一张图看懂jdk动态代理机制

public class JdkProxy implements InvocationHandler{
    private Trancation2 trancation;
    private Ihello target;

    public JdkProxy(Trancation2 trancation, Ihello target) {
        this.trancation = trancation;
        this.target = target;
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        // 开启事务
        trancation.beginTrancation();
        // 方法调用，注！！！此处传入的Object为代理，而不是目标类，目标类需要另外注入
        Object obj = method.invoke(target, args);
        // 开启事务
        trancation.commit();
        return obj;
    }
}
// jdk的代理需要实现接口
interface  Ihello{
    void sayHello();
}
// 人员DAO
class IHeloImpl implements Ihello{
    @Override
    public void sayHello() {
        System.out.println("保存人员");
    }
}
// 事务
class Trancation2 {
    public void beginTrancation() {
        System.out.println("开启事务");
    }

    public void commit() {
        System.out.println("提交事务");
    }
}
// 客户端
class Client2 {
    public static void main(String[] args) {
        Trancation2 t2 = new Trancation2();
        Ihello helo = new IHeloImpl();
        JdkProxy jdkProxy = new JdkProxy(t2,helo);
        Ihello helloProxy = (Ihello) Proxy.newProxyInstance(helo.getClass().getClassLoader(),helo.getClass().getInterfaces(),jdkProxy);
        helloProxy.sayHello();
    }
}