java - 从 C# 客户端向 Java 服务器发送数据 - 数据不一致。

Question

我不确定这里的问题是什么，但似乎我发送到 Java 的所有数据都已损坏。它在 Java 客户端上工作得很好，我已经验证了两种语言之间每个原语的字节大小。

我将从客户端的 C# 方面开始，因为我已将其简化:

这是 PacketBuilder 类。

/// <summary>
    /// Used to build a instance of the <see cref="UnityNetworking.Packet"/> class.
    /// </summary>
    public class PacketBuilder {

        /// <summary>
        /// The opcode of the packet being built.
        /// </summary>
        private int Opcode;

        /// <summary>
        /// The stream to write data to the packet's buffer.
        /// </summary>
        private MemoryStream stream;

        /// <summary>
        /// The binary writer to convert data into binary format.
        /// </summary>
        private BinaryWriter writer;

        /// <summary>
        /// The String encoder.
        /// </summary>
        private Encoding encoder;

        /// <summary>
        /// Create a new PacketBuilder instance with the specified opcode and a default capacity.
        /// </summary>
        /// <param name="opcode">The opcode.</param>
        public static PacketBuilder Create(int opcode) {
            return new PacketBuilder (opcode, 512);
        }

        /// <summary>
        /// Create a new PacketBuilder instance with the specified opcode and capacity.
        /// </summary>
        /// <param name="opcode">The opcode.</param>
        /// <param name="capacity">The buffer capacity.</param>
        public static PacketBuilder Create(int opcode, int capacity) {
            return new PacketBuilder (opcode, capacity);
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="UnityNetworking.PacketBuilder"/> class.
        /// </summary>
        /// <remarks>Private scope to prevent outside library instantiation.</remarks>
        private PacketBuilder (int opcode, int capactiy) {
            Opcode = opcode;
            stream = new MemoryStream (capactiy);
            writer = new BinaryWriter (stream);
            encoder = new UTF8Encoding (true, true);
        }

        /// <summary>
        /// Adds the specified data to the builders buffer.
        /// </summary>
        /// <param name="data">The data.</param>
        public PacketBuilder Add(object data) {
            if (data is Int16) {
                writer.Write ((short)data);
            } else if (data is Int32) {
                writer.Write ((int)data);
            } else if (data is Int64) {
                writer.Write ((long)data);
            } else if (data is Single) {
                writer.Write ((float)data);
            } else if (data is Double) {
                writer.Write ((double)data);
            } else if (data is Byte) {
                writer.Write ((byte)data);
            } else if (data is Boolean) {
                writer.Write ((bool)data);
            } else if (data is String) {
                string str = (string)data;
                byte[] bytes = encoder.GetBytes (str);
                writer.Write ((short)bytes.Length);
                writer.Write (bytes, 0, bytes.Length);
            } else {
                throw new Exception ("Unsupported Object Type: " + data);
            }
            Debug.Log ("Data Type: " + data.GetType() + " || Value: " + data);
            return this;
        }

        public Packet ToPacket() {
            return new Packet(Opcode, stream.ToArray());
        }
    }

如您所见，此类使用 MemoryStream 和 BinaryWriter 作为我要发送的示例 我将使用 long 值或在 C# 中通常称为 Int64。

    PacketBuilder builder = PacketBuilder.Create(1);
    builder.Add((byte)1);
    builder.Add(1337L);
    client.Write(builder.ToPacket());

这是通过 Client 类中的 Write(Packet) 方法发送的，可在此处找到:

public NetworkClient Write(Packet packet) {
    networkStream.Write (packet.Buffer, 0, packet.Size);
    return this;
}

非常基础:现在在 Java 端，所有内容都被放入 ByteBuffer 中，使用 getX 方法获取数据。

获取这些数据的方式如下:

public boolean handle(long userId, Session session, Packet packet) {
    ByteBuffer buffer = packet.getBuffer();
    byte opcode = buffer.get();
    userId = buffer.getLong();
    System.out.println("Opcode: " + opcode + " || User ID: " + userId);
}

这会输出以下行:

Opcode: 1 || User ID: 4108690235045445632

我完全不明白这是怎么回事，尤其不明白 1337 怎么会变成只有上帝知道这个数字是多少。从客户端调试时，会出现以下信息:

Data Type: System.Byte || Value: 1
Data Type: System.Int64 || Value: 1337

所以，如果有人能告诉我发生了什么事，那就太好了。

Answer 1

您的 64 位整数有不同的字节顺序。

您得到的值是 1337L，即 0x0539。如果你反转这个字节值，你会得到 0x3905000000000000。将其转换为十进制，您将得到 4108690235045445632。

通常，当通过网络发送原始数据(如数据包)时，您将使用 lton(value) 之类的东西来发送，并使用 ntol(value) 来处理您收到的值。我不确定 C# 和 Java 的等价物是什么，但这些是“long to network”和“network to long”函数。同样，您可以对 short 和其他类型(8 位值除外)执行此操作。