在 Java 中如何获得表示 unsigned int 的字节？

发布于 2024-10-24 11:15:50 字数 1179 浏览 2 评论 0原文

我有从 0 到 255 的整数，我需要将它们传递到编码为无符号字节的 OutputStream。我尝试使用像这样的掩码进行转换，但如果 i=1，我的流的另一端（需要 uint8_t 的串行设备）认为我已经发送了一个无符号整数 = 6。

OutputStream out;
public void writeToStream(int i) throws Exception {
    out.write(((byte)(i & 0xff)));
}

我正在与 Arduino 交谈/dev/ttyUSB0 使用 Ubuntu，如果这让事情或多或少变得有趣的话。

这是 Arduino 代码：

uint8_t nextByte() {
    while(1) {
    if(Serial.available() > 0) {
        uint8_t b =  Serial.read();
      return b;
     }
    }
}

我还有一些与 Arduino 代码配合得很好的 Python 代码，如果我在 Python 中使用此代码，Arduino 会很高兴地收到正确的整数：

class writerThread(threading.Thread): 
    def __init__(self, threadID, name):
        threading.Thread.__init__(self)
        self.threadID = threadID
        self.name = name
    def run(self):
        while True:
            input = raw_input("[W}Give Me Input!")
            if (input == "exit"):
               exit("Goodbye");
            print ("[W]You input %s\n" % input.strip())
            fval = [ int(input.strip()) ]
            ser.write("".join([chr(x) for x in fval]))

我最终也想在 Scala 中执行此操作，但我'在解决这个问题时，我回到了 Java 以避免复杂性。

原文

I have integers from 0 to 255, and I need to pass them along to an OutputStream encoded as unsigned bytes. I've tried to convert using a mask like so, but if i=1, the other end of my stream (a serial device expecting uint8_t) thinks I've sent an unsigned integer = 6.

OutputStream out;
public void writeToStream(int i) throws Exception {
    out.write(((byte)(i & 0xff)));
}

I'm talking to an Arduino at /dev/ttyUSB0 using Ubuntu if this makes things any more or less interesting.

Here's the Arduino code:

uint8_t nextByte() {
    while(1) {
    if(Serial.available() > 0) {
        uint8_t b =  Serial.read();
      return b;
     }
    }
}

I also have some Python code that works great with the Arduino code, and the Arduino happily receives the correct integer if I use this code in Python:

class writerThread(threading.Thread): 
    def __init__(self, threadID, name):
        threading.Thread.__init__(self)
        self.threadID = threadID
        self.name = name
    def run(self):
        while True:
            input = raw_input("[W}Give Me Input!")
            if (input == "exit"):
               exit("Goodbye");
            print ("[W]You input %s\n" % input.strip())
            fval = [ int(input.strip()) ]
            ser.write("".join([chr(x) for x in fval]))

I'd also eventually like to do this in Scala, but I'm falling back to Java to avoid the complexity while I solve this issue.

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