手动实现java springboot依赖注入

package org.example; import java.lang.reflect.Constructor; import java.lang.reflect.Field; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.util.HashMap; import java.util.Map; // 容器类，用于管理对象实例 class MyContainer { private Map<Class<?>, Object> instances = new HashMap<>(); private Map<Class<?>, Boolean> inCreation = new HashMap<>(); // 自动扫描注册 public void registerClass(Class<?> clazz) throws IllegalAccessException, InstantiationException, InvocationTargetException { if (instances.containsKey(clazz)) { return; } inCreation.put(clazz, true); Object instance = createInstance(clazz); instances.put(clazz, instance); inCreation.remove(clazz); injectDependencies(instance); } // 创建实例 private Object createInstance(Class<?> clazz) throws IllegalAccessException, InstantiationException, InvocationTargetException { Constructor<?>[] constructors = clazz.getDeclaredConstructors(); for (Constructor<?> constructor : constructors) { if (constructor.isAnnotationPresent(MyAutowired.class)) { Class<?>[] parameterTypes = constructor.getParameterTypes(); Object[] parameters = new Object[parameterTypes.length]; for (int i = 0; i < parameterTypes.length; i++) { Class<?> paramType = parameterTypes[i]; if (inCreation.containsKey(paramType) && inCreation.get(paramType)) { throw new RuntimeException("检测到循环依赖: " + clazz.getName() + " -> " + paramType.getName()); } parameters[i] = getInstance(paramType); } return constructor.newInstance(parameters); } } return clazz.newInstance(); } // 获取对象实例 public Object getInstance(Class<?> clazz) throws IllegalAccessException, InstantiationException, InvocationTargetException { if (!instances.containsKey(clazz)) { registerClass(clazz); } return instances.get(clazz); } // 实现依赖注入 public void injectDependencies(Object target) throws IllegalAccessException, InvocationTargetException, InstantiationException { Class<?> clazz = target.getClass(); // 字段注入 Field[] fields = clazz.getDeclaredFields(); for (Field field : fields) { if (field.isAnnotationPresent(MyAutowired.class)) { field.setAccessible(true); Class<?> fieldType = field.getType(); Object dependency = getInstance(fieldType); if (dependency == null) { throw new RuntimeException("未找到字段的依赖项: " + field.getName() + " 在类: " + clazz.getName()); } field.set(target, dependency); } } // 方法注入 Method[] methods = clazz.getDeclaredMethods(); for (Method method : methods) { if (method.isAnnotationPresent(MyAutowired.class)) { method.setAccessible(true); Class<?>[] parameterTypes = method.getParameterTypes(); Object[] parameters = new Object[parameterTypes.length]; for (int i = 0; i < parameterTypes.length; i++) { Class<?> paramType = parameterTypes[i]; Object dependency = getInstance(paramType); if (dependency == null) { throw new RuntimeException("未找到参数的依赖项: " + paramType.getName() + " 在方法: " + method.getName() + " 类: " + clazz.getName()); } parameters[i] = dependency; } method.invoke(target, parameters); } } } }