JAVA AOP 动态代理的例子

最新推荐文章于 2023-12-22 17:30:31 发布

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最新推荐文章于 2023-12-22 17:30:31 发布

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分类专栏： java 文章标签： AOP 动态代理

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本文介绍了一个使用Java反射和动态代理实现的简单面向切面编程(AOP)案例。通过自定义`myAOP`类作为调用处理器，并对`student`类的方法调用前后增加额外的操作，展示了AOP的基本原理。

package myaop;
import java.util.*;
import java.lang.reflect.*;

interface person {
String getName();
int getID();
}

class student implements person{
private String name;
private int id;
student(){
System.out.println("student: student() called ");
name="nonmae";
id=0;
}
student(int mid, String name){
this.name=name;
this.id=mid;
}
public String getName(){
System.out.println("student: getName() called. Name= "+name);
return name;
}
public int getID() {
System.out.println("student: getID() called: id= "+id);
return id;
}
}
class actions {
public void BeforeActions(){
System.out.println("actions: BeforeActions() called ");
}
public void AfterActions(){
System.out.println("actions: AfterActions() called ");
}
}

class myAOP implements InvocationHandler{
public Object proxyee;
public void setTarget(Object target){
proxyee=target;
}

public Object invoke(Object myproxy, Method method, Object[] args){
System.out.println("myAOP:invoke() enters");
actions maction = new actions();
maction.BeforeActions();

Object result=null;
try {
result=method.invoke(proxyee,args);
}

catch (IllegalAccessException | IllegalArgumentException
| InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

maction.AfterActions();
return result;
}
}

public class AOPTrial {
public static void main(String[] args) {
// TODO Auto-generated method stub
person sta = new student(1,"jac2k");
myAOP handler = new myAOP();
handler.setTarget(sta);
Object mystu=Proxy.newProxyInstance(sta.getClass().getClassLoader(),
sta.getClass().getInterfaces(),handler);
/*
* student: getID() called: id= 1
* student: getName() called. Name= jac2k
*/
((person)sta).getID();
((person)sta).getName();

/*
myAOP:invoke() enters
actions: BeforeActions() called
student: getID() called: id= 1
actions: AfterActions() called
myAOP:invoke() enters
actions: BeforeActions() called
student: getName() called. Name= jac2k
actions: AfterActions() called
*/
//here can't covert to student
((person)mystu).getID();
((person)mystu).getName();

}

}

输出结果

student: getID() called: id= 1
student: getName() called. Name= jac2k
myAOP:invoke() enters
actions: BeforeActions() called
student: getID() called: id= 1
actions: AfterActions() called
myAOP:invoke() enters
actions: BeforeActions() called
student: getName() called. Name= jac2k
actions: AfterActions() called