int、char、double与byte相互转换

public class ParseTest {// 整数到字节数组的转换public static byte[] intToByte(int number) {int temp = number;byte[] b = new byte[4];for (int i = b.length - 1; i > -1; i--) {b[i] = new Integer(temp & 0xff).byteValue(); // 将最高位保存在最低位temp = temp >> 8; // 向右移8位}return b;}// 字节数组到整数的转换public static int byteToInt(byte[] b) {int s = 0;for (int i = 0; i < 3; i++) {if (b[i] >= 0)s = s + b[i];elses = s + 256 + b[i];s = s * 256;}if (b[3] >= 0) // 最后一个之所以不乘，是因为可能会溢出s = s + b[3];elses = s + 256 + b[3];return s;}// 字符到字节转换public static byte[] charToByte(char ch) {int temp = (int) ch;byte[] b = new byte[2];for (int i = b.length - 1; i > -1; i--) {b[i] = new Integer(temp & 0xff).byteValue(); // 将最高位保存在最低位temp = temp >> 8; // 向右移8位}return b;}// 字节到字符转换public static char byteToChar(byte[] b) {int s = 0;if (b[0] > 0)s += b[0];elses += 256 + b[0];s *= 256;if (b[1] > 0)s += b[1];elses += 256 + b[1];char ch = (char) s;return ch;}// 浮点到字节转换public static byte[] doubleToByte(double d) {byte[] b = new byte[8];long l = Double.doubleToLongBits(d);for (int i = 0; i < b.length; i++) {b[i] = new Long(l).byteValue();l = l >> 8;}return b;}// 字节到浮点转换public static double byteToDouble(byte[] b) {long l;l = b[0];l &= 0xff;l |= ((long) b[1] << 8);l &= 0xffff;l |= ((long) b[2] << 16);l &= 0xffffff;l |= ((long) b[3] << 24);l &= 0xffffffffl;l |= ((long) b[4] << 32);l &= 0xffffffffffl;l |= ((long) b[5] << 40);l &= 0xffffffffffffl;l |= ((long) b[6] << 48);l |= ((long) b[7] << 56);return Double.longBitsToDouble(l);}}