动态代理

主营业务接口：

public interface IUserManger {
    public void AddUser(String UserName, String Password);
    public void ModifyUser(int id, String UserName, String Password);

}

接口实现类：

public class UserManagerImpl implements IUserManager{


    public void addUser(String username, String password) {
        System.out.println("=========UserManagerImpl.addUser()===========");
    }

    public void modifyUser(int id, String username, String password) {
        System.out.println("=========UserManagerImpl.modifyUser()===========");
    }
}

继承invocationHandler的类：

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

//帮助我们动态的生成代理对象JDK1.5

public class SecurityHandler implements InvocationHandler {

    private Object targetObject;//目标对象

    //生成代理对象
    public Object proxyInstance(Object paramObject){
        this.targetObject = paramObject;
        return Proxy.newProxyInstance(
                this.targetObject.getClass().getClassLoader(),
                this.targetObject.getClass().getInterfaces(),
                this);//得到目标加载器实现invocationHandler的类，也就是本类
    }

    //传入代理对象，目标对象的方法，方法参数，代理方法与目标方法都实现了IUserManager
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        Object resultObj = null;
        checkSecurity();
        try{
            resultObj = method.invoke(this.targetObject,args);//递归调用
        }catch (Exception ex){
            ex.printStackTrace();
        }
        return resultObj;
    }

    public void checkSecurity(){
        System.out.println("=======checkSecurity()==========");
    }
}

测试类：

public class Client {

    public static void main(String[] args) {
        SecurityHandler securityHandler = new SecurityHandler();
        IUserManager iUserManager = (IUserManager) securityHandler.proxyInstance(new UserManagerImpl());
        iUserManager.addUser("abc","123");

    }
}