BitConverter.java：位处理字节数组处理工具类
字节处理工具类，可以从byte\[\]数组中读取Int16，Int32，Int64，以及int或long与byte\[\]数组的相互转换。
```
package com.itshidu.util;
/**
* 位处理，字节处理
* @author Master.Xia Date:2017年12月15日
*/
public class BitConverter {
public static short ToInt16(byte[] bytes, int offset) {
short result = (short) ((int)bytes[offset]&0xff);
result &##124;= ((int)bytes[offset+1]&0xff) << 8;
return (short) (result & 0xffff);
}
public static int ToUInt16(byte[] bytes, int offset) {
int result = (int)bytes[offset+1]&0xff;
result &##124;= ((int)bytes[offset]&0xff) << 8;
return result & 0xffff;
}
public static int ToInt32(byte[] bytes, int offset) {
int result = (int)bytes[offset]&0xff;
result &##124;= ((int)bytes[offset+1]&0xff) << 8;
result &##124;= ((int)bytes[offset+2]&0xff) << 16;
result &##124;= ((int)bytes[offset+3]&0xff) << 24;
return result;
}
public static long ToUInt32(byte[] bytes, int offset) {
long result = (int)bytes[offset]&0xff;
result &##124;= ((int)bytes[offset+1]&0xff) << 8;
result &##124;= ((int)bytes[offset+2]&0xff) << 16;
result &##124;= ((int)bytes[offset+3]&0xff) << 24;
return result & 0xFFFFFFFFL;
}
public static long ToInt64(byte[] buffer,int offset) {
long values = 0;
for (int i = 0; i < 8; i++) {
values <<= 8; values &##124;= (buffer[offset+i] & 0xFF);
}
return values;
}
public static long ToUInt64(byte[] bytes, int offset) {
long result = 0;
for (int i = 0; i <= 56; i += 8) {
result &##124;= ((int)bytes[offset++]&0xff) << i;
}
return result;
}
public static float ToFloat(byte[] bs, int index) {
return Float.intBitsToFloat(ToInt32(bs, index));
}
public static double ToDouble(byte[] arr,int offset) {
return Double.longBitsToDouble(ToUInt64(arr, offset));
}
public static boolean ToBoolean(byte[] bytes,int offset) {
return (bytes[offset]==0x00)? false:true;
}
public static byte[] GetBytes(short value) {
byte[] bytes = new byte[2];
bytes[0] = (byte) (value & 0xff);
bytes[1] = (byte) ((value & 0xff00) >> 8);
return bytes;
}
public static byte[] GetBytes(int value) {
byte[] bytes = new byte[4];
bytes[0] = (byte) ((value)&0xFF); //最低位
bytes[1] = (byte) ((value >> 8)&0xFF);
bytes[2] = (byte) ((value >> 16)&0xFF);
bytes[3] = (byte) ((value >>> 24)); //最高位，无符号右移
return bytes;
}
public static byte[] GetBytes(long values) {
byte[] buffer = new byte[8];
for (int i = 0; i < 8; i++) {
int offset = 64 - (i + 1) * 8;
buffer[i] = (byte)((values >> offset) & 0xff);
}
return buffer;
}
public static byte[] GetBytes(float value) {
return GetBytes(Float.floatToIntBits(value));
}
public static byte[] GetBytes(double val) {
long value = Double.doubleToLongBits(val);
return GetBytes(value);
}
public static byte[] GetBytes(boolean value) {
return new byte[]{(byte)(value? 1:0)};
}
public static byte IntToByte(int x) {
return (byte) x;
}
public static int ByteToInt(byte b) {
return b & 0xFF;
}
public static char ToChar(byte[] bs,int offset) {
return (char) (((bs[offset] & 0xFF) << 8) &##124; (bs[offset+1] & 0xFF));
}
public static byte[] GetBytes(char value) {
byte[] b = new byte[2];
b[0] = (byte) ((value & 0xFF00) >> 8);
b[1] = (byte) (value & 0xFF);
return b;
}
public static byte[] Concat(byte[]... bs) {
int len = 0,idx=0;
for(byte[] b:bs)len+=b.length;
byte[] buffer = new byte[len];
for(byte[] b:bs) {
System.arraycopy(b,0, buffer, idx, b.length);
idx+=b.length;
}
return buffer;
}
public static void main(String[] args) {
long a = 123456;
byte[] b1=GetBytes(a);
long b= ToInt64(b1, 0);
System.out.println(b);
}
}
```