用ProxyFactory实现编程Spring

Question

我在用编程方式实现Spring。我创建了一个简单的工厂类，它使用给定的Object.class列表生成AOP MethodInterceptors代理：

public class AOPProxyFactoryBean implements FactoryBean<Object> {

    private List<MethodInterceptor> methodInterceptors = new ArrayList<MethodInterceptor>();

    public Object getObject() throws Exception {
        Object o = new Object();
        ProxyFactory proxyFactory = new ProxyFactory(o);
        for (MethodInterceptor methodInterceptor : methodInterceptors) {
            proxyFactory.addAdvice(methodInterceptor);
        }
        return proxyFactory.getProxy();
    }

    public Class<?> getObjectType() {
        return Object.class;
    }

    public boolean isSingleton() {
        return false;
    }

    public void setMethodInterceptors(List<MethodInterceptor> methodInterceptors) {
        this.methodInterceptors = methodInterceptors;
    }

一个简单的拦截器：

public class SimpleMethodInterceptor implements MethodInterceptor {

    public Object invoke(MethodInvocation invocation) throws Throwable {
        System.out.println("SimpleMethodInterceptor: " + invocation.getMethod().getName());
        return invocation.proceed();
    }
}

Spring配置：

<bean id="simpleMethodInterceptor" class="...SimpleMethodInterceptor"/>

<bean id="objectAOPProxyFactoryBean" class="...AOPProxyFactoryBean">
    <property name="methodInterceptors">
        <list>
            <ref bean="simpleMethodInterceptor"/>
        </list>
    </property>
</bean>

在docs 这里中，您可以阅读关于addAdvice(建议建议)的以下内容：请注意，给定的通知将应用于代理上的所有调用，甚至适用于toString()方法！

因此，我期望得到对Object.class方法的所有调用，这些调用被SimpleMethodInterceptor截获。

测试：

@Test
public void aopTest() {
    Object o = (Object) applicationContext.getBean("objectAOPProxyFactoryBean");
    o.toString();
    o.equals(o);
    o.getClass();
}

给出这个输出：

SimpleMethodInterceptor: toString

似乎只有toString()方法被截获。知道为什么吗？

Answer 1

很奇怪。对我来说好像是个虫子。我无法确切地解释原因，但我有一个可能的解决办法。创建一个接口并在那里重新定义equals和hashCode：

public interface MadeUpInterface {
    @Override
    public boolean equals(Object obj);

    @Override
    public int hashCode();
}

从代理工厂返回实现该接口的实例。

public Object getObject() throws Exception {
    Object o = new MadeUpInterface() {};
    ProxyFactory proxyFactory = new ProxyFactory(o);
    for (MethodInterceptor methodInterceptor : methodInterceptors) {
        proxyFactory.addAdvice(methodInterceptor);
    }
    return proxyFactory.getProxy();
}

现在，它将打印等于和hashCode。因此，我认为其行为是，它不拦截对仅在对象上定义的方法的调用。toString被视为特例。