背景前一段模仿WhatsApp Business的核心功能做了一套商业号服务，为了让老外看起来亲切，因此其接口设计尽量与WhatsApp保持一致，因此可以将此接口设计share出来，通过该接口设计，大家可以了解到WhatsApp Business的核心功能及其对应的接口定义；尽管如此，一些地方的设计也有小差异，例如：WhatsApp直接使用手机号码定位用户，在这套设计中则借鉴了微信公众号OpenUserId的套路，另外为了安全考虑对真实userId又进行了加入应用ID因子的混淆，因此可以做到：同一个用户不同应用（订阅号）下的OpenUserId不同，OpenUserId实现参考如下：ByteUtilpackagecodec;importorg.apache.commons.lang3.ArrayUtils;/** * ByteUtil * * @author chenx */publicclassByteUtil{publicstaticfinalintONE_BYTE_INT_MAX_VALUE=127;publicstaticfinalintONE_BYTE_INT_MIN_VALUE=-128;publicstaticfinalintTIMESTAMP_BYTES=6;privatestaticfinalStringINPUT_BYTES_LENGTH_MUST_MORE_THAN="The input bytes.length must =";privatestaticfinalStringINPUT_BYTES_LENGTH_MUST_BE="The input bytes.length must be ";privateByteUtil(){}/** * timestampToSixBytes * * @param timestamp * @return */publicstaticbyte[]timestampToSixBytes(longtimestamp){byte[]data=newbyte[TIMESTAMP_BYTES];data[0]=(byte)(timestamp40);data[1]=(byte)(timestamp32);data[2]=(byte)(timestamp24);data[3]=(byte)(timestamp16);data[4]=(byte)(timestamp8);data[5]=(byte)(timestamp0);returndata;}/** * sixBytesToTimestamp * * @param bytes * @return */publicstaticlongsixBytesToTimestamp(byte[]bytes){if(ArrayUtils.isEmpty(bytes)||bytes.lengthTIMESTAMP_BYTES){thrownewIllegalArgumentException(INPUT_BYTES_LENGTH_MUST_MORE_THAN+TIMESTAMP_BYTES);}return(((long)(bytes[0]255)40)+((long)(bytes[1]255)32)+((long)(bytes[2]255)24)+((bytes[3]255)16)+((bytes[4]255)8)+((bytes[5]255)0));}/** * short2Bytes * * @param num * @return */publicstaticbyte[]short2Bytes(shortnum){byte[]bytes=newbyte[Short.BYTES];bytes[0]=(byte)(num8);bytes[1]=(byte)num;returnbytes;}/** * bytes2Short * * @param bytes * @return */publicstaticshortbytes2Short(byte[]bytes){if(ArrayUtils.isEmpty(bytes)||bytes.length!=Short.BYTES){thrownewIllegalArgumentException(INPUT_BYTES_LENGTH_MUST_BE+Short.BYTES);}return(short)((bytes[0]8)|(bytes[1]0xFF));}/** * int2Bytes * * @param num * @return */publicstaticbyte[]int2Bytes(intnum){byte[]byteNum=newbyte[Integer.BYTES];for(intix=0;ixInteger.BYTES;++ix){intoffset=32-(ix+1)*8;byteNum[ix]=(byte)((numoffset)0xff);}returnbyteNum;}/** * bytes2Int * * @param bytes * @return */publicstaticintbytes2Int(byte[]bytes){if(ArrayUtils.isEmpty(bytes)||bytes.length!=Integer.BYTES){thrownewIllegalArgumentException(INPUT_BYTES_LENGTH_MUST_BE+Integer.BYTES);}intnum=0;for(intix=0;ixInteger.BYTES;++ix){num=8;num|=(bytes[ix]0xff);}returnnum;}/** * long2Bytes * * @param num * @return */publicstaticbyte[]long2Bytes(longnum){byte[]byteNum=newbyte[Long.BYTES];for(intix=0;ixLong.BYTES;++ix){intoffset=64-(ix+1)*8;byteNum[ix]=(byte)((numoffset)0xff);}returnbyteNum;}/** * bytes2Long * * @param bytes * @return */publicstaticlongbytes2Long(byte[]bytes){if(ArrayUtils.isEmpty(bytes)||bytes.length!=Long.BYTES){thrownewIllegalArgumentException(INPUT_BYTES_LENGTH_MUST_BE+Long.BYTES);}longnum=0;for(intix=0;ixLong.BYTES;++ix){num=8;num|=(bytes[ix]0xff);}returnnum;}/** * mergeBytes * * @param arrays * @return */publicstaticbyte[]mergeBytes(byte[]...arrays){inttotalLength=0;for(byte[]array:arrays){totalLength+=array.length;}byte[]result=newbyte[totalLength];intcurrentIndex=0;for(byte[]array:arrays){System.arraycopy(array,0,result,currentIndex,array.length);currentIndex+=array.length;}returnresult;}/** * getBytesFromStart * * @param array * @param length * @return */publicstaticbyte[]getBytesFromStart(byte[]array,intlength){if(ArrayUtils.isEmpty(array)){thrownewIllegalArgumentException("the input bytes is empty!");}if(length=0){thrownewIllegalArgumentException("The length must 0!");}if(array.lengthlength){thrownewIllegalArgumentException("the input bytes.length must "+length+"!");}byte[]result=newbyte[length];System.arraycopy(array,0,result,0,length);returnresult;}/** * obfuscateBytes * * @param bytes * @param hashBytesLength */publicstaticvoidhashObfuscate(byte[]bytes,inthashBytesLength){if(hashBytesLength=0){thrownewIllegalArgumentException("invalid hashLength!");}if(ArrayUtils.isEmpty(bytes)||bytes.length=hashBytesLength){thrownewIllegalArgumentException("bytes.length = "+hashBytesLength);}intleftBytesSize=bytes.length-hashBytesLength;byte[]hashBytes=newbyte[hashBytesLength];byte[]leftBytes=new