套接字发送和接收字节数组

In server, I have send a byte array to client through Java socket

在服务器中，我通过Java套接字向客户端发送了一个字节数组

byte[] message = ... ;

DataOutputStream dout = new DataOutputStream(client.getOutputStream());
dout.write(message);

How can I receive this byte array from client?

如何从客户端接收此字节数组？

4 个解决方案

#1

Try this, it's working for me.

Sender:

试试这个，它对我有用。发件人：

byte[] message = ...
Socket socket = ...
DataOutputStream dOut = new DataOutputStream(socket.getOutputStream());

dOut.writeInt(message.length); // write length of the message
dOut.write(message);           // write the message

Receiver:

接收器：

Socket socket = ...
DataInputStream dIn = new DataInputStream(socket.getInputStream());

int length = dIn.readInt();                    // read length of incoming message
if(length>0) {
    byte[] message = new byte[length];
    dIn.readFully(message, 0, message.length); // read the message
}

#2

First, do not use DataOutputStream unless it’s really necessary. Second:

首先，除非确实需要，否则不要使用DataOutputStream。第二：

Socket socket = new Socket("host", port);
OutputStream socketOutputStream = socket.getOutputStream();
socketOutputStream.write(message);

Of course this lacks any error checking but this should get you going. The JDK API Javadoc is your friend and can help you a lot.

当然这没有任何错误检查，但这应该让你去。 JDK API Javadoc是您的朋友，可以为您提供很多帮助。

#3

There is a JDK socket tutorial here, which covers both the server and client end. That looks exactly like what you want.

这里有一个JDK套接字教程，它涵盖了服务器端和客户端。这看起来完全像你想要的。

(from that tutorial) This sets up to read from an echo server:

（来自该教程）这设置为从echo服务器读取：

    echoSocket = new Socket("taranis", 7);
    out = new PrintWriter(echoSocket.getOutputStream(), true);
    in = new BufferedReader(new InputStreamReader(
                                echoSocket.getInputStream()));

taking a stream of bytes and converts to strings via the reader and using a default encoding (not advisable, normally).

获取字节流并通过阅读器转换为字符串并使用默认编码（通常不建议）。

Error handling and closing sockets/streams omitted from the above, but check the tutorial.

从上面省略了错误处理和关闭套接字/流，但请查看教程。

#4

You need to either have the message be a fixed size, or you need to send the size or you need to use some separator characters.

您需要将消息设置为固定大小，或者需要发送大小，或者需要使用一些分隔符。

This is the easiest case for a known size (100 bytes):

对于已知大小（100字节），这是最简单的情况：

in = new DataInputStream(server.getInputStream());
byte[] message = new byte[100]; // the well known size
in.readFully(message);

In this case DataInputStream makes sense as it offers readFully(). If you don't use it, you need to loop yourself until the expected number of bytes is read.

在这种情况下，DataInputStream是有意义的，因为它提供了readFully（）。如果不使用它，则需要循环自己，直到读取预期的字节数。

#1