实现IOC和Bean容器功能

framework/src/main/java/com/custom/framework/helper/BeanHelper.java

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+package com.custom.framework.helper;
+
+import com.custom.framework.util.ReflectionUtil;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Bean助手类
+ * @author liuyi
+ * @date 2018/10/25
+ */
+public class BeanHelper {
+
+ /**
+ * 定义Bean映射（用于存放Bean类与Bean实例的映射关系）
+ */
+ private static final Map<Class<?>, Object> BEAN_MAP = new HashMap<Class<?>, Object>();
+
+ static {
+ Set<Class<?>> beanClassSet = ClassHelper.getBeanClassSet();
+ for (Class<?> beanClass : beanClassSet) {
+ Object obj = ReflectionUtil.newInstance(beanClass);
+ BEAN_MAP.put(beanClass, obj);
+ }
+ }
+
+ /**
+ * 获取Bean映射
+ * @return
+ */
+ public static Map<Class<?>, Object> getBeanMap() {
+ return BEAN_MAP;
+ }
+
+ /**
+ * 获取Bean实例
+ * @param cls
+ * @param <T>
+ * @return
+ */
+ public static <T> T getBean(Class<T> cls) {
+ if (!BEAN_MAP.containsKey(cls)) {
+ throw new RuntimeException("can not get bean by class: " + cls);
+ }
+ return (T)BEAN_MAP.get(cls);
+ }
+
+}

framework/src/main/java/com/custom/framework/helper/IocHelper.java

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+package com.custom.framework.helper;
+
+
+import com.custom.framework.annotation.Inject;
+import com.custom.framework.util.ArrayUtil;
+import com.custom.framework.util.CollectionUtil;
+import com.custom.framework.util.ReflectionUtil;
+
+import java.lang.reflect.Field;
+import java.util.Map;
+
+/**
+ * 依赖注入助手类
+ * @author liuyi
+ * @date 2018/10/27
+ */
+public class IocHelper {
+
+ static {
+ //获取所有的Bean类与Bean实例之间的映射关系（简称BeanMap）
+ Map<Class<?>, Object> beanMap = BeanHelper.getBeanMap();
+ if (CollectionUtil.isNotEmpty(beanMap)) {
+ //遍历BeanMap
+ for (Map.Entry<Class<?>, Object> beanEntry : beanMap.entrySet()) {
+ //从BeanMap中获取Bean类与Bean实例
+ Class<?> beanClass = beanEntry.getKey();
+ Object beanInstance = beanEntry.getValue();
+ //获取Bean类定义的所有成员变量(简称Bean Field)
+ Field[] beanFields = beanClass.getDeclaredFields();
+ if (ArrayUtil.isNotEmpty(beanFields)) {
+ //遍历Bean Field
+ for (Field beanField : beanFields) {
+ //判断当前Bean Field 是否带有Inject注解
+ if (beanField.isAnnotationPresent(Inject.class)) {
+ //在Bean Map中获取Bean Field对应的实例
+ Class<?> beanFieldClass = beanField.getType();
+ Object beanFieldInstance = beanMap.get(beanFieldClass);
+ if (beanFieldInstance != null) {
+ //通过反射初始化 BeanField的值
+ ReflectionUtil.setField(beanInstance, beanField, beanFieldInstance);
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+}

framework/src/main/java/com/custom/framework/util/ArrayUtil.java

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+package com.custom.framework.util;
+
+import org.apache.commons.lang3.ArrayUtils;
+
+/**
+ * 数组工具类
+ * @author liuyi
+ * @date 2018/10/27
+ */
+public class ArrayUtil {
+ /**
+ * 判断数组是否非空
+ * @param array
+ * @return
+ */
+ public static boolean isNotEmpty(Object[] array) {
+ return !ArrayUtils.isEmpty(array);
+ }
+
+ /**
+ * 判断数组是否为空
+ * @param array
+ * @return
+ */
+ public static boolean isEmpty(Object[] array) {
+ return ArrayUtil.isEmpty(array);
+ }
+}

framework/src/main/java/com/custom/framework/util/CollectionUtil.java

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+package com.custom.framework.util;
+
+import java.util.Map;
+/**
+ * @author liuyi
+ * @date 2018/10/27
+ */
+public class CollectionUtil {
+
+ public static boolean isNotEmpty(Map<Class<?>, Object> map) {
+ if (map == null || map.size() == 0) {
+ return false;
+ }
+ return true;
+ }
+}

framework/src/main/java/com/custom/framework/util/ReflectionUtil.java

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+package com.custom.framework.util;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+
+/**
+ * 反射工具类
+ * @author liuyi
+ * @date 2018/10/25
+ */
+public final class ReflectionUtil {
+
+ private static final Logger LOGGER = LoggerFactory.getLogger(ReflectionUtil.class);
+
+ /**
+ * 创建实例
+ */
+ public static Object newInstance(Class<?> cls) {
+ Object instance;
+ try {
+ instance = cls.newInstance();
+ } catch (Exception e) {
+ LOGGER.error("new instance failure", e);
+ throw new RuntimeException(e);
+ }
+ return instance;
+ }
+
+ /**
+ * 调用方法
+ */
+ public static Object invokeMethod(Object obj, Method method, Object...args) {
+ Object result;
+ try {
+ method.setAccessible(true);
+ result = method.invoke(obj, args);
+ } catch (Exception e) {
+ LOGGER.error("invoke method failure", e);
+ throw new RuntimeException(e);
+ }
+ return result;
+ }
+ /**
+ * 设置成员变量的值
+ */
+ public static void setField(Object obj, Field field, Object value) {
+ try {
+ field.setAccessible(true);
+ field.set(obj, value);
+ } catch(Exception e) {
+ LOGGER.error("set field failure", e);
+ throw new RuntimeException(e);
+ }
+ }
+}