java – 动态代理和检查异常

您可以使用动态代理.只要检查的异常是接口的一部分,您可以从调用处理程序中抛出检查的异常.否则,这是非法的,并将创建一个UndeclaredThrowableException来包装抛出的检查的异常.

interface A{
    void x() throws IOException;
}

A proxy = (A) newProxyInstance(classLoader,new Class<?>[]{A.class},new InvocationHandler() {      
        @Override
        public Object invoke(Object arg0,Method arg1,Object[] arg2) 
            throws Throwable {
            throw new IOException();
        }
   }
);
proxy.x();

输出：

Exception in thread "main" java.io.IOException
at X$1.invoke(X.java:19)
at $Proxy0.x(UnkNown Source)
at X.main(X.java:22)

对于接口A,未经声明的检查异常：

interface A{
    void x();
}

Exception in thread "main" java.lang.reflect.UndeclaredThrowableException
  at $Proxy0.x(UnkNown Source)
  at X.main(X.java:22)
Caused by: java.io.IOException
  at X$1.invoke(X.java:19)
  ... 2 more