为什么java RMI不能通过引用获取返回值 [英] why java RMI can't get return value by reference

问题描述

在RMI中，我只能通过

In RMI, I can only get return value by

InetSocketAddress address = new InetSocketAddress(hostname, port);
Server server = Stub.create(Server.class, address);
int return = server.getValue();

但是，我无法得到它

public class Return {
    int value;
}
InetSocketAddress address = new InetSocketAddress(hostname, port);
Server server = Stub.create(Server.class, address);
Return return = new Return();
server.getValue(return);

我知道参数会被序列化和反序列化，但这不是我的问题，我的问题是为什么 Java 不能像在 C 中使用 RPC 那样模拟传递引用作为传递输入输出?"，我觉得跟java环境有关.通过输入输出我的意思是在带有 RPC 的 C 中，您可以通过

I know arguments will be serialized and deserialized, but that's not my question, my question is "why can't Java emulate a pass-by-reference as a pass by in-out, as was done in C with RPC?", I think it's related to java environment. By in-out I mean in C with RPC, you can get return value by

int return;
rpc.getValue(&return);

希望现在我的问题很清楚了.

Hope now my question is clear.

推荐答案

返回额外的对象代理会带来实施挑战.就目前情况而言，只有一种方法可以创建远程对象.如果允许方法仅通过返回常规对象来产生更多远程对象，那么所有这些调用都需要被拦截，对象正确编目等.

Returning additional object proxies would pose an implementation challenge. As things stand, there's only one way to create a remote object. if methods are allowed to spawn more remote objects just by returning regular objects, then all those calls need to be intercepted, objects properly catalogued, etc.

换句话说，Java 人 - 不像，e.G.DCOM 人 - 决定不做额外的管道.这将永远是为什么系统 A 与系统 B 不同"问题的答案.

In other words, the Java people - unlike , e. g. DCOM people - decided not to do the extra plumbing. And that will always be the answer to the "why is system A unlike system B" quesions.

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