Day22 SSM's AOP dynamic agent

Spring AOP concept

• (1) AOP (Aspect Oriented Programming) is aspect-oriented programming.
  It is a technology 预编译that 动态代理realizes the unified maintenance of program functions through mode and operation .
  Simply put, on the basis of not changing the original code of the method, the function enhancement of the method
  essentially generates a new class called代理类
• (2) AOP adopts a dynamic proxy method for program expansion. ( JDK动态代理and Cglib动态代理two methods)
  
  

Spring dynamic proxy

• (1) JDK dynamic proxy
  "method of the
  Proxy class static method of the Proxy class can create proxy objects
  static Object newProxyInstance(ClassLoader loader, Class<?>[] interfaces, InvocationHandler h)
  " three parameters
  Parameter 1: ClassLoader loaderClass loader, used to load the proxy object
  Parameter 2: Class<?>[] interfacesBytecode object array of the target class. Because The proxy is an interface, and you need to know all the methods in the interface.Parameter
  3: InvocationHandler hExecution handle, the core logic of proxy object processing is in this interface
• (2) Case: CEOs eat,
  CEOs,
  secretary

TestJDKProxy

public class TestJDKProxy {
    
    
    @Test
    public  void  Test02(){
    
    
        //Jdk代理
        //ILaoZong
        final LaoZong laoZong = new LaoZong();
        final MiShu miShu = new MiShu();
        //1 创建一个代理类，创建该类的对象
        ClassLoader classLoader = LaoZong.class.getClassLoader();
        Class[] interfaces= new Class[]{
    
    ILaoZong.class};
        //处理器
        InvocationHandler handler = new InvocationHandler() {
    
    
            @Override
            public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
    
    
                //调 laibeijiu()
                miShu.laiBeiJiu();
                //调 eat()
                //laoZong.eat();
                //method 被增加的方法
                Object returnValue = method.invoke(laoZong,args);
                //调 laiGenYan()
                miShu.laiGenYan();
                return returnValue;
            }

        };
        ILaoZong iLaoZong = (ILaoZong) Proxy.newProxyInstance(classLoader,interfaces,handler);
        iLaoZong.eat();
    }
}

ILaoZong

public interface ILaoZong {
    
    
    void eat();
}

LaoZong

public class LaoZong implements ILaoZong {
    
    
    @Override
    public void eat() {
    
    
        System.out.println("eat san xia guo");
        System.out.println("eat wa wa cai");
    }
}

MiShu

public class MiShu {
    
    
    public void laiBeiJiu(){
    
    
        System.out.println("laiBeiJiu");
    }
    public void laiGenYan(){
    
    
        System.out.println("laiGenYan");
    }
}

Execute test result