从Java程序向运行C的设备发送字节流 [英] Sending a byte stream from a java program to a device running C

问题描述

我正在使用支持小尾数字节顺序的设备。

I am working with a device that supports little endian byte order. How do I do this in Java?

我已经从十六进制数据创建了字节流，并将其写入套接字输出流。我应该以以下格式发送数据。

I have created a byte stream from the hex data and wrote it to the socket output stream. I am supposed to send data in the following format.

协议版本：0x0001

Protocol-Version: 0x0001

Request_Code：0x0011

Request_Code: 0x0011

Request_Size：0x00000008

Request_Size: 0x00000008

String s = "0001001100000008";
byte[] bytes = hexStringToByteArray(s);
socket.getOutputStream().write(bytes);

public static byte[] hexStringToByteArray(String s) {
    int len = s.length();
    byte[] data = new byte[len / 2];
    for (int i = 0; i < len; i += 2) {
        data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
            + Character.digit(s.charAt(i+1), 16));
    }
    return data;
} 

但是我没有从设备收到此请求的任何响应。我做错了吗？

I am however not receiving any response from the device for this request. Am I doing something wrong?

推荐答案

下面是一个使用ByteBuffer的示例。代码未经测试，因此请确保它对您有用。

Here's an example using a ByteBuffer. Code is untested so make sure it works for you.

ByteBuffer bb = new ByteBuffer.allocate( 1024 );

short version = 0x0001;
short request = 0x0011;
int size = 0x08;

bb.order( ByteOrder.LITTLE_ENDIAN );
bb.put( version );
bb.put( request );
bb.put( size );

socket.getChannel().write( bb );

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