implement lightweight IOC/DI framework
- Add annotation system (@Component, @Service, @Configuration, @Bean, @Inject, @Qualifier, @Primary, @Scope, @PostConstruct, @Import, @TimiInjectApplication) - Implement BeanContext for managing bean instances and definitions - Implement BeanScanner for component scanning (file system and jar) - Implement BeanFactory with constructor injection and lifecycle support - Support @Configuration and @Bean factory methods - Support @Qualifier and @Primary for multi-implementation - Support @Scope (singleton/prototype) - Support @PostConstruct lifecycle callback - Support @Import and Module extension - Add circular dependency detection - Add dependency graph export - Add demo and test cases Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
This commit is contained in:
Timi
216
src/main/java/com/imyeyu/inject/BeanFactory.java
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216
src/main/java/com/imyeyu/inject/BeanFactory.java
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package com.imyeyu.inject;
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import com.imyeyu.inject.annotation.Qualifier;
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import com.imyeyu.inject.annotation.ScopeType;
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import org.slf4j.Logger;
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import org.slf4j.LoggerFactory;
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import java.lang.reflect.Constructor;
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import java.lang.reflect.Method;
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import java.lang.reflect.Parameter;
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import java.util.*;
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/**
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* Bean 工厂，负责创建和管理 Bean 实例
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*
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* @author 夜雨
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*/
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public class BeanFactory {
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private static final Logger log = LoggerFactory.getLogger(BeanFactory.class);
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private final BeanContext context;
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private final Set<String> creating = new HashSet<>();
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public BeanFactory(BeanContext context) {
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this.context = context;
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}
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/**
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* 获取 Bean 实例（按名称）
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*/
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public Object getBean(String name) {
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BeanDefinition definition = context.getDefinition(name);
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if (definition == null) {
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throw new InjectException("No bean definition found for name: " + name);
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}
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if (definition.getScope() == ScopeType.SINGLETON) {
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Object singleton = context.getSingleton(name);
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if (singleton != null) {
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return singleton;
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}
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}
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return createBean(definition);
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}
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/**
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* 获取 Bean 实例（按类型）
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*/
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@SuppressWarnings("unchecked")
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public <T> T getBean(Class<T> type) {
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List<String> candidates = context.getBeanNamesByType(type);
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if (candidates.isEmpty()) {
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throw new InjectException("No bean found for type: " + type.getName());
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}
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if (candidates.size() == 1) {
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return (T) getBean(candidates.get(0));
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}
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String primaryBean = findPrimaryBean(candidates);
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if (primaryBean != null) {
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return (T) getBean(primaryBean);
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}
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throw new InjectException("Multiple beans found for type " + type.getName() +
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": " + candidates + ". Use @Qualifier or @Primary to specify which one to inject");
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}
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/**
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* 获取 Bean 实例（按名称和类型）
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*/
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@SuppressWarnings("unchecked")
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public <T> T getBean(String name, Class<T> type) {
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Object bean = getBean(name);
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if (!type.isInstance(bean)) {
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throw new InjectException("Bean '" + name + "' is not of type " + type.getName());
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}
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return (T) bean;
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}
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private Object createBean(BeanDefinition definition) {
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String name = definition.getName();
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if (creating.contains(name)) {
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throw new InjectException("Circular dependency detected: " + name +
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" (creation chain: " + creating + ")");
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}
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creating.add(name);
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try {
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Object instance;
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if (definition.isFactoryBean()) {
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instance = createBeanFromFactoryMethod(definition);
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} else {
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instance = createBeanFromConstructor(definition);
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}
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if (definition.getScope() == ScopeType.SINGLETON) {
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context.setSingleton(name, instance);
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}
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invokePostConstruct(instance, definition);
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log.debug("Created bean: {} ({})", name, definition.getType().getName());
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return instance;
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} finally {
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creating.remove(name);
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}
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}
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private Object createBeanFromConstructor(BeanDefinition definition) {
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Constructor<?> constructor = definition.getConstructor();
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constructor.setAccessible(true);
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Parameter[] parameters = constructor.getParameters();
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Object[] args = new Object[parameters.length];
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for (int i = 0; i < parameters.length; i++) {
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args[i] = resolveDependency(parameters[i]);
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}
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try {
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return constructor.newInstance(args);
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} catch (Exception e) {
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throw new InjectException("Failed to instantiate bean: " + definition.getName(), e);
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}
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}
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private Object createBeanFromFactoryMethod(BeanDefinition definition) {
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Method factoryMethod = definition.getFactoryMethod();
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factoryMethod.setAccessible(true);
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String configBeanName = extractConfigBeanName(factoryMethod.getDeclaringClass());
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Object configInstance = getBean(configBeanName);
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Parameter[] parameters = factoryMethod.getParameters();
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Object[] args = new Object[parameters.length];
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for (int i = 0; i < parameters.length; i++) {
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args[i] = resolveDependency(parameters[i]);
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}
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try {
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Object result = factoryMethod.invoke(configInstance, args);
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if (result == null) {
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throw new InjectException("@Bean method returned null: " + factoryMethod.getName());
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}
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return result;
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} catch (Exception e) {
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throw new InjectException("Failed to invoke @Bean method: " + factoryMethod.getName(), e);
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}
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}
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private Object resolveDependency(Parameter parameter) {
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Qualifier qualifier = parameter.getAnnotation(Qualifier.class);
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if (qualifier != null) {
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return getBean(qualifier.value());
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}
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Class<?> type = parameter.getType();
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return getBean(type);
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}
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private void invokePostConstruct(Object instance, BeanDefinition definition) {
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Method postConstruct = definition.getPostConstruct();
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if (postConstruct == null) {
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return;
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}
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postConstruct.setAccessible(true);
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try {
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postConstruct.invoke(instance);
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} catch (Exception e) {
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throw new InjectException("Failed to invoke @PostConstruct method: " +
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postConstruct.getName(), e);
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}
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}
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private String findPrimaryBean(List<String> candidates) {
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String primaryBean = null;
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for (String name : candidates) {
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BeanDefinition definition = context.getDefinition(name);
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if (definition.isPrimary()) {
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if (primaryBean != null) {
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throw new InjectException("Multiple @Primary beans found: " + primaryBean + ", " + name);
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}
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primaryBean = name;
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}
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}
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return primaryBean;
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}
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private String extractConfigBeanName(Class<?> configClass) {
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String simpleName = configClass.getSimpleName();
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return Character.toLowerCase(simpleName.charAt(0)) + simpleName.substring(1);
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}
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/**
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* 初始化所有单例 Bean
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*/
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public void initializeSingletons() {
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for (BeanDefinition definition : context.getAllDefinitions()) {
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if (definition.getScope() == ScopeType.SINGLETON) {
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getBean(definition.getName());
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}
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}
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}
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}
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