第C＃實現(xiàn)Base64編碼與解碼及規(guī)則case1:result[blockCount*4-1]='=';break;

case2:result[blockCount*4-1]='=';

result[blockCount*4-2]='=';

break;

default:break;

returnnewstring(result);

privatecharsixbit2char(byteb)

char[]lookupTable=newchar[64]{

'A','B','C','D','E','F','G','H','I','J','K','L','M',

'N','O','P','Q','R','S','T','U','V','W','X','Y','Z',

'a','b','c','d','e','f','g','h','i','j','k','l','m',

'n','o','p','q','r','s','t','u','v','w','x','y','z',

'0','1','2','3','4','5','6','7','8','9','+','/'};

if((b=0)(b=63))

returnlookupTable[(int)b];

else

return'';

}

解碼類：

///summary

///Base64解碼類

///將Base64編碼的string類型轉(zhuǎn)換成byte[]類型

////summary

publicclassBase64Decoder

char[]source;

intlength,length2,length3;

intblockCount;

intpaddingCount;

publicstaticBase64DecoderDecoder=newBase64Decoder();

publicBase64Decoder()

privatevoidinit(char[]input)

inttemp=0;

source=input;

length=input.Length;

for(intx=0;xx++)

if(input[length-x-1]=='=')

temp++;

paddingCount=temp;

blockCount=length/4;

length2=blockCount*3;

publicbyte[]GetDecoded(stringstrInput)

//初始化

init(strInput.ToCharArray());

byte[]buffer=newbyte[length];

byte[]buffer2=newbyte[length2];

for(intx=0;xlength;x++)

buffer[x]=char2sixbit(source[x]);

byteb,b1,b2,b3;

bytetemp1,temp2,temp3,temp4;

for(intx=0;xblockCount;x++)

temp1=buffer[x*4];

temp2=buffer[x*4+1];

temp3=buffer[x*4+2];

temp4=buffer[x*4+3];

b=(byte)(temp12);

b1=(byte)((temp248)4);

b1+=b;

b=(byte)((temp215)4);

b2=(byte)((temp360)2);

b2+=b;

b=(byte)((temp33)6);

b3=temp4;

b3+=b;

buffer2[x*3]=b1;

buffer2[x*3+1]=b2;

buffer2[x*3+2]=b3;

length3=length2-paddingCount;

byte[]result=newbyte[length3];

for(intx=0;xlength3;x++)

result[x]=buffer2[x];

returnresult;

privatebytechar2sixbit(charc)

char[]lookupTable=newchar[64]{

'A','B','C','D','E','F','G','H','I','J','K','L','M','N',

'O','P','Q','R','S','T','U','V','W','X','Y','Z',

'a','b','c','d','e','f','g','h','i','j','k','l','m','n',

'o','p','q','r','s','t','u','v','w','x','y','z',

'0','1','2','3','4','5','6','7','8','9','+','/'};

if(c=='=')

return0;

for(intx=0;xx++)

if(lookupTable[x]==c)

return(byte)x;

return0;

//解碼類結(jié)束

提示：

上面的代碼只是說明base64編碼的原理，以便用更多語言重寫。但.net里面可以使用更簡單的方法：

編碼：

byte[]bytes=Encoding.Default.GetBytes("要轉(zhuǎn)換的字符串");

Convert.ToBase64String(bytes);

解碼：

//"ztKwrsTj"是