public class Person {
 private String name;
 public boolean saySomething(String something){
  System.out.println("Pereson類中說(shuō)了一句："+something);
return true;//默認(rèn)返回true
 }
 public String getName() {
  return name;
 }
 public void setName(String name) {
  this.name = name;
 }
}

/**
 * 前置通知類
 */
public class BeforeAdvice implements MethodBeforeAdvice {


 @Override
 public void before(Method method, Object[] objects, @Nullable Object o) throws Throwable {
   //第一個(gè)參數(shù)是目標(biāo)方法對(duì)象，第二個(gè)是參數(shù),第三個(gè)是做為調(diào)用目標(biāo)的object(這是personr實(shí)例)
  //打印方法名
  System.out.println("要執(zhí)行的方法是："+method.getName());
  //修改參數(shù)為lyn4ever
  objects[0]="lyn4ever";//我們修改成為了lyn4ever,所以打印出來(lái)的就是lyn4ever，而不是zhangsan
 }


 public static void main(String[] args) {
  Person person = new Person();

  ProxyFactory pf =new ProxyFactory();
  pf.addAdvice(new BeforeAdvice());
  pf.setTarget(person);

  Person proxy = (Person) pf.getProxy();

  //我這里傳的參數(shù)是zhangsan,理論上它應(yīng)該打印出來(lái)zhangsan
  proxy.saySomething("zhangsan");
 }
}

/**
 * 后置返回通知
 */
public class AfterReturnAdvice implements AfterReturningAdvice {

 @Override
 public void afterReturning(@Nullable Object o, Method method, Object[] objects, @Nullable Object o1) throws Throwable {
  /*
  參數(shù)和前置通知是一樣的
  這個(gè)是在返回之后調(diào)用，因此，person中的saySomething會(huì)先打印，我們?cè)谶@里修改的參數(shù)不起作任何作用
   */

  System.out.println("調(diào)用的方法是:"+method.getName()+"這句是在saySomething之后");//這句是在saySomething之后
  objects[0]="lyn4ever";//這句可以修參數(shù)，但是之前的方法已經(jīng)執(zhí)行過(guò)了，所以不起任何作用

  System.out.println("我們修改了參數(shù)為:"+objects[0]+"但是沒(méi)有任何用");//這時(shí)候這個(gè)參數(shù)并不會(huì)傳到person.saysomething(),因?yàn)橐呀?jīng)調(diào)用過(guò)了

 }


 public static void main(String[] args) {
  Person person = new Person();

  ProxyFactory pf = new ProxyFactory();
  pf.addAdvice(new AfterReturnAdvice());//注意修改這個(gè)為當(dāng)前類中的通知類
  pf.setTarget(person);

  Person proxy = (Person) pf.getProxy();
  proxy.saySomething("zhangsan");
 }
}

public class MyMethodInterceptor implements MethodInterceptor {
 @Override
 public Object invoke(MethodInvocation invocation) throws Throwable {
  return null;
 }
}

/**
 * 環(huán)繞通知
 */
public class MyMethodInterceptor implements MethodInterceptor {
 @Override
 public Object invoke(MethodInvocation invocation) throws Throwable {
  
  //在這個(gè)invoation中有一切我們想要的方法相關(guān)
  System.out.println("類名是:"+invocation.getThis().getClass().getName());
  System.out.println("目標(biāo)方法是:"+invocation.getMethod().getName());

  Object[] arguments = invocation.getArguments();//這個(gè)就是參數(shù)
  System.out.println("第一個(gè)參數(shù) 是:"+arguments[0]);

  //我們修改第一個(gè)參數(shù)為lyn4ever
  arguments[0]="lyn4ever";


  invocation.proceed();//執(zhí)行目標(biāo)方法


  System.out.println("這個(gè)是在之后執(zhí)行的");

  return false;//修改返回值
 }


 public static void main(String[] args) {
  Person person = new Person();

  ProxyFactory pf = new ProxyFactory();
  pf.addAdvice(new MyMethodInterceptor());//注意修改這個(gè)為當(dāng)前類中的通知類
  pf.setTarget(person);

  Person proxy = (Person) pf.getProxy();
  boolean flag = proxy.saySomething("zhangsan");
  System.out.println(flag);//方法本來(lái)是要返回true的
 }
}