公司内部有些C#服务使用proto-net，引入了bcl.proto中的bcl.Decimal、bcl.DateTime等。对于java的proto生成代码需要对bcl.Decimal、bcl.DateTime转换成本地支持的数据类型。
bcl.Decimal结构为32位int保存高位、64位long保存低位，signScale 保存符号（正负）及模数。转换过程如下：
bcl.Decimal --> BigDecimal
1. 将高32位的int以高位在前格式转换为4个长度的byte数组；
2. 将低64位的long以高位在前的格式转换为8个长度的byte数组；
3. 将两个数组组合为12长度的byte数组bigIntBytes，获取signScale的符号值sgin = (signScale & 1) == 1 ? -1 : 1; (参考bcl.Decimal 注释：the number of decimal digits (bits 1-16), and the sign (bit 0))
4. 根据bigIntBytes和sgin获取BigInteger对象bInt，new BigInteger(sgin，bigIntBytes);
5. 获取signScale的模数值scale = (signScale & 0b1111_1111_1111_1110) >> 1; (参考bcl.Decimal 注释：the number of decimal digits (bits 1-16), and the sign (bit 0))
6.根据bInt和scale获取BigDecimal对象，new BigDecimal(bint, scale);
BigDecimal --> bcl.Decimal
上述过程反之即可
代码如下：
/*JDK1.7*/
public class BclUtil {
/**
*
*/
private static final long TICKS_PER_MILLISECOND = 10000; private static final int SIGNSCALE_FLAG = 0b1111_1111_1111_1110; private BclUtil() { } /**
* 转换 bcl.Decimal，返回BigDecimal<br>
* 高位在前<br>
*
* @param bclDecimal
* @return
*/
public final static BigDecimal bclDecimalToBigDecimal(Bcl.Decimal bclDecimal) {
if (bclDecimal == null) {
return BigDecimal.ZERO;
}
byte[] deBytes = new byte[12];
int2byte(deBytes, 0, bclDecimal.getHi());
long2byte(deBytes, 4, bclDecimal.getLo());
int signScale = bclDecimal.getSignScale();
BigInteger bint = new BigInteger(getSign(signScale), deBytes);
return new BigDecimal(bint, getScale(signScale));
} /**
* 转换BigDecimal，返回bcl.Decimal<br>
* 高位在前<br>
*
* @param bigDecimal
* @return
*/
public final static Bcl.Decimal bigDecimalToBclDecimal(BigDecimal bigDecimal) {
if (bigDecimal == null) {
return null;
}
Bcl.Decimal.Builder b = Bcl.Decimal.newBuilder();
// 获取BigInteger,必须是unscaledValue
BigInteger bi = bigDecimal.unscaledValue();
byte[] deBytes = new byte[12];
byte[] bigIntegerBytes = bi.toByteArray();
System.arraycopy(bigIntegerBytes, 0, deBytes, 12 - bigIntegerBytes.length, bigIntegerBytes.length);
// 取高4位int
int hi = Eutil.bytes2int(deBytes, 0);
b.setHi(hi);
// 取低8位long
long lo = Eutil.bytes2long(deBytes, 4);
b.setLo(lo);
int signScale = getSignScale(bi.signum(), bigDecimal.scale());
b.setSignScale(signScale);
return b.build();
} private static int getSignScale(int signum, int scale) {
// 从BigInteger获取取标志位放在bit 0/从BigDecimal获取取标志位放在bit 1-16
return getSignInSignScale(signum) | (scale << 1);
} public final static Bcl.Decimal zeroOfBclDecimal() {
Bcl.Decimal.Builder b = Bcl.Decimal.newBuilder();
b.setHi(0);
b.setLo(0);
b.setSignScale(0);
return b.build();
} /**
* 填充值符号<br>
*
* @param sign
* @return
*/
public final static byte getSignInSignScale(int sign) {
byte signTemp = 0;
if (sign < 0) {
signTemp = 1;
}
return signTemp;
} /**
* 获取值符号<br>
*
* @param signScale
* @return
*/
public final static int getSign(int signScale) {
// the number of decimal digits (bits 1-16), and the sign (bit 0)
boolean isNegative = (signScale & 1) == 1;
return isNegative ? -1 : 1;
} /**
* 获取模数
*
* @param signScale
* @return
*/
public final static int getScale(int signScale) {
// the number of decimal digits (bits 1-16), and the sign (bit 0)
return (signScale & SIGNSCALE_FLAG) >> 1;
} /**
* 获取int的byte数组，高位在前
*
* @param dst
* @param pos
* @param src
*/
public final static void int2byte(byte[] dst, int pos, int src) {
int2byte(dst, pos, src, true);
} public final static byte[] int2byte(byte[] dst, int pos, int src, boolean big_endian) {
if (big_endian) {
dst[pos + 3] = (byte) ((src >>> 0) & 0xff);
dst[pos + 2] = (byte) ((src >>> 8) & 0xff);
dst[pos + 1] = (byte) ((src >>> 16) & 0xff);
dst[pos + 0] = (byte) ((src >>> 24) & 0xff);
} else {
dst[pos + 0] = (byte) ((src >>> 0) & 0xff);
dst[pos + 1] = (byte) ((src >>> 8) & 0xff);
dst[pos + 2] = (byte) ((src >>> 16) & 0xff);
dst[pos + 3] = (byte) ((src >>> 24) & 0xff);
} return dst;
} public final static byte[] int2unSignByte(byte[] dst, int pos, int src, boolean big_endian) {
if (big_endian) {
dst[pos + 3] = (byte) ((src >>> 0) & 0xff + 128);
dst[pos + 2] = (byte) ((src >>> 8) & 0xff + 128);
dst[pos + 1] = (byte) ((src >>> 16) & 0xff + 128);
dst[pos + 0] = (byte) ((src >>> 24) & 0xff + 128);
} else {
dst[pos + 0] = (byte) ((src >>> 0) & 0xff + 128);
dst[pos + 1] = (byte) ((src >>> 8) & 0xff + 128);
dst[pos + 2] = (byte) ((src >>> 16) & 0xff + 128);
dst[pos + 3] = (byte) ((src >>> 24) & 0xff + 128);
} return dst;
} /**
* 获取long的byte数组，高位在前
*
* @param dst
* @param pos
* @param src
*/
final static void long2byte(byte[] dst, int pos, long src) {
long2byte(dst, pos, src, true);
} final static void long2byte(byte[] dst, int pos, long src, boolean big_endian) {
if (big_endian) {
int2byte(dst, 4 + pos, (int) (src & 0xffffffff));
int2byte(dst, 0 + pos, (int) ((src >>> 32) & 0xffffffff));
} else {
int2byte(dst, 0 + pos, (int) (src & 0xffffffff));
int2byte(dst, 4 + pos, (int) ((src >>> 32) & 0xffffffff));
}
}
}