Java实例讲解动态代理

<!-- proxy-target-class="false"默认使用JDK动态代理 -->
<aop:aspectj-autoproxy proxy-target-class="true"/>
<aop-config proxy-target-class="true">

/**
 * 目标接口类
 */
public interface UserManager {    
    public void addUser(String id, String password);    
    public void delUser(String id);    
}

/**
 * 接口实现类
 */
public class UserManagerImpl implements UserManager {    
    @Override
    public void addUser(String id, String password) {    
        System.out.println("调用了UserManagerImpl.addUser()方法！");
    }    
    @Override
    public void delUser(String id) {    
        System.out.println("调用了UserManagerImpl.delUser()方法！");
    }    
}

/**
 * JDK动态代理类
 */
public class JDKProxy implements InvocationHandler {    
    // 需要代理的目标对象
    private Object targetObject;    
    public Object newProxy(Object targetObject) {
        // 将目标对象传入进行代理    
        this.targetObject = targetObject;
        // 返回代理对象 
        return Proxy.newProxyInstance(targetObject.getClass().getClassLoader(), targetObject.getClass().getInterfaces(), this);
    }    
    // invoke方法
    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        // 进行逻辑处理的函数
        checkPopedom();
        Object ret = null;
        // 调用invoke方法
        ret = method.invoke(targetObject, args);
        return ret;
    }    
    private void checkPopedom() {
        // 模拟检查权限   
        System.out.println("检查权限：checkPopedom()!");    
    }    
} 

/**
 * CGlib动态代理类
 */
 public class CGLibProxy implements MethodInterceptor {    
    // CGlib需要代理的目标对象
    private Object targetObject;
    public Object createProxyObject(Object obj) {
        this.targetObject = obj;
        Enhancer enhancer = new Enhancer();
        enhancer.setSuperclass(obj.getClass());
        enhancer.setCallback(this);
        Object proxyObj = enhancer.create();
        return proxyObj;
    }
    @Override
    public Object intercept(Object proxy, Method method, Object[] args, MethodProxy methodProxy) throws Throwable {
        Object obj = null;
        // 过滤方法
        if ("addUser".equals(method.getName())) {
            // 检查权限
            checkPopedom();
        }
        obj = method.invoke(targetObject, args);
        return obj;
    }    
    private void checkPopedom() {
        System.out.println("检查权限：checkPopedom()!");
    }
}

/**
 * 测试类
 */
public class ProxyTest {
    public static void main(String[] args) {
        UserManager userManager = (UserManager)new CGLibProxy().createProxyObject(new UserManagerImpl());
        System.out.println("CGLibProxy：");
        userManager.addUser("tom", "root");
        System.out.println("JDKProxy：");
        JDKProxy jdkProxy = new JDKProxy();
        UserManager userManagerJDK = (UserManager)jdkProxy.newProxy(new UserManagerImpl());
        userManagerJDK.addUser("tom", "root");
    }
}