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java怎么样将基本类型与字节流转化？Java基本类型转换成字节流
时间：2017-02-16 编辑：简简单单 来源：一聚教程网
简单的做了点Java 基本类型到字节的转换，测试了下，还能用... ...
这些主要是在用于网络通信的时候，对方如果传递给你一个字节流，里面包含的是基本类型的字节流，可以通过这个来转换成java 基本类型。
| 代码如下 | 复制代码 |
/** ** double转换byte * * @param arr * byte[] * * @param param * double double类型的参数 * * @param index * int * */ public static void putDouble(byte[] arr, double param, int index) { int len = (index - 1) + 8; int arrLen = arr.length; boolean b = isOutOfArrLength(arrLen, len); // 判断当前数组长度是否大于转换的数组长度 Long l = Double.doubleToLongBits(param); if (b) { for (int i = 7; i >= 0; i--) { arr[index + i] = l.byteValue(); l = l >> 8; } } else { // 如果当前数组长度小于转换的数组长度，就根据index截取转换的数组元素 l = l >> (8 * index); for (int j = arrLen - index - 1; j >= 0; j--) { arr[index + j] = l.byteValue(); l = l >> 8; } } } /** * * float转换byte * * * * @param arr * byte[] * * @param param * float float类型的参数 * * @param index * int * */ public static void putFloat(byte[] arr, float param, int index) { int len = (index - 1) + 4; int arrLen = arr.length; boolean b = isOutOfArrLength(arrLen, len); // 判断当前数组长度是否大于转换的数组长度 int l = Float.floatToIntBits(param); if (b) { for (int i = 3; i >= 0; i--) { arr[index + i] = new Integer(l).byteValue(); l = l >> 8; } } else { // 如果当前数组长度小于转换的数组长度，就根据index截取转换的数组元素 l = l >> (8 * index); for (int j = arrLen - index - 1; j >= 0; j--) { arr[index + j] = new Integer(l).byteValue(); l = l >> 8; } } } /** * * 字符到字节转换 * * * * @param arr * byte[] * * @param ch * char char类型的参数 * * @param index * int * * @return * */ public static void putChar(byte[] arr, char ch, int index) { int len = (index - 1) + 4; boolean b = isOutOfArrLength(arr.length, len); // 判断当前数组长度是否大于转换的数组长度 if (b) { int temp = (int) ch; for (int i = 1; i >= 0; i--) { arr[index + i] = new Integer(temp & 0xff).byteValue(); temp = temp >> 8; } } } /** * * 转换long型为byte数组 * * * * @param arr * byte[] * * @param param * long * * @param index * int * */ public static void putLong(byte[] arr, long param, int index) { int len = (index - 1) + 8; int arrLen = arr.length; boolean b = isOutOfArrLength(arrLen, len); // 判断当前数组长度是否大于转换的数组长度 if (b) { arr[index + 0] = (byte) ((param >> 56) & 0xff); arr[index + 1] = (byte) ((param >> 48) & 0xff); arr[index + 2] = (byte) ((param >> 40) & 0xff); arr[index + 3] = (byte) ((param >> 32) & 0xff); arr[index + 4] = (byte) ((param >> 24) & 0xff); arr[index + 5] = (byte) ((param >> 16) & 0xff); arr[index + 6] = (byte) ((param >> 8) & 0xff); arr[index + 7] = (byte) (param & 0xff); } else { // 如果当前数组长度小于转换的数组长度，就根据index截取转换的数组元素 param = param >> (8 * index); for (int i = arrLen - index - 1; i >= 0; i--) { arr[index + i] = (byte) (param & 0xff); param = param >> 8; } } } /** * * int类型转换成byte数组 * * * * @param arr * byte[] * * @param param * int int类型的参数 * * @param index * int * */ public static void putInt(byte[] arr, int param, int index) { int len = (index - 1) + 4; boolean b = isOutOfArrLength(arr.length, len); // 判断当前数组长度是否大于转换的数组长度 if (b) { arr[index + 0] = (byte) ((param >> 24) & 0xff); arr[index + 1] = (byte) ((param >> 16) & 0xff); arr[index + 2] = (byte) ((param >> 8) & 0xff); arr[index + 3] = (byte) (param & 0xff); } } /** * * short类型转换成byte数组 * * * * @param arr * byte[] * * @param param * short * * @param index * int * */ public static void putShort(byte[] arr, short param, int index) { int len = (index - 1) + 2; boolean b = isOutOfArrLength(arr.length, len); // 判断当前数组长度是否大于转换的数组长度 if (b) { arr[index + 0] = (byte) ((param >> 8) & 0xff); arr[index + 1] = (byte) (param & 0xff); } } /** * * 字符串转换成byte数组 * * * * @param arr * byte[] * * @param str * String * * @param index * int * * @throws java.io.UnsupportedEncodingException * */ public static void putString(byte[] arr, String str, int index) { try { byte[] bb = str.getBytes("GBK"); int len = index + bb.length; boolean b = isOutOfArrLength(arr.length, len); if (b) { for (int i = 0; i < bb.length; i++) { arr[index + i] = bb[i]; } } else { // 如果当前数组长度小于转换的数组长度，就根据index截取转换的数组元素 for (int j = 0; j < arr.length - index; j++) { arr[index + j] = bb[j]; } } } catch (Exception e) { e.printStackTrace(); } } /** * * 判断数组下标是否越界 * * * * @param arrLength * * 数组总长度 * * @param index * * 数组偏移量 * * @return * */ public static boolean isOutOfArrLength(int arrLength, int index) { boolean b; if (arrLength > index) { b = true; } else { b = false; } return b; } // long类型转成byte数组 public static byte[] longToBytes(long number) { long temp = number; byte[] b = new byte[8]; //long型是8个字节. for (int i = 0; i < b.length; i++) { b[i] = new Long(temp & 0xff).byteValue();// 将最低位保存在最低位 temp = temp >> 8; // 向右移8位 } return b; } // byte数组转成long public static long bytesToLong(byte[] b) { long s = 0; long s0 = b[0] & 0xff;// 最低位 long s1 = b[1] & 0xff; long s2 = b[2] & 0xff; long s3 = b[3] & 0xff; long s4 = b[4] & 0xff;// 最低位 long s5 = b[5] & 0xff; long s6 = b[6] & 0xff; long s7 = b[7] & 0xff; // s0不变 s1 <<= 8; s2 <<= 16; s3 <<= 24; s4 <<= 8 * 4; s5 <<= 8 * 5; s6 <<= 8 * 6; s7 <<= 8 * 7; s = s0 | s1 | s2 | s3 | s4 | s5 | s6 | s7; return s; } //int 转换为byte public static byte[] intToBytes(int number) { int temp = number; byte[] b = new byte[4]; for (int i = 0; i < b.length; i++) { b[i] = new Integer(temp & 0xff).byteValue();// 将最低位保存在最低位 temp = temp >> 8; // 向右移8位 } return b; } //字节转int public static int bytesToInt(byte[] b) { int s = 0; int s0 = b[0] & 0xff;// 最低位 int s1 = b[1] & 0xff; int s2 = b[2] & 0xff; int s3 = b[3] & 0xff; s3 <<= 24; s2 <<= 16; s1 <<= 8; s = s0 | s1 | s2 | s3; return s; } // 浮点到字节转换 public static byte[] doubleToBytes(double d) { byte writeBuffer[] = new byte[8]; long v = Double.doubleToLongBits(d); writeBuffer[0] = (byte) (v >>> 56); writeBuffer[1] = (byte) (v >>> 48); writeBuffer[2] = (byte) (v >>> 40); writeBuffer[3] = (byte) (v >>> 32); writeBuffer[4] = (byte) (v >>> 24); writeBuffer[5] = (byte) (v >>> 16); writeBuffer[6] = (byte) (v >>> 8); writeBuffer[7] = (byte) (v >>> 0); return writeBuffer; } // 字节到浮点转换 public static double bytesToDouble(byte[] readBuffer) { return Double .longBitsToDouble((((long) readBuffer[0] << 56) + ((long) (readBuffer[1] & 255) << 48) + ((long) (readBuffer[2] & 255) << 40) + ((long) (readBuffer[3] & 255) << 32) + ((long) (readBuffer[4] & 255) << 24) + ((readBuffer[5] & 255) << 16) + ((readBuffer[6] & 255) << 8) + ((readBuffer[7] & 255) << 0))); }
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更多的转换，可以通过实践去获得。
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