1. 本章需要完成的内容

1. 完成AspectListExecutor类的编写
2. 完成AspectWeaver类的编写
3. 完成PointcutLocator类的编写
4. 完成ProxyCreator类的编写

2. 完成PointcutLocator类的编写

2.1 需要完成的代码如下：

package com.wuyiccc.helloframework.aop;import org.aspectj.weaver.tools.PointcutExpression;
import org.aspectj.weaver.tools.PointcutParser;
import org.aspectj.weaver.tools.ShadowMatch;import java.lang.reflect.Method;/*** @author wuyiccc* @date 2020/7/14 9:03* 岂曰无衣，与子同袍~*/
public class PointcutLocator {/*** Pointcut解析器，直接给它赋值上Aspectj的所有表达式，以便支持对众多表达式的解析*/private PointcutParser pointcutParser = PointcutParser.getPointcutParserSupportingSpecifiedPrimitivesAndUsingContextClassloaderForResolution(PointcutParser.getAllSupportedPointcutPrimitives());/*** 表达式解析器*/private PointcutExpression pointcutExpression;public PointcutLocator(String expression) {this.pointcutExpression = pointcutParser.parsePointcutExpression(expression);}/*** 判断传入的Class对象是否是Aspect的目标代理类，即匹配Pointcut表达式(初筛)** @param targetClass 目标类* @return 是否匹配*/public boolean roughMatches(Class<?> targetClass) {return pointcutExpression.couldMatchJoinPointsInType(targetClass); // 只能校验within，对于execution,call,get,set等无法校验的表达式，直接返回true}/*** 判断传入的Method对象是否是Aspect的目标代理方法，即匹配Pointcut表达式(精筛)* @param method* @return*/public boolean accurateMatches(Method method) {ShadowMatch shadowMatch = pointcutExpression.matchesMethodExecution(method);if (shadowMatch.alwaysMatches()) {return true;}return false;}}

2.2 PointcutLocator类相关方法讲解:

3. 完成AspectListExecutor类的编写

3.1 需要完成的代码如下:

package com.wuyiccc.helloframework.aop;import com.wuyiccc.helloframework.aop.aspect.AspectInfo;
import com.wuyiccc.helloframework.util.ValidationUtil;
import lombok.Getter;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;import java.lang.reflect.Method;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;/*** @author wuyiccc* @date 2020/7/14 9:03* 岂曰无衣，与子同袍~*/
public class AspectListExecutor implements MethodInterceptor {private Class<?> targetClass;@Getterprivate List<AspectInfo> sortedAspectInfoList;public AspectListExecutor(Class<?> targetClass, List<AspectInfo> sortedAspectInfoList) {this.targetClass = targetClass;this.sortedAspectInfoList = sortAspectInfoList(sortedAspectInfoList);}/*** 按照order的值进行升序排序，确保Order值小的aspect先被织入** @param aspectInfoList* @return*/private List<AspectInfo> sortAspectInfoList(List<AspectInfo> aspectInfoList) {// 升序排列Collections.sort(aspectInfoList, new Comparator<AspectInfo>() {@Overridepublic int compare(AspectInfo o1, AspectInfo o2) {return o1.getOrderIndex() - o2.getOrderIndex();}});return aspectInfoList;}@Overridepublic Object intercept(Object proxy, Method method, Object[] args, MethodProxy methodProxy) throws Throwable {Object returnValue = null;collectAccurateMatchedAspectList(method);if (ValidationUtil.isEmpty(sortedAspectInfoList)) {return methodProxy.invokeSuper(proxy, args);}// 1. 按照order的顺序升序执行完所有Aspect的before方法invokeBeforeAdvices(method, args);try {// 2. 执行被代理类的方法returnValue = methodProxy.invokeSuper(proxy, args);// 3. 如果被代理方法正常返回，则按照order的顺序降序执行完所有Aspect的afterReturning方法invokeAfterReturningAdvices(method, args, returnValue);} catch (Exception e) {// 4. 如果被代理方法抛出异常，则按照order的顺序降序执行完所有Aspect的afterThrowing方法invokeAfterThrowingAdvices(method, args, e);}return returnValue;}private void collectAccurateMatchedAspectList(Method method) {if (ValidationUtil.isEmpty(sortedAspectInfoList)) {return;}Iterator<AspectInfo> it = sortedAspectInfoList.iterator();while (it.hasNext()) {AspectInfo aspectInfo = it.next();if (!aspectInfo.getPointcutLocator().accurateMatches(method)) {it.remove(); // 需要用Iterator自带的remove，不能用sortedAspectInfoList的remove，否则就会出现并发修改异常}}}private void invokeAfterThrowingAdvices(Method method, Object[] args, Exception e) throws Throwable {for (int i = sortedAspectInfoList.size() - 1; i >= 0; i--) {sortedAspectInfoList.get(i).getAspectObject().afterThrowing(targetClass, method, args, e);}}private void invokeAfterReturningAdvices(Method method, Object[] args, Object returnValue) throws Throwable {for (int i = sortedAspectInfoList.size() - 1; i >= 0; i--) {sortedAspectInfoList.get(i).getAspectObject().afterReturning(targetClass, method, args, returnValue);}}private void invokeBeforeAdvices(Method method, Object[] args) throws Throwable {for (AspectInfo aspectInfo : sortedAspectInfoList) {aspectInfo.getAspectObject().before(targetClass, method, args);}}
}

3.2 AspectListExecutor类相关方法讲解：

4. 完成ProxyCreator类的编写

4.1 需要完成的代码及讲解如下：

5. 完成AspectWeaver类的编写

5.1 需要完成的代码如下：

package org.myframework.aop;import org.myframework.aop.annotation.Aspect;
import org.myframework.aop.annotation.Order;
import org.myframework.aop.aspect.AspectInfo;
import org.myframework.aop.aspect.DefaultAspect;
import org.myframework.core.BeanContainer;
import org.myframework.util.ValidationUtil;import java.util.ArrayList;
import java.util.List;
import java.util.Set;/*** @author wuyiccc* @date 2020/6/16 8:49* 岂曰无衣，与子同袍~*/
public class AspectWeaver {private BeanContainer beanContainer;public AspectWeaver() {beanContainer = BeanContainer.getInstance();}public void doAop() {// 1. 获取所有的切面类Set<Class<?>> aspectSet = beanContainer.getClassesByAnnotation(Aspect.class);if (ValidationUtil.isEmpty(aspectSet)) {return;}// 2. 拼装AspectInfoListList<AspectInfo> aspectInfoList = packAspectInfoList(aspectSet);// 3. 遍历容器里的类Set<Class<?>> classSet = beanContainer.getClasses();for (Class<?> targetClass : classSet) {// 排除AspectClass自身if (targetClass.isAnnotationPresent(Aspect.class)) {continue;}// 4. 粗筛符和条件的AspectList<AspectInfo> roughMatchedAspectList = collectRoughMatchAspectListForSpecificClass(aspectInfoList, targetClass);// 5. 尝试进行Aspect织入wrapIfNecessary(roughMatchedAspectList, targetClass);}}private void wrapIfNecessary(List<AspectInfo> roughMatchedAspectList, Class<?> targetClass) {if (ValidationUtil.isEmpty(roughMatchedAspectList)) {return;}// 创建动态代理对象AspectListExecutor aspectListExecutor = new AspectListExecutor(targetClass, roughMatchedAspectList);Object proxyBean = ProxyCreator.createProxy(targetClass, aspectListExecutor);beanContainer.addBean(targetClass, proxyBean);}private List<AspectInfo> collectRoughMatchAspectListForSpecificClass(List<AspectInfo> aspectInfoList, Class<?> targetClass) {List<AspectInfo> roughMatchedAspectList = new ArrayList<>();for (AspectInfo aspectInfo : aspectInfoList) {// 粗筛if (aspectInfo.getPointcutLocator().roughMatches(targetClass)) {roughMatchedAspectList.add(aspectInfo);}}return roughMatchedAspectList;}private List<AspectInfo> packAspectInfoList(Set<Class<?>> aspectSet) {List<AspectInfo> aspectInfoList = new ArrayList<>();for (Class<?> aspectClass : aspectSet) {if (verifyAspect(aspectClass)) {Order orderTag = aspectClass.getAnnotation(Order.class);Aspect aspectTag = aspectClass.getAnnotation(Aspect.class);DefaultAspect defaultAspect = (DefaultAspect) beanContainer.getBean(aspectClass);// 初始化表达式定位器PointcutLocator pointcutLocator = new PointcutLocator(aspectTag.pointcut());AspectInfo aspectInfo = new AspectInfo(orderTag.value(), defaultAspect, pointcutLocator);aspectInfoList.add(aspectInfo);} else {throw new RuntimeException("@Aspect and @Order must be added to the Aspect class, and Aspect class must extend from DefaultAspect");}}return aspectInfoList;}// 框架中一定要遵守给Aspect添加的@Aspect和@Order标签的规范，同时，必须继承自DefaultAspect.classprivate boolean verifyAspect(Class<?> aspectClass) {return aspectClass.isAnnotationPresent(Aspect.class)&& aspectClass.isAnnotationPresent(Order.class)&& DefaultAspect.class.isAssignableFrom(aspectClass);}
}

5.2 AspectWeaver类相关方法解析：

github地址：https://github.com/wuyiccc/helloframework