3.1 IOC - BeanFactory

主要接口

分析DefaultListableBeanFactory类的层次结构，包含了ioc容器中的主要的接口和实现类

DefaultListableBeanFactory.png

一、主要接口

BeanFactory

• 依赖查找

  • 通过名称、类型、构造器参数查找bean

  • 查找延迟初始化bean

  • 查找bean的方式为“拉模式”（依赖注入为“推模式”）

• 判断bean名称和类型是否匹配

• 通过名称查询bean的类型

• 定义初始化方法标准顺序

  1. BeanNameAware's setBeanName
  2. BeanClassLoaderAware's setBeanClassLoader
  3. BeanFactoryAware's setBeanFactory
  4. EnvironmentAware's setEnvironment
  5. EmbeddedValueResolverAware's setEmbeddedValueResolver
  6. ResourceLoaderAware's setResourceLoader (only applicable when running in an application context)
  7. ApplicationEventPublisherAware's setApplicationEventPublisher (only applicable when running in an application context)
  8. MessageSourceAware's setMessageSource (only applicable when running in an application context)
  9. ApplicationContextAware's setApplicationContext (only applicable when running in an application context)
  10. ServletContextAware's setServletContext (only applicable when running in a web application context)
  11. postProcessBeforeInitialization methods of BeanPostProcessors
  12. InitializingBean's afterPropertiesSet
  13. a custom init-method definition
  14. postProcessAfterInitialization methods of BeanPostProcessors

• 定义关闭容器时销毁方法的顺序

  On shutdown of a bean factory, the following lifecycle methods apply:

  1. postProcessBeforeDestruction methods of DestructionAwareBeanPostProcessors
  2. DisposableBean's destroy
  3. a custom destroy-method definition

示例：

private static void s3_21() {
    DefaultListableBeanFactory defaultListableBeanFactory = new DefaultListableBeanFactory();
    final XmlBeanDefinitionReader xmlBeanDefinitionReader = new XmlBeanDefinitionReader(defaultListableBeanFactory);
    xmlBeanDefinitionReader.loadBeanDefinitions("s3/s3-bean.xml");

    BeanFactory beanFactory = defaultListableBeanFactory;

    // 1. 依赖查找
    // 通过名称查找
    Object bean1 = beanFactory.getBean("t5Service");
    // 通过类型查找
    T5Service t5Service1 = beanFactory.getBean(T5Service.class);
    // 通过名称和类型查找
    T5Service t5Service2 = beanFactory.getBean("t5Service", T5Service.class);
    // 通过名称和构造器参数查找（单例和原型不同，单例只有第一次实例化会使用构造器参数）
    Object bean2 = beanFactory.getBean("t5Service", "test");
    // 通过类型和构造器参数查找（单例和原型不同，单例只有第一次实例化会使用构造器参数）
    T5Service t5Service3 = beanFactory.getBean(T5Service.class, "test");

    // 延迟查找
    ObjectProvider<T5Service> beanProvider = beanFactory.getBeanProvider(T5Service.class);

    // 2. 类型匹配
    final boolean isTypeMatch1 = beanFactory.isTypeMatch("t5Service", T5Service.class);
    final boolean isTypeMatch2 = beanFactory.isTypeMatch("t5Service", ResolvableType.forType(T5Service.class));

    // 3. 查询bean的类型
    final Class<?> beanType = beanFactory.getType("t5Service");
}

测试初始化、销毁方法顺序

private static void s3_22() {
    DefaultListableBeanFactory defaultListableBeanFactory = new DefaultListableBeanFactory();
    final XmlBeanDefinitionReader xmlBeanDefinitionReader = new XmlBeanDefinitionReader(defaultListableBeanFactory);
    xmlBeanDefinitionReader.loadBeanDefinitions("s3/s3-bean.xml");

    // 注册通用注解处理器（包括初始化、销毁方法注解）
    final CommonAnnotationBeanPostProcessor commonAnnotationBeanPostProcessor = new CommonAnnotationBeanPostProcessor();
    commonAnnotationBeanPostProcessor.setBeanFactory(defaultListableBeanFactory);
    defaultListableBeanFactory.addBeanPostProcessor(commonAnnotationBeanPostProcessor);

    // 注册自定义的BeanPostProcess
    defaultListableBeanFactory.addBeanPostProcessor(new CusBeanPostProcess());

    // 创建bean
    T5Service t5Service = defaultListableBeanFactory.getBean(T5Service.class);

    // 销毁单例
    defaultListableBeanFactory.destroySingletons();
}

自定义处理器

@Slf4j
public class CusBeanPostProcess implements BeanPostProcessor {
    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        printNo();
        return BeanPostProcessor.super.postProcessBeforeInitialization(bean, beanName);
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        printNo();
        return BeanPostProcessor.super.postProcessAfterInitialization(bean, beanName);
    }

    private void printNo() {
        final StackTraceElement stackTrace = new Throwable().getStackTrace()[1];
        String name = stackTrace.getClassName() + "=>" + stackTrace.getMethodName();
        log.info("方法名称【{}】，no=【{}】", name, NO.addAndGet(1));
    }
}

定义测试bean

@Slf4j
public class T5Service implements
        BeanNameAware, BeanClassLoaderAware, BeanFactoryAware, EmbeddedValueResolverAware,
        InitializingBean, DisposableBean {

    public static final AtomicInteger NO = new AtomicInteger(0);

    private String data;

    public T5Service() {
        printNo();
    }

    public T5Service(String data) {
        this.data = data;
        log.info("带参构造器");
        printNo();
    }

    public String getData() {
        return data;
    }

    public void setData(String data) {
        this.data = data;
    }

    public void doSomething() {
        log.info("name is " + getData());
    }

    @PostConstruct
    public void initAnno() {
        printNo();
    }

    public void initXml() {
        printNo();
    }

    @PreDestroy
    public void destroyAnno() {
        printNo();
    }

    public void destroyXml() {
        printNo();
    }

    private void printNo() {
        final StackTraceElement stackTrace = new Throwable().getStackTrace()[1];
        String name = stackTrace.getClassName() + "=>" + stackTrace.getMethodName();
        log.info("方法名称【{}】，no=【{}】", name, NO.addAndGet(1));
    }

    @Override
    public void setBeanClassLoader(ClassLoader classLoader) {
        printNo();
    }

    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        printNo();
    }

    @Override
    public void setBeanName(String name) {
        printNo();
    }

    @Override
    public void destroy() throws Exception {
        printNo();
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        printNo();
    }

    @Override
    public void setEmbeddedValueResolver(StringValueResolver resolver) {
        printNo();
    }
}

xml配置bean的元数据

<?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 name="t5Service" class="org.example.service.s3.T5Service" init-method="destroyXml" destroy-method="destroyXml"/>
</beans>

HierarchicalBeanFactory

接口增加了对层次结构的支持

• 获取父容器
• 判断当前工厂是否包含bean，不查询父工厂

示例：

private static void t3_31() {
    // 父容器
    DefaultListableBeanFactory parentBeanFactory = new DefaultListableBeanFactory();
    final XmlBeanDefinitionReader xmlBeanDefinitionReader = new XmlBeanDefinitionReader(parentBeanFactory);
    xmlBeanDefinitionReader.loadBeanDefinitions("s3/s3-parent-bean.xml");

    // 当前容器
    DefaultListableBeanFactory defaultListableBeanFactory = new DefaultListableBeanFactory();
    final XmlBeanDefinitionReader xmlBeanDefinitionReader1 = new XmlBeanDefinitionReader(defaultListableBeanFactory);
    xmlBeanDefinitionReader1.loadBeanDefinitions("s3/s3-bean.xml");

    // 设置父容器
    defaultListableBeanFactory.setParentBeanFactory(parentBeanFactory);

    // 测试方法
    HierarchicalBeanFactory hierarchicalBeanFactory = defaultListableBeanFactory;
    final boolean isContain = hierarchicalBeanFactory.containsBean("t4Service");
    final boolean isContain1 = hierarchicalBeanFactory.containsLocalBean("t4Service");
    log.info("[{}-{}]", isContain, isContain1);
}

ListableBeanFactory

可列举的

• 通过类型、注解获取bean名称列表（不考虑层次结构）

• 通过类型、注解获取所有bean（不考虑层次结构）

• BeanFactoryUtils

ConfigurableBeanFactory

增加设置、修改beanFactory的方法

• 注册外部单例bean，继承SingletonBeanRegistry接口
• 设置bean classloader、bean表达式解析器、类型转换器、嵌入的值解析器、bean后置处理器
• 注册scope、别名值解析器、依赖bean
• 注册别名
• 销毁bean

示例：

private static void s3_41() {
    DefaultListableBeanFactory defaultListableBeanFactory = new DefaultListableBeanFactory();
    final XmlBeanDefinitionReader xmlBeanDefinitionReader = new XmlBeanDefinitionReader(defaultListableBeanFactory);
    xmlBeanDefinitionReader.loadBeanDefinitions("s3/s3-bean.xml");

    // 注册通用注解处理器（包括初始化、销毁方法注解）
    final CommonAnnotationBeanPostProcessor commonAnnotationBeanPostProcessor = new CommonAnnotationBeanPostProcessor();
    commonAnnotationBeanPostProcessor.setBeanFactory(defaultListableBeanFactory);
    defaultListableBeanFactory.addBeanPostProcessor(commonAnnotationBeanPostProcessor);
    // 注册自定义的BeanPostProcess
    defaultListableBeanFactory.addBeanPostProcessor(new CusBeanPostProcess());

    ConfigurableBeanFactory configurableBeanFactory = defaultListableBeanFactory;

    // 创建bean
    T5Service t5Service = configurableBeanFactory.getBean(T5Service.class);

    log.info("====================================================");
    // 销毁bean，并不会清除单例缓存，只是调用销毁方法
    configurableBeanFactory.destroyBean("t5Service", t5Service);
    log.info("====================================================");

    // 销毁所有单例bean
    configurableBeanFactory.destroySingletons();
}

AutowireCapableBeanFactory

• 增加创建和填充外部bean实例的方法

  • createBean
  • autowireBean
  • configureBean

• 增加对bean生命周期进行细粒度控制的专用方法

• 增加解析注入点的方法

  • resolveNamedBean
  • resolveBeanByName
  • resolveDependency

示例：

private static void s3_51() {
    DefaultListableBeanFactory defaultListableBeanFactory = buildBeanFactory();
    registerBeanPostProcessor(defaultListableBeanFactory);

    AutowireCapableBeanFactory autowireCapableBeanFactory = defaultListableBeanFactory;

    // Ioc容器中不存在T6Service类的信息
    // 创建和填充外部bean实例
    T6Service t6Service1 = autowireCapableBeanFactory.createBean(T6Service.class);
    log.info("[{}]", t6Service1);

    // 处理被注解的属性和方法
    T6Service t6Service2 = new T6Service();
    autowireCapableBeanFactory.autowireBean(t6Service2);
    log.info("[{}]", t6Service2);

    // 使用Ioc中可用的bean元数据，来配置外部bean
    T6Service t6Service3 = new T6Service();
    final Object t6Service4 = autowireCapableBeanFactory.configureBean(t6Service3, "t5Service");
    log.info("[{}]", t6Service3);
}

private static void s3_52() {
    DefaultListableBeanFactory defaultListableBeanFactory = buildBeanFactory();
    registerBeanPostProcessor(defaultListableBeanFactory);

    AutowireCapableBeanFactory autowireCapableBeanFactory = defaultListableBeanFactory;

    // Ioc容器中不存在T6Service类的信息
    // 创建和填充外部bean实例；
    // 对javabeans属性根据类型查找依赖进行注入；
    // 若检查依赖，依赖不存在，则创建失败
    Object t6Service1 = autowireCapableBeanFactory.createBean(T6Service.class, AutowireCapableBeanFactory.AUTOWIRE_BY_TYPE, false);
    log.info("[{}]", t6Service1);

    // 对存在Set方法属性进行依赖注入
    final Object t6Service2 = autowireCapableBeanFactory.autowire(T6Service.class, AutowireCapableBeanFactory.AUTOWIRE_BY_TYPE, false);
    log.info("[{}]", t6Service2);

    // 对外部bean的属性进行依赖注入
    T6Service t6Service3 = new T6Service();
    autowireCapableBeanFactory.autowireBeanProperties(t6Service3, AutowireCapableBeanFactory.AUTOWIRE_BY_TYPE, false);
    log.info("[{}]", t6Service3);

    // 使用Ioc中可用的bean元数据，来配置外部bean
    final T6Service t6Service4 = new T6Service();
    autowireCapableBeanFactory.applyBeanPropertyValues(t6Service4, "t5Service");
    log.info("[{}]", t6Service4);
}

private static void s3_53() throws Exception {
    DefaultListableBeanFactory defaultListableBeanFactory = buildBeanFactory();
    registerBeanPostProcessor(defaultListableBeanFactory);

    AutowireCapableBeanFactory autowireCapableBeanFactory = defaultListableBeanFactory;

    final DependencyDescriptor dependencyDescriptor = new DependencyDescriptor(T6Service.class.getDeclaredField("t4Service1"), true);
    final Object t4Service = autowireCapableBeanFactory.resolveBeanByName("t4Service", dependencyDescriptor);
    log.info("[{}]", t4Service);

    // 解析依赖
    Object dependency = autowireCapableBeanFactory.resolveDependency(dependencyDescriptor, null);
    log.info("[{}]", dependency);
}

ConfigurableListableBeanFactory

可列举的、可配置的

• 支持自动注入模式下，忽略特定javabean属性的注入
• 注册外部（非正常注册IoC的bean）依赖
• 判断某依赖是否有注入其他bean的能力
• 通过名称获取BeanDefinition
• 支持预先实例化所有单例bean

示例：

private static void s3_61() {
    DefaultListableBeanFactory defaultListableBeanFactory = buildBeanFactory();
    registerBeanPostProcessor(defaultListableBeanFactory);

    ConfigurableListableBeanFactory configurableListableBeanFactory = defaultListableBeanFactory;

    final T6Service t6Service1 = new T6Service();
    configurableListableBeanFactory.autowireBeanProperties(t6Service1, AutowireCapableBeanFactory.AUTOWIRE_BY_TYPE, false);

    // 通过构造器参数、javabean属性类型、javabean属性名称自动注入时，忽略的依赖类型
    configurableListableBeanFactory.ignoreDependencyType(T4Service.class);
    // 通过javabean属性类型、javabean属性名称自动注入时，忽略的接口中的属性
    // 如下：该接口setBeanFactory()即属性：beanFactory
    configurableListableBeanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class);

    final T6Service t6Service2 = new T6Service();
    configurableListableBeanFactory.autowireBeanProperties(t6Service2, AutowireCapableBeanFactory.AUTOWIRE_BY_TYPE, true);
    log.info("[{}]-[{}]", t6Service1, t6Service2);

    // 注册可解析的依赖，依赖注入时可注入其他bean
    configurableListableBeanFactory.registerResolvableDependency(T6Service.class, t6Service2);

    // 实例化所有单例
    configurableListableBeanFactory.preInstantiateSingletons();
}

二、主要类

AbstractBeanFactory 模板类

AbstractAutowireCapableBeanFactory 模板类

DefaultListableBeanFactory 完整实现类