Spring繁华的AOP王国---第二讲

Posted 2022-03-25 大忽悠爱忽悠

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Spring繁华的AOP王国---第二讲

Spring AOP的织入
TargetSource
- 可用的targetSource实现类

Spring AOP的织入

如何与ProxyFactory打交道

public interface ITask 
    void excute();

public class MockTask implements ITask
    @Override
    public void excute() 
        System.out.println("task excuted!");

public class PerformanceMethodInterceptor implements MethodInterceptor 
    @Nullable
    @Override
    public Object invoke(@Nonnull MethodInvocation methodInvocation) throws Throwable 
        long start = System.currentTimeMillis();
        System.out.println("方法执行前...");
        Thread.sleep(1000);
        Object proceed = methodInvocation.proceed();
        Thread.sleep(1000);
        System.out.println("方法执行后");
        long end = System.currentTimeMillis();
        System.out.println("方法执行总耗时: "+String.valueOf(end-start));
        return proceed;

1.基于接口的代理

        MockTask task=new MockTask();
        ProxyFactory weaver=new ProxyFactory(task);
        weaver.setInterfaces(ITask.class);
        NameMatchMethodPointcutAdvisor advisor=new NameMatchMethodPointcutAdvisor();
        advisor.setMappedName("excute");
        advisor.setAdvice(new PerformanceMethodInterceptor());
        weaver.addAdvisor(advisor);
        ITask proxyObject= (ITask) weaver.getProxy();
        proxyObject.excute();

        MockTask task=new MockTask();
        ProxyFactory weaver=new ProxyFactory(task);
        NameMatchMethodPointcutAdvisor advisor=new NameMatchMethodPointcutAdvisor();
        advisor.setMappedName("excute");
        advisor.setAdvice(new PerformanceMethodInterceptor());
        weaver.addAdvisor(advisor);
        ITask proxyObject= (ITask) weaver.getProxy();
        proxyObject.excute();

2.基于类的代理

public class MockTask 
    public void excute() 
        System.out.println("task excuted!");

        MockTask task=new MockTask();
        ProxyFactory weaver=new ProxyFactory(task);
        NameMatchMethodPointcutAdvisor advisor=new NameMatchMethodPointcutAdvisor();
        advisor.setMappedName("excute");
        advisor.setAdvice(new PerformanceMethodInterceptor());
        weaver.addAdvisor(advisor);
        MockTask proxy = (MockTask)weaver.getProxy();
        proxy.excute();
        System.out.println(proxy.getClass());

3.Introduction的织入

看清ProxyFactory的本质

public interface AopProxy 
    Object getProxy();

    Object getProxy(@Nullable ClassLoader var1);

public interface AopProxyFactory 
    AopProxy createAopProxy(AdvisedSupport var1) throws AopConfigException;

public class DefaultAopProxyFactory implements AopProxyFactory, Serializable 
    public DefaultAopProxyFactory() 
    

    public AopProxy createAopProxy(AdvisedSupport config) throws AopConfigException 
        if (NativeDetector.inNativeImage() || !config.isOptimize() && !config.isProxyTargetClass() && !this.hasNoUserSuppliedProxyInterfaces(config)) 
            return new JdkDynamicAopProxy(config);
         else 
            Class<?> targetClass = config.getTargetClass();
            if (targetClass == null) 
                throw new AopConfigException("TargetSource cannot determine target class: Either an interface or a target is required for proxy creation.");
             else 
                return (AopProxy)(!targetClass.isInterface() && !Proxy.isProxyClass(targetClass) ? new ObjenesisCglibAopProxy(config) : new JdkDynamicAopProxy(config));
            
        
    

    private boolean hasNoUserSuppliedProxyInterfaces(AdvisedSupport config) 
        Class<?>[] ifcs = config.getProxiedInterfaces();
        return ifcs.length == 0 || ifcs.length == 1 && SpringProxy.class.isAssignableFrom(ifcs[0]);

ProxyConfig

public class ProxyConfig implements Serializable 
    private static final long serialVersionUID = -8409359707199703185L;
    private boolean proxyTargetClass = false;
    private boolean optimize = false;
    boolean opaque = false;
    boolean exposeProxy = false;
    private boolean frozen = false;
    ....

Advised

public interface Advised extends TargetClassAware 
    boolean isFrozen();

    boolean isProxyTargetClass();

    Class<?>[] getProxiedInterfaces();

    boolean isInterfaceProxied(Class<?> var1);

    void setTargetSource(TargetSource var1);

    TargetSource getTargetSource();

    void setExposeProxy(boolean var1);

    boolean isExposeProxy();

    void setPreFiltered(boolean var1);

    boolean isPreFiltered();

    Advisor[] getAdvisors();

    default int getAdvisorCount() 
        return this.getAdvisors().length;
    

    void addAdvisor(Advisor var1) throws AopConfigException;

    void addAdvisor(int var1, Advisor var2) throws AopConfigException;

    boolean removeAdvisor(Advisor var1);

    void removeAdvisor(int var1) throws AopConfigException;

    int indexOf(Advisor var1);

    boolean replaceAdvisor(Advisor var1, Advisor var2) throws AopConfigException;

    void addAdvice(Advice var1) throws AopConfigException;

    void addAdvice(int var1, Advice var2) throws AopConfigException;

    boolean removeAdvice(Advice var1);

    int indexOf(Advice var1);

    String toProxyConfigString();

AdvisedSupport

ProxyFactory,AopProxy,AdvisedSupport与ProxyFactory的关系

小结

上面的图只是画了一个大概的联系，大家再结合上面的文件好好理解一下

ProxyCreatorSupport内部拥有一个AopProxyFactory的对象实例，但是获取AopProxy的时候，是通过AopProxyFactory 的createAopProxy方法中传入自身实例ProxyCreatorSupport，来得到一个指定的AopProxy的，通过AopProxy 我们就可以获取到被代理后的对象

之说以传入自身，是因为ProxyCreatorSupport实现了AdvisedSupport，AdvisedSupport又实现了Advised接口，可以因此来获取到被代理对象实例和横切逻辑

public class ProxyCreatorSupport extends AdvisedSupport 
    private AopProxyFactory aopProxyFactory;
    private final List<AdvisedSupportListener> listeners = new ArrayList();
    private boolean active = false;

    public ProxyCreatorSupport() 
        this.aopProxyFactory = new DefaultAopProxyFactory();
    
    
    public ProxyCreatorSupport(AopProxyFactory aopProxyFactory) 
        Assert.notNull(aopProxyFactory, "AopProxyFactory must not be null");
        this.aopProxyFactory = aopProxyFactory;
    
    ....
    protected final synchronized AopProxy createAopProxy() 
        if (!this.active) 
            this.activate();
        

        return this.getAopProxyFactory().createAopProxy(this);

容器中的织入器—ProxyFactoryBean

ProxyFactoryBean的本质

    @Nullable
    public Object getObject() throws BeansException 
        this.initializeAdvisorChain();
        if (this.isSingleton()) 
            return this.getSingletonInstance();
         else 
            if (this.targetName == null) 
                this.logger.info("Using non-singleton proxies with singleton targets is often undesirable. Enable prototype proxies by setting the 'targetName' property.");
            

            return this.newPrototypeInstance();