【小家Spring】Spring AOP核心类Pointcut解析，对PointcutExpression切点表达式解析原理分析（以AspectJExpressionPointcut为例）（下）

public class Main {
    public static void main(String[] args) {
        ProxyFactory factory = new ProxyFactory(new Person());
        // 声明一个通知（此处使用环绕通知 MethodInterceptor ）
        Advice advice = (MethodInterceptor) invocation -> {
            System.out.println("============>放行前拦截...");
            Object obj = invocation.proceed();
            System.out.println("============>放行后拦截...");
            return obj;
        };
        // 先创建一个流程切入点
        ControlFlowPointcut controlFlowPointcut = new ControlFlowPointcut(Main.class, "funabc");
        // 再创建一个方法名切入点
        NameMatchMethodPointcut nameMatchMethodPointcut = new NameMatchMethodPointcut();
        nameMatchMethodPointcut.addMethodName("say");
        // 创建一个复合切点 把上面两者并且进来
        ComposablePointcut cut = new ComposablePointcut();
        cut.intersection((Pointcut) controlFlowPointcut).intersection((Pointcut)nameMatchMethodPointcut);
        // 切点+通知（注意：此处放的是复合切面）
        Advisor advisor = new DefaultPointcutAdvisor(cut, advice);
        factory.addAdvisor(advisor);
        Person p = (Person) factory.getProxy();
        // 执行方法
        p.run();
        p.run(10);
        p.say();
        p.sayHi("Jack");
        p.say("Tom", 666);
        funabc(p);
    }
    private static void funabc(Person person) {
        person.run();
        person.say();
    }
}
输出：
我在run...
我在run...<10>
我在say...
Hi,Jack,你好
Tom----666
我在run...
============>放行前拦截...
我在say...
============>放行后拦截...

public class ComposablePointcut implements Pointcut, Serializable {
  // 它持有ClassFilter 和 MethodMatcher ，最终通过它去组合匹配
  private ClassFilter classFilter;
  private MethodMatcher methodMatcher;
  // 构造函数一个共5个
  // 匹配所有类所有方法的复合切点
  public ComposablePointcut() {
    this.classFilter = ClassFilter.TRUE;
    this.methodMatcher = MethodMatcher.TRUE;
  }
  // 匹配特定切点的复合切点（相当于把这个节点包装了一下而已）
  public ComposablePointcut(Pointcut pointcut) {
    Assert.notNull(pointcut, "Pointcut must not be null");
    this.classFilter = pointcut.getClassFilter();
    this.methodMatcher = pointcut.getMethodMatcher();
  }
  // 匹配特定类**所有方法**的复合切点
  public ComposablePointcut(ClassFilter classFilter) {
    Assert.notNull(classFilter, "ClassFilter must not be null");
    this.classFilter = classFilter;
    this.methodMatcher = MethodMatcher.TRUE;
  }
  // 匹配**所有类**特定方法的复合切点
  public ComposablePointcut(MethodMatcher methodMatcher) {
    Assert.notNull(methodMatcher, "MethodMatcher must not be null");
    this.classFilter = ClassFilter.TRUE;
    this.methodMatcher = methodMatcher;
  }
  // 匹配特定类特定方法的复合切点（这个是最为强大的）
  public ComposablePointcut(ClassFilter classFilter, MethodMatcher methodMatcher) {
    Assert.notNull(classFilter, "ClassFilter must not be null");
    Assert.notNull(methodMatcher, "MethodMatcher must not be null");
    this.classFilter = classFilter;
    this.methodMatcher = methodMatcher;
  }
  // 匹配特定类特定方法的复合切点（这个是最为强大的）
  public ComposablePointcut union(ClassFilter other) {
    this.classFilter = ClassFilters.union(this.classFilter, other);
    return this;
  }
  // ==========3个并集(union) / 3个交集(intersection) 运算的方法========
  public ComposablePointcut intersection(ClassFilter other) {
    this.classFilter = ClassFilters.intersection(this.classFilter, other);
    return this;
  }
  public ComposablePointcut union(MethodMatcher other) {
    this.methodMatcher = MethodMatchers.union(this.methodMatcher, other);
    return this;
  }
  public ComposablePointcut intersection(MethodMatcher other) {
    this.methodMatcher = MethodMatchers.intersection(this.methodMatcher, other);
    return this;
  }
  public ComposablePointcut union(Pointcut other) {
    this.methodMatcher = MethodMatchers.union(
        this.methodMatcher, this.classFilter, other.getMethodMatcher(), other.getClassFilter());
    this.classFilter = ClassFilters.union(this.classFilter, other.getClassFilter());
    return this;
  }
  public ComposablePointcut intersection(Pointcut other) {
    this.classFilter = ClassFilters.intersection(this.classFilter, other.getClassFilter());
    this.methodMatcher = MethodMatchers.intersection(this.methodMatcher, other.getMethodMatcher());
    return this;
  }
  ...
}

//仅指定类级别的注解， 标注了 ClassLevelAnnotation 注解的类中的**所有方法**执行的时候，将全部匹配。  
AnnotationMatchingPointcut pointcut = new AnnotationMatchingPointcut(ClassLevelAnnotation.class);  
// === 还可以使用静态方法创建 pointcut 实例  
AnnotationMatchingPointcut pointcut = AnnotationMatchingPointcut.forClassAnnotation(ClassLevelAnnotation.class);  
//仅指定方法级别的注解，标注了 MethodLeavelAnnotaion 注解的**方法（忽略类匹配）都将匹配**  
AnnotationMatchingPointcut pointcut = AnnotationMatchingPointcut.forMethodAnnotation(MethodLevelAnnotation.class);  
==========这个是同时想限定：===============
//同时限定类级别和方法级别的注解，只有标注了 ClassLevelAnnotation 的类中 ***同时***标注了 MethodLevelAnnotation 的方法才会匹配  
AnnotationMatchingPointcut pointcut = new AnnotationMatchingPointcut(ClassLevelAnnotation.class, MethodLevelAnnotation.class);