jdk静态代理
interface Dao {
void save();
}
class DaoImpl implements Dao {
@Override
public void save() {
System.out.println("save...");
}
}
class DaoProxy implements Dao{
private Dao target;
public DaoProxy(Dao target) {
this.target = target;
}
@Override
public void save() {
System.out.println("before...");
target.save();
System.out.println("after...");
}
}
public class StaticProxyTest {
public static void main(String[] args) {
DaoImpl target = new DaoImpl();
Dao userDao = new DaoProxy(target);
userDao.save();
}
}
jdk动态代理(代理接口)
interface Dao {
void save();
}
class DaoImpl implements Dao {
@Override
public void save() {
System.out.println("save...");
}
}
public class DynamicProxyTest {
public static void main(String[] args) {
Object target = new DaoImpl();
/**
* loader：业务对象的类加载器
* interfaces：业务对象实现的所有的接口，可直接指定业务类实现的接口 Class[]
* h：InvocationHandler 对象，最终由它调用业务对象的方法
* public static Object newProxyInstance(ClassLoader loader, Class<?>[] interfaces, InvocationHandler h)
*/
Dao dao = (Dao) Proxy.newProxyInstance(DaoImpl.class.getClassLoader(), new Class<?>[]{Dao.class}, new InvocationHandler() {
/**
* @param proxy 代理对象
* @param method 代理的方法对象
* @param args 方法调用时参数
*/
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
Object result = null;
if (method.getName().equals("save")) {
System.out.println("before...");
result = method.invoke(target, args);
System.out.println("after...");
}
return result;
}
});
dao.save();
}
}
cglib代理(代理类)
public class Dao {
public void select() {
System.out.println("select()");
}
}
public class DaoProxy implements MethodInterceptor {
/**
* @param object 要进行增强的对象
* @param method 拦截的方法
* @param objects 参数列表，基本数据类型需要传入其包装类型
* @param proxy 对方法的代理，invokeSuper 方法表示对被代理对象方法的调用
*/
@Override
public Object intercept(Object object, Method method, Object[] objects, MethodProxy proxy) throws Throwable {
System.out.println("Before Method Invoke");
proxy.invokeSuper(object, objects);
System.out.println("After Method Invoke");
return object;
}
}
public static void main(String[] args) {
DaoProxy daoProxy = new DaoProxy();
Enhancer enhancer = new Enhancer();
enhancer.setSuperclass(Dao.class);
enhancer.setCallback(daoProxy);
Dao dao = (Dao) enhancer.create();
dao.select();
}