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Spring核心技术底层实现详解

news 来源：原创 2025/6/24 7:28:54

第一章：IoC容器底层实现

1.1 核心架构

1.2 Bean生命周期

实例化（InstantiationAwareBeanPostProcessor）
属性填充（populateBean()）
初始化（invokeInitMethods()）
销毁（DisposableBean）

1.3 依赖注入源码

// AbstractAutowireCapableBeanFactory
protected void populateBean(String beanName, RootBeanDefinition mbd, BeanWrapper bw) {// 获取所有属性PropertyValues pvs = mbd.getPropertyValues();if (mbd.getResolvedAutowireMode() == AUTOWIRE_BY_NAME) {autowireByName(beanName, mbd, bw, pvs);}if (mbd.getResolvedAutowireMode() == AUTOWIRE_BY_TYPE) {autowireByType(beanName, mbd, bw, pvs);}
}

第二章：AOP动态代理

2.1 代理模式对比

代理类型	启动速度	性能	限制
JDK动态代理	快	高	需实现接口
CGLIB	慢	中	无法代理final方法

2.2 代理创建流程

2.3 拦截器链执行

// ReflectiveMethodInvocation
public Object proceed() throws Throwable {if (this.currentInterceptorIndex == this.interceptorsAndDynamicMethodMatchers.size() - 1) {return invokeJoinpoint();}// 获取下一个拦截器Object interceptor = interceptorsAndDynamicMethodMatchers.get(++this.currentInterceptorIndex);if (interceptor instanceof MethodInterceptor) {return ((MethodInterceptor) interceptor).invoke(this);}
}

第三章：事务管理

3.1 事务核心类

public interface PlatformTransactionManager {TransactionStatus getTransaction(TransactionDefinition definition);void commit(TransactionStatus status);void rollback(TransactionStatus status);
}// 事务传播行为
public interface TransactionDefinition {int PROPAGATION_REQUIRED = 0;int PROPAGATION_SUPPORTS = 1;//...
}

3.2 事务拦截器

// TransactionInterceptor
public Object invoke(MethodInvocation invocation) throws Throwable {TransactionInfo txInfo = createTransactionIfNecessary();try {Object retVal = invocation.proceed();commitTransactionAfterReturning(txInfo);return retVal;} catch (Throwable ex) {completeTransactionAfterThrowing(txInfo, ex);throw ex;}
}

第四章：Spring MVC

4.1 请求处理流程

4.2 参数绑定原理

// HandlerMethodArgumentResolver
public interface HandlerMethodArgumentResolver {boolean supportsParameter(MethodParameter parameter);Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer,NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception;
}// 实现类示例
public class RequestParamMethodArgumentResolver implements HandlerMethodArgumentResolver {public boolean supportsParameter(MethodParameter parameter) {return parameter.hasParameterAnnotation(RequestParam.class);}
}

第五章：注解驱动原理

5.1 注解处理流程

// ConfigurationClassPostProcessor
public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) {processConfigBeanDefinitions(registry);
}private void processConfigBeanDefinitions(BeanDefinitionRegistry registry) {// 1. 解析@Configuration// 2. 处理@ComponentScan// 3. 处理@Import// 4. 处理@Bean方法
}

5.2 条件注解实现

// OnClassCondition
public ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeMetadata metadata) {String className = (String) metadata.getAnnotationAttributes(ConditionalOnClass.class.getName()).get("value");if (ClassUtils.isPresent(className, context.getClassLoader())) {return ConditionOutcome.match();}return ConditionOutcome.noMatch("Required class not found: " + className);
}

关键图解合集

图1：IoC容器类关系

图2：AOP代理执行流程

图3：事务传播机制

完整示例：自定义BeanPostProcessor

public class CustomBeanPostProcessor implements BeanPostProcessor {@Overridepublic Object postProcessBeforeInitialization(Object bean, String beanName) {System.out.println("初始化前处理: " + beanName);if (bean instanceof UserService) {((UserService) bean).setTag("V1.0");}return bean;}@Overridepublic Object postProcessAfterInitialization(Object bean, String beanName) {System.out.println("初始化后处理: " + beanName);return Proxy.newProxyInstance(bean.getClass().getClassLoader(),bean.getClass().getInterfaces(),(proxy, method, args) -> {System.out.println("代理方法: " + method.getName());return method.invoke(bean, args);});}
}// 配置类
@Configuration
public class AppConfig {@Beanpublic static CustomBeanPostProcessor customBeanPostProcessor() {return new CustomBeanPostProcessor();}
}