java整型数与网络字节序的 byte[] 数组转换关系
程序员文章站
2022-07-12 19:22:37
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工作项目需要在
java
和
c/c++
之间进行
socket
通信,
socket
通信是以字节流或者字节包进行的,
socket
发送方须将数据转换为字节流或者字节包,而接收方则将字节流和字节包再转换回相应的数据类型。如果发送方和接收方都是同种语言,则一般只涉及到字节序的调整。而对于
java
和
c/c++
的通信,则情况就要复杂一些,主要是因为
java
中没有
unsigned
类型,并且
java
和
c
在某些数据类型上的长度不一致。
本文就是针对这种情况,整理了
java
数据类型和网络字节流或字节包
(
相当于
java
的
byte
数组
)
之间转换方法。实际上网上这方面的资料不少,但往往不全,甚至有些有错误,于是就花了点时间对
java
整型数和网络字节序的
byte[]
之间转换的各种情况做了一些验证和整理。整理出来的函数如下:
public class ByteConvert { /** * 长整形转byte数组 * * @param n * 长整形数字 * @return 转换后的数组 */ public static byte[] longToBytes(long n) { byte[] b = new byte[8]; b[7] = (byte) (n & 0xff); b[6] = (byte) (n >> 8 & 0xff); b[5] = (byte) (n >> 16 & 0xff); b[4] = (byte) (n >> 24 & 0xff); b[3] = (byte) (n >> 32 & 0xff); b[2] = (byte) (n >> 40 & 0xff); b[1] = (byte) (n >> 48 & 0xff); b[0] = (byte) (n >> 56 & 0xff); return b; } /** * 长整形转byte数组 * * @param n * 长整形数字 * @param array * 转换后的结果 * @param offset * 从第offset位开始转换 */ public static void longToBytes(long n, byte[] array, int offset) { array[7 + offset] = (byte) (n & 0xff); array[6 + offset] = (byte) (n >> 8 & 0xff); array[5 + offset] = (byte) (n >> 16 & 0xff); array[4 + offset] = (byte) (n >> 24 & 0xff); array[3 + offset] = (byte) (n >> 32 & 0xff); array[2 + offset] = (byte) (n >> 40 & 0xff); array[1 + offset] = (byte) (n >> 48 & 0xff); array[0 + offset] = (byte) (n >> 56 & 0xff); } /** * bytes 转 Long * * @param array * 要转换的byte * @return long长整形数字 */ public static long bytesToLong(byte[] array) { return ((((long) array[0] & 0xff) << 56) | (((long) array[1] & 0xff) << 48) | (((long) array[2] & 0xff) << 40) | (((long) array[3] & 0xff) << 32) | (((long) array[4] & 0xff) << 24) | (((long) array[5] & 0xff) << 16) | (((long) array[6] & 0xff) << 8) | (((long) array[7] & 0xff) << 0)); } /** * byte数组转长整形数字 * * @param array * 要转换的byte数组 * @param offset * 从第offset开始转换 * @return 转换后的长整形数字 */ public static long bytesToLong(byte[] array, int offset) { return ((((long) array[offset + 0] & 0xff) << 56) | (((long) array[offset + 1] & 0xff) << 48) | (((long) array[offset + 2] & 0xff) << 40) | (((long) array[offset + 3] & 0xff) << 32) | (((long) array[offset + 4] & 0xff) << 24) | (((long) array[offset + 5] & 0xff) << 16) | (((long) array[offset + 6] & 0xff) << 8) | (((long) array[offset + 7] & 0xff) << 0)); } public static byte[] intToBytes(int n) { byte[] b = new byte[4]; b[3] = (byte) (n & 0xff); b[2] = (byte) (n >> 8 & 0xff); b[1] = (byte) (n >> 16 & 0xff); b[0] = (byte) (n >> 24 & 0xff); return b; } public static void intToBytes(int n, byte[] array, int offset) { array[3 + offset] = (byte) (n & 0xff); array[2 + offset] = (byte) (n >> 8 & 0xff); array[1 + offset] = (byte) (n >> 16 & 0xff); array[offset] = (byte) (n >> 24 & 0xff); } /** * @param b * @return */ public static int bytesToInt(byte b[]) { return b[3] & 0xff | (b[2] & 0xff) << 8 | (b[1] & 0xff) << 16 | (b[0] & 0xff) << 24; } /** * byte 数组转 int * * @param b * byte数组 * @param offset * 从数组的第几位开始转 * @return 整形 */ public static int bytesToInt(byte b[], int offset) { return b[offset + 3] & 0xff | (b[offset + 2] & 0xff) << 8 | (b[offset + 1] & 0xff) << 16 | (b[offset] & 0xff) << 24; } /** * 无符号整形转数组 * * @param n * 要转换的整形 * @return byte数组 */ public static byte[] uintToBytes(long n) { byte[] b = new byte[4]; b[3] = (byte) (n & 0xff); b[2] = (byte) (n >> 8 & 0xff); b[1] = (byte) (n >> 16 & 0xff); b[0] = (byte) (n >> 24 & 0xff); return b; } public static void uintToBytes(long n, byte[] array, int offset) { array[3 + offset] = (byte) (n); array[2 + offset] = (byte) (n >> 8 & 0xff); array[1 + offset] = (byte) (n >> 16 & 0xff); array[offset] = (byte) (n >> 24 & 0xff); } public static long bytesToUint(byte[] array) { return ((long) (array[3] & 0xff)) | ((long) (array[2] & 0xff)) << 8 | ((long) (array[1] & 0xff)) << 16 | ((long) (array[0] & 0xff)) << 24; } public static long bytesToUint(byte[] array, int offset) { return ((long) (array[offset + 3] & 0xff)) | ((long) (array[offset + 2] & 0xff)) << 8 | ((long) (array[offset + 1] & 0xff)) << 16 | ((long) (array[offset] & 0xff)) << 24; } public static byte[] shortToBytes(short n) { byte[] b = new byte[2]; b[1] = (byte) (n & 0xff); b[0] = (byte) ((n >> 8) & 0xff); return b; } public static void shortToBytes(short n, byte[] array, int offset) { array[offset + 1] = (byte) (n & 0xff); array[offset] = (byte) ((n >> 8) & 0xff); } public static short bytesToShort(byte[] b) { return (short) (b[1] & 0xff | (b[0] & 0xff) << 8); } public static short bytesToShort(byte[] b, int offset) { return (short) (b[offset + 1] & 0xff | (b[offset] & 0xff) << 8); } public static byte[] ushortToBytes(int n) { byte[] b = new byte[2]; b[1] = (byte) (n & 0xff); b[0] = (byte) ((n >> 8) & 0xff); return b; } public static void ushortToBytes(int n, byte[] array, int offset) { array[offset + 1] = (byte) (n & 0xff); array[offset] = (byte) ((n >> 8) & 0xff); } public static int bytesToUshort(byte b[]) { return b[1] & 0xff | (b[0] & 0xff) << 8; } public static int bytesToUshort(byte b[], int offset) { return b[offset + 1] & 0xff | (b[offset] & 0xff) << 8; } public static byte[] ubyteToBytes(int n) { byte[] b = new byte[1]; b[0] = (byte) (n & 0xff); return b; } public static void ubyteToBytes(int n, byte[] array, int offset) { array[0] = (byte) (n & 0xff); } public static int bytesToUbyte(byte[] array) { return array[0] & 0xff; } public static int bytesToUbyte(byte[] array, int offset) { return array[offset] & 0xff; } // char 类型、 float、double 类型和 byte[] 数组之间的转换关系还需继续研究实现。 }
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