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1.byte uses 1 byte while int uses4 bytes. 2. integer literals like "45" are of byte int not byte. If you want a literal to be a byte, you have to cast it: "(byte)45". 3. When values are promoted as part of an expression or as parameters to a method call, they may be promoted to int, but never to byte. 4. Many parts of the Java language used int, but none of them use byte. For example, the length of an array is an int. /** * Convert an int to a byte array * * @param value int * @return byte[] */ public static byte[] intToByteArray(int value) { byte[] b = new byte[4]; for (int i = 0; i < 4; i++) { int offset = (b.length - 1 - i) * 8; b[i] = (byte) ((value >>> offset) & 0xFF); } return b; } /** * Convert the byte array to an int starting from the given offset. * * @param b The byte array * @param offset The array offset,如果byte數(shù)組長度就是4，則該值為0 * @return The integer */ public static int byteArrayToInt(byte[] b, int offset) { int value = 0; for (int i = 0; i < 4; i++) { int shift = (4 - 1 - i) * 8; value += (b[i + offset] & 0x000000FF) << shift; } return value; } |
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來自： cherishchen > 《java socket》
