最近做个通信项目使用UDP Socket,所以数据的接发都与byte[]有关,

基本类型与byte[]转换作为基础知识,需要mark一下. 0x0与0x00的区别是前者4位,后者8位.

ByteArrayOutputStream buf = new ByteArrayOutputStream();

DataOutputStream out = new DataOutputStream(buf);

out.writeShort(301);

byte[] b1 = buf.toByteArray();

for(byte bb : b1) {

System.out.print(Integer.toHexString(bb & 0xFF) + " ");

}

byte[] buf2 = {0x01,0x2d};

ByteArrayInputStream bintput = new ByteArrayInputStream(buf2);

DataInputStream dintput = new DataInputStream(bintput);

short i = dintput.readShort();

System.out.print(i);

//io的各种关闭省略..

 

如果把301定义成int,那么转换后byte[]的长度是4,内容是0x00 0x00 0x01 0x2d,因为int型占4byte32位,而short是2byte16位,同时注意取值范围.

 

public static int byte2ToUnsignedShort(byte[] bytes, int off) {

int high = bytes[off];

int low = bytes[off + 1];

return (high << 8 & 0xFF00) | (low & 0xFF);

}

public static byte[] unsignedShortToByte2(int s) {

byte[] targets = new byte[2];

targets[0] = (byte) (s >> 8 & 0xFF);

targets[1] = (byte) (s & 0xFF);

return targets;

}