Overview
RMI 协议使用了两种其他协议用于网络通信：Java 序列化和 HTTP。序列化协议用于执行 marshal call 和返回数据，而 HTTP 用于“提交”远程方法调用并在需要的时候获取返回数 据。
link: https://docs.oracle.com/javase/9/docs/specs/rmi/protocol.html
Format of an Output Stream
An output stream in RMI consists of transport Header information followed by a sequence of Messages. Alternatively, an output stream can contain an invocation embedded in the HTTP protocol.
- Out: Header Messages HttpMessage
- Header: 0x4a 0x52 0x4d 0x49 Version Protocol
- Version: 0x00 0x01
- Protocol: StreamProtocol SingleOpProtocol MultiplexProtocol
- StreamProtocol: 0x4b
- SingleOpProtocol: 0x4c
- MultiplexProtocol: 0x4d
- Messages: Message Messages Message
Format of an Input Stream
There are currently three types of input messages: ReturnData, HttpReturn and PingAck. ReturnData is the result of a “normal” RMI call. An HttpReturn is a return result from an invocation embedded in the HTTP protocol. A PingAck is the acknowledgment for a Ping message.
- In: ProtocolAck Returns ProtocolNotSupported HttpReturn
- ProtocolAck: 0x4e
- ProtocolNotSupported: 0x4f
- Returns: Return Returns Return
- Return: ReturnData PingAck
- ReturnData: 0x51 ReturnValue
- PingAck: 0x53