SpringAOP-Spring中的AOP

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SpringAOP

• 如果目标对象实现了接口，则默认采用JDK动态代理
• 如果目标对象没有实现接口，则采用Cglib进行动态代理
• 如果目标对象实现了接口，且强制cglib代理，则使用cglib代理

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链式调用AOP

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例子

public abstract class Handler {

    private Handler sucessor;

    public Handler getSucessor() {
        return sucessor;
    }

    public void setSucessor(Handler sucessor) {
        this.sucessor = sucessor;
    }

    public void execute(){
        handleProcess();
        if(sucessor != null){
            sucessor.execute();
        }
    }

    protected abstract void handleProcess();
}

客户端调用

public class Client {
    static class HandlerA extends Handler{
        @Override
        protected void handleProcess() {
            System.out.println("handle by a");
        }
    }
    static class HandlerB extends Handler{
        @Override
        protected void handleProcess() {
            System.out.println("handle by b");
        }
    }
    static class HandlerC extends Handler{
        @Override
        protected void handleProcess() {
            System.out.println("handle by c");
        }
    }

    public static void main(String[] args){
        Handler handlerA = new HandlerA();
        Handler handlerB = new HandlerB();
        Handler handlerC = new HandlerC();

        handlerA.setSucessor(handlerB);
        handlerB.setSucessor(handlerC);

        handlerA.execute();
    }
}

改造

public abstract class ChainHandler {

    public void execute(Chain chain){
        handleProcess();
        chain.proceed();
    }

    protected abstract void handleProcess();
}

public class Chain {

    private List<ChainHandler> handlers;

    private int index = 0;

    public Chain(List<ChainHandler> handlers) {
        this.handlers = handlers;
    }

    public void proceed(){
        if(index >= handlers.size()){
            return ;
        }
        handlers.get(index++).execute(this);
    }
}

客户端

public class ChainClient {
    static class ChainHandlerA extends ChainHandler{
        @Override
        protected void handleProcess() {
            System.out.println("handle by chain a");
        }
    }
    static class ChainHandlerB extends ChainHandler{
        @Override
        protected void handleProcess() {
            System.out.println("handle by chain b");
        }
    }
    static class ChainHandlerC extends ChainHandler{
        @Override
        protected void handleProcess() {
            System.out.println("handle by chain c");
        }
    }

    public static void main(String[] args){
        List<ChainHandler> handlers = Arrays.asList(
                new ChainHandlerA(),
                new ChainHandlerB(),
                new ChainHandlerC()
        );
        Chain chain = new Chain(handlers);
        chain.proceed();
    }
}
##SpringAOP中AOP责任链
![图片.png](https://img.haomeiwen.com/i6720201/b74dfe8179d6e96f.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)