简介下TLV:
PBOC基本信息数据采用TLV（tag-length-value）的表示方式，即每项由tag标签(T)，长度(L)和取值(V)构成。
标签：
tag标签的属性为bit，由16进制表示，占1～2个字节长度。若tag标签的第一个字节（注：字节排序方向为从左往右数(b8~b0)，第一个字节即为最左边的字节。bit排序规则同理。）的后四个bit为“1111”，则说明该tag占两个字节，例如“9F33”；否则占一个字节，例如“95”。b8和b7两位标识tag所属类别. 这个可以暂时不用理. b6决定当前的TLV数据是一个单一的数据和复合结构的数据. 复合的TLV是指value域里也包含一个或多个TLV, 类似嵌套的编码格式. b5~b1如果全为1，则说明这个tag下面还有一个子字节. 占两个字节, 否则tag占一个字节。
长度：
长度（即L本身）的属性也为bit，占1～3个字节长度。具体编码规则如下：
a)当L字段最左边字节的最左bit位（即bit8）为0，表示该L字段占一个字节，它的后续7个bit位（即bit7～bit1）表示取值的长度，采用二进制数表示取值长度的十进制数。
b)当L字段最左边字节的最左bit位（即bit8）为1，表示该L字段不止占一个字节，那么它到底占几个字节由该最左字节的后续7个bit位（即bit7～bit1）的十进制取值表示。例如，若最左字节为10000010，表示L字段除该字节外，后面还有两个字节。其后续字节的十进制取值表示取值的长度。
附: java版的TLV解析:
package com.example.yang.myapplication.ans8583;
import java.util.ArrayList;
import java.util.List;
import static com.example.yang.myapplication.ans8583.Easy8583Ans.bytesToHexString;
import static com.example.yang.myapplication.ans8583.Easy8583Ans.hexStringToBytes;
import static java.lang.System.arraycopy;
/**
* Created by yangyongzhen on 2018/07/07
* simple TLV format Analysis
* qq:534117529
*/
public class TlvAns {
class Tag{
String tag;
String length;
String value;
@Override
public String toString() {
return "Tag{"
"tag='" tag '''
", length='" length '''
", value='" value '''
'}';
}
}
Tag tag;
List<Tag> tags;
public TlvAns(){
tags = new ArrayList<>();
}
void printTags(List<Tag> tags){
for(Tag tag : tags){
System.out.println(tag.toString());
}
}
int pbocTlvAns( byte[] rxbuf, int rxsize )
{
int cout=0,n=0,num=0;
//===========================================TLV解析
while( cout < rxsize ) {
if( ( ( (rxbuf[cout]&0xff) & 0x1F ) == 0x1F ) ) {
//2字节Tag
if( ( (rxbuf[cout]&0xff) == 0xBF ) && ( (rxbuf[cout 1]&0xff) == 0x0C ) ) {
//=================================//模板
//模板里的数据还需要进一步解析
num = 0;
}
else {
//=================================//标签
num = 1;
}
tag = new Tag();
tag.tag = String .format("xx",(rxbuf[cout]&0xff),(rxbuf[cout 1]&0xff));
cout = 2;
if( ( (rxbuf[cout]&0xff) & 0x80 ) == 0x80 ) {
//=============================//长度为非1字节
switch( (rxbuf[cout]&0xff) & 0x7F ) {
//目前只处理最多2字节
case 1:
n = (rxbuf[cout 1]&0xff);
tag.length = String.format("xx",(rxbuf[cout]&0xff),(rxbuf[cout 1]&0xff));
cout = 2;
break;
case 2:
n = ( ( (rxbuf[cout 1]&0xff) << 8 ) & 0xFF00 ) | (rxbuf[cout 2]&0xff);
tag.length = String.format("xxx",rxbuf[cout]&0xff,rxbuf[cout 1]&0xff,rxbuf[cout 2]&0xff);
cout = 3;
break;
// case 3:
//n = ( ( rxbuf[cout 1] << 16 ) & 0xFF0000 ) | ( ( rxbuf[cout 2] << 8 ) & 0xFF00 ) | rxbuf[cout 3];
//cout = 4;
//break;
default:
//ErrMsg((U08*)"L解析错误rn",strlen("L解析错误rn") );
return 40;
}
}
else {
//=============================//长度为1字节
n = (rxbuf[cout]&0xff);
tag.length = String.format("x",n);
cout = 1;
}
byte[] buffer = new byte[n];
arraycopy(rxbuf,cout,buffer,0,n);
tag.value = bytesToHexString(buffer);
tags.add(tag);
if( num == 0 ) {
//=================================//模板
//模板里的数据还需要进一步解析
}
else {
//=================================//标签
cout = n;
}
}
else {
//1字节T
if( ( (rxbuf[cout]&0xff) >= 0x61 ) && ( (rxbuf[cout]&0xff) <= 0x7F ) )
{//=================================//模板
//模板里的数据还需要进一步解析
num = 0;
}
else if( ( (rxbuf[cout]&0xff) == 0x80 ) || ( (rxbuf[cout]&0xff) == 0xA5 ) ) {
//=================================//模板
//模板里的数据还需要进一步解析
num = 0;
}
else {
//=================================//标签
num = 1;
}
tag = new Tag();
tag.tag = String .format("x",(rxbuf[cout]&0xff));
cout ;
if( ( (rxbuf[cout]&0xff) & 0x80 ) == 0x80 ) {
//=============================//长度为非1字节
switch( (rxbuf[cout]&0xff) & 0x7F ) {
//目前只处理最多2字节
case 1:
n = (rxbuf[cout 1]&0xff);
tag.length = String.format("xx",(rxbuf[cout]&0xff),(rxbuf[cout 1]&0xff));
cout = 2;
break;
case 2:
n = ( ( rxbuf[cout 1] << 8 ) & 0xFF00 ) | rxbuf[cout 2];
tag.length = String.format("xxx",(rxbuf[cout]&0xff),(rxbuf[cout 1]&0xff),(rxbuf[cout 2]&0xff));
cout = 3;
break;
// case 3:
//n = ( ( rxbuf[cout 1] << 16 ) & 0xFF0000 ) | ( ( rxbuf[cout 2] << 8 ) & 0xFF00 ) | rxbuf[cout 3];
//cout = 4;
//break;
default:
//ErrMsg((U08*)"L解析错误rn",strlen("L解析错误rn") );
return 40;
}
}
else {
//=============================//长度为1字节
n = (rxbuf[cout]&0xff);
tag.length = String.format("x",n);
cout = 1;
}
byte[] buffer = new byte[n];
arraycopy(rxbuf,cout,buffer,0,n);
tag.value = bytesToHexString(buffer);
tags.add(tag);
if( num == 0 ) {
//=================================//模板
//模板里的数据还需要进一步解析
}
else {
//=================================//标签
cout = n;
}
}
}
return 0;
}
public static void main(String[] args) {
String hexstr = "776882027C009F3602004E57136212264200008234827D25062204329991635F9F101307010103A00000010A01000000000079B281999F2608DE242036EBF1B10B5F3401019F6C0220009F5D060000000000005F20142020202020202020202020202020202020202020";
byte[] hexdata = hexStringToBytes(hexstr);
TlvAns tlvAns = new TlvAns();
//开始解析:
tlvAns.pbocTlvAns(hexdata,hexdata.length);
//打印出解析结果:
tlvAns.printTags(tlvAns.tags);
}
}输出结果：
Tag{tag='77',length='68', value='82027c009f3602004e57136212264200008234827d25062204329991635f9f101307010103a00000010a01000000000079b281999f2608de242036ebf1b10b5f3401019f6c0220009f5d060000000000005f20142020202020202020202020202020202020202020'} Tag{tag='82', length='02', value='7c00'} Tag{tag='9f36', length='02', value='004e'} Tag{tag='57', length='13', value='6212264200008234827d25062204329991635f'} Tag{tag='9f10', length='13', value='07010103a00000010a01000000000079b28199'} Tag{tag='9f26', length='08', value='de242036ebf1b10b'} Tag{tag='5f34', length='01', value='01'} Tag{tag='9f6c', length='02', value='2000'} Tag{tag='9f5d', length='06', value='000000000000'} Tag{tag='5f20', length='14', value='2020202020202020202020202020202020202020'}
