字符串和base64的相互轉換--包含emjo表情轉換成base64

兩種方法：

說明：我是在微信小程序裏面用到的，有需要用的朋友自己修改一下哈。

1、方法一：重點轉換 emjo表情，漢字和英文基本不轉換；

用到的插件如下：

// 將其轉成 base64
// var base64={
var utf16toEntities=function(str) {
  var patt = /[\ud800-\udbff][\udc00-\udfff]/g; // 檢測utf16字符正則
  str = str.replace(patt, function (char) {
    var H, L, code;
    if (char.length === 2) {
      H = char.charCodeAt(0); // 取出高位
      L = char.charCodeAt(1); // 取出低位
      code = (H - 0xD800) * 0x400 + 0x10000 + L - 0xDC00; // 轉換算法
      return "&#" + code + ";";
    } else {
      return char;
    }
  });
  return str;
}
var uncodeUtf16=function(str) {
  var reg = /\&#.*?;/g;
  var result = str.replace(reg, function (char) {
    var H, L, code;
    if (char.length == 9) {
      code = parseInt(char.match(/[0-9]+/g));
      H = Math.floor((code - 0x10000) / 0x400) + 0xD800;
      L = (code - 0x10000) % 0x400 + 0xDC00;
      return unescape("%u" + H.toString(16) + "%u" + L.toString(16));
    } else {
      return char;
    }
  });
  return result;
}
// }
module.exports={
  utf16toEntities,
  uncodeUtf16
}

 

 引用這個文件，加解密方式如下：

var Base64 = require("../../utils/base64s.js");

var a='AKak47開心😊';

var b=Base64.utf16toEntities(a);//加密

var c= Base64.uncodeUtf16(b);//解密

console.log('a:'+a);//輸出
console.log('b:'+b);//輸出
console.log('c:'+c);//輸出

 輸出如下圖：

2、方式二：全部轉換成base64，但是將base64轉換回來的時候是ascii碼，需要二次轉換。

個人推薦第二種啊，第一種還是不太嚴謹。

用到的插件如下：

(function () {
  var BASE64_MAPPING = [
    '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', '+', '/'
  ];

	/**
	 *ascii convert to binary
	 */
  var _toBinary = function (ascii) {
    var binary = new Array();
    while (ascii > 0) {
      var b = ascii % 2;
      ascii = Math.floor(ascii / 2);
      binary.push(b);
    }
		/*
		var len = binary.length;
		if(6-len > 0){
			for(var i = 6-len ; i > 0 ; --i){
				binary.push(0);
			}
		}*/
    binary.reverse();
    return binary;
  };

	/**
	 *binary convert to decimal
	 */
  var _toDecimal = function (binary) {
    var dec = 0;
    var p = 0;
    for (var i = binary.length - 1; i >= 0; --i) {
      var b = binary[i];
      if (b == 1) {
        dec += Math.pow(2, p);
      }
      ++p;
    }
    return dec;
  };

	/**
	 *unicode convert to utf-8
	 */
  var _toUTF8Binary = function (c, binaryArray) {
    var mustLen = (8 - (c + 1)) + ((c - 1) * 6);
    var fatLen = binaryArray.length;
    var diff = mustLen - fatLen;
    while (--diff >= 0) {
      binaryArray.unshift(0);
    }
    var binary = [];
    var _c = c;
    while (--_c >= 0) {
      binary.push(1);
    }
    binary.push(0);
    var i = 0, len = 8 - (c + 1);
    for (; i < len; ++i) {
      binary.push(binaryArray[i]);
    }

    for (var j = 0; j < c - 1; ++j) {
      binary.push(1);
      binary.push(0);
      var sum = 6;
      while (--sum >= 0) {
        binary.push(binaryArray[i++]);
      }
    }
    return binary;
  };

  var __BASE64 = {
    /**
     *BASE64 Encode
     */
    encoder: function (str) {
      var base64_Index = [];
      var binaryArray = [];
      for (var i = 0, len = str.length; i < len; ++i) {
        var unicode = str.charCodeAt(i);
        var _tmpBinary = _toBinary(unicode);
        if (unicode < 0x80) {
          var _tmpdiff = 8 - _tmpBinary.length;
          while (--_tmpdiff >= 0) {
            _tmpBinary.unshift(0);
          }
          binaryArray = binaryArray.concat(_tmpBinary);
        } else if (unicode >= 0x80 && unicode <= 0x7FF) {
          binaryArray = binaryArray.concat(_toUTF8Binary(2, _tmpBinary));
        } else if (unicode >= 0x800 && unicode <= 0xFFFF) {//UTF-8 3byte
          binaryArray = binaryArray.concat(_toUTF8Binary(3, _tmpBinary));
        } else if (unicode >= 0x10000 && unicode <= 0x1FFFFF) {//UTF-8 4byte
          binaryArray = binaryArray.concat(_toUTF8Binary(4, _tmpBinary));
        } else if (unicode >= 0x200000 && unicode <= 0x3FFFFFF) {//UTF-8 5byte
          binaryArray = binaryArray.concat(_toUTF8Binary(5, _tmpBinary));
        } else if (unicode >= 4000000 && unicode <= 0x7FFFFFFF) {//UTF-8 6byte
          binaryArray = binaryArray.concat(_toUTF8Binary(6, _tmpBinary));
        }
      }

      var extra_Zero_Count = 0;
      for (var i = 0, len = binaryArray.length; i < len; i += 6) {
        var diff = (i + 6) - len;
        if (diff == 2) {
          extra_Zero_Count = 2;
        } else if (diff == 4) {
          extra_Zero_Count = 4;
        }
        //if(extra_Zero_Count > 0){
        //	len += extra_Zero_Count+1;
        //}
        var _tmpExtra_Zero_Count = extra_Zero_Count;
        while (--_tmpExtra_Zero_Count >= 0) {
          binaryArray.push(0);
        }
        base64_Index.push(_toDecimal(binaryArray.slice(i, i + 6)));
      }

      var base64 = '';
      for (var i = 0, len = base64_Index.length; i < len; ++i) {
        base64 += BASE64_MAPPING[base64_Index[i]];
      }

      for (var i = 0, len = extra_Zero_Count / 2; i < len; ++i) {
        base64 += '=';
      }
      return base64;
    },
    /**
     *BASE64  Decode for UTF-8 
     */
    decoder: function (_base64Str) {
      var _len = _base64Str.length;
      var extra_Zero_Count = 0;
      /**
       *計算在進行BASE64編碼的時候，補了幾個0
       */
      if (_base64Str.charAt(_len - 1) == '=') {
        //alert(_base64Str.charAt(_len-1));
        //alert(_base64Str.charAt(_len-2));
        if (_base64Str.charAt(_len - 2) == '=') {//兩個等號說明補了4個0
          extra_Zero_Count = 4;
          _base64Str = _base64Str.substring(0, _len - 2);
        } else {//一個等號說明補了2個0
          extra_Zero_Count = 2;
          _base64Str = _base64Str.substring(0, _len - 1);
        }
      }

      var binaryArray = [];
      for (var i = 0, len = _base64Str.length; i < len; ++i) {
        var c = _base64Str.charAt(i);
        for (var j = 0, size = BASE64_MAPPING.length; j < size; ++j) {
          if (c == BASE64_MAPPING[j]) {
            var _tmp = _toBinary(j);
            /*不足6位的補0*/
            var _tmpLen = _tmp.length;
            if (6 - _tmpLen > 0) {
              for (var k = 6 - _tmpLen; k > 0; --k) {
                _tmp.unshift(0);
              }
            }
            binaryArray = binaryArray.concat(_tmp);
            break;
          }
        }
      }

      if (extra_Zero_Count > 0) {
        binaryArray = binaryArray.slice(0, binaryArray.length - extra_Zero_Count);
      }

      var unicode = [];
      var unicodeBinary = [];
      for (var i = 0, len = binaryArray.length; i < len;) {
        if (binaryArray[i] == 0) {
          unicode = unicode.concat(_toDecimal(binaryArray.slice(i, i + 8)));
          i += 8;
        } else {
          var sum = 0;
          while (i < len) {
            if (binaryArray[i] == 1) {
              ++sum;
            } else {
              break;
            }
            ++i;
          }
          unicodeBinary = unicodeBinary.concat(binaryArray.slice(i + 1, i + 8 - sum));
          i += 8 - sum;
          while (sum > 1) {
            unicodeBinary = unicodeBinary.concat(binaryArray.slice(i + 2, i + 8));
            i += 8;
            --sum;
          }
          unicode = unicode.concat(_toDecimal(unicodeBinary));
          unicodeBinary = [];
        }
      }
      return unicode;
    }
  };

  //window.BASE64 = __BASE64;
  module.exports = {
    CusBASE64: __BASE64
  }
})();

 在頁面上的引用如下：

var CusBASE64 = require("../../utils/base64.js");

 var a = 'AKak47開心😊';

    var b = CusBASE64.CusBASE64.encoder(a);//加密
    var c = CusBASE64.CusBASE64.decoder(b);//解密

    console.log('a:'+a)
    console.log('b:'+b)
    console.log('c:'+c)

//二次轉換
    var reg =new RegExp('^([A-Za-z0-9+/]{4})*([A-Za-z0-9+/]{4}|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{2}==)$');
    var name = '';
    c.forEach(element => {
      name += String.fromCharCode(element);
    });
    console.log('name:'+name)//這裏的name==上面的a

頁面輸出如下：