annotatedTypeMetadata = metadataReader.getAnnotationMetadata();
        Resource resource = metadataReader.getResource();
        ClassMetadata classMetadata = metadataReader.getClassMetadata();
        if(classMetadata.getClassName().contains("Controller")){
            return true;
        }
        return false;
    }
}

2.4 通过@Import来导入bean

@Import(value = {StudentImportSelector.class, com.mxf.ioc.base.Person.class, StudentBeanDefinitionRegister.class})
@Configuration
public class MainConfig {
}

2.5 通过ImportSelector

public class StudentImportSelector implements ImportSelector {
    public String[] selectImports(AnnotationMetadata annotationMetadata) {
        return new String[]{"com.mxf.ioc.base.service.TestService"};
    }
}

2.6 通过ImportBeanDefinitionRegistrar

public class StudentBeanDefinitionRegister implements ImportBeanDefinitionRegistrar {

    public void registerBeanDefinitions(AnnotationMetadata annotationMetadata, BeanDefinitionRegistry beanDefinitionRegistry) {
        // 创建一个bean对象
        RootBeanDefinition beanDefinition = new RootBeanDefinition(TestController.class);
        // 把bean对象注册到容器中　
        beanDefinitionRegistry.registerBeanDefinition("testController", beanDefinition);

    }
}

2.7 通过FacotryBean

public class StudentFactoryBean implements FactoryBean<Student> {
    public Student getObject() throws Exception {
        return new Student();
    }

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

    public boolean isSingleton() {
        return true;
    }
}

三、 Spring的生命周期

bean的实例化、初始化、销毁等完整流程。

2.1 init和destroy方法

@Configuration
public class MainConfig {
    @Bean(initMethod = "init", destroyMethod = "destroy")
    public People people(){
        return new People();
    }
}

2.2 实现InitializingBean和DisposableBean

public class People implements InitializingBean, DisposableBean {
    @Override
    public void afterPropertiesSet() throws Exception {  
    }
    @Override
    public void destroy() throws Exception {  
    }
}

2.3 实现@PostConstruct 和@PreDestory

public class People{
    @PostConstruct
    public void init(){
    }
    
    @PreDestroy
    public void destroy(){
    }
}

2.4 通过BeanPostProcessor

@Component
public class CustomBeanPostProcessor implements BeanPostProcessor {
    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        return bean;
    }
    
    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        return bean;
    }
}

2.5 通过@Value +@PropertySource来给组件赋值

2.5.1 在resources目录下新建person.properties文件

person.lastName=jerry

2.5.2 指定外部文件位置

@PropertySource(value = {"classpath:person.properties"})
@Configuration
public class MainConfig {
       @Bean
        public Person1 person1(){
                return new Person1();
        }
}

```
@Data
public class Person1 {

    @Value("tom")
    private String firstName;

    @Value("#{28-8}")
    private Integer age;

    @Value("${person.lastName}")
    private String lastName;

}
```