Java Map小结以及前后端加密传输

1、通过采用 LinkedHashMap 将 list 中按照指定的 key 进行分组排序（HashMap 会乱序）

public LinkedHashMap<String,List<XqPersonTransfer>> qryHistoryEventList() {
        LinkedHashMap<String, List<XqPersonTransfer>> resultMap = new LinkedHashMap<>(100);

        List<XqPersonTransfer> resultList = xqPersonTransferMapper.qryHistoryEventList();
        if(resultList != null && resultList.size()>0){
            try{
               for(XqPersonTransfer xqPersonTransfer : resultList){
                    //map中eventId已存在，将该数据存放到同一个key（key指的就是eventId）的map中
                    if(resultMap.containsKey(xqPersonTransfer.getEventId().toString())){
                        resultMap.get(xqPersonTransfer.getEventId().toString()).add(xqPersonTransfer);
                    }else{//map中不存在，新建key，用来存放数据
                        List<XqPersonTransfer> tmpList = new ArrayList<XqPersonTransfer>();
                        tmpList.add(xqPersonTransfer);
                        resultMap.put(xqPersonTransfer.getEventId().toString(), tmpList);

                    }
                }


            }catch(Exception e){
                try {
                    throw new Exception("按照eventID对数据进行分组时出现异常", e);
                } catch (Exception e1) {
                    logger.error(e.getMessage(),e);
                }
            }
        }
        return resultMap;
    }

2、关于避免抓包前后端加密传输一些敏感信息

• 前端 JS base64 加密算法

var keyStr =
  "ABCDEFGHIJKLMNOP" +
  "QRSTUVWXYZabcdef" +
  "ghijklmnopqrstuv" +
  "wxyz0123456789+/" +
  "=";
function encode64(input) {
  var output = "";
  var chr1,
    chr2,
    chr3 = "";
  var enc1,
    enc2,
    enc3,
    enc4 = "";
  var i = 0;
  do {
    chr1 = input.charCodeAt(i++);
    chr2 = input.charCodeAt(i++);
    chr3 = input.charCodeAt(i++);
    enc1 = chr1 >> 2;
    enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
    enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
    enc4 = chr3 & 63;
    if (isNaN(chr2)) {
      enc3 = enc4 = 64;
    } else if (isNaN(chr3)) {
      enc4 = 64;
    }
    output =
      output +
      keyStr.charAt(enc1) +
      keyStr.charAt(enc2) +
      keyStr.charAt(enc3) +
      keyStr.charAt(enc4);
    chr1 = chr2 = chr3 = "";
    enc1 = enc2 = enc3 = enc4 = "";
  } while (i < input.length);

  return output;
}

• 后端 Java 解密算法

public static String decode(String str) {
        byte[] base64DecodeChars = new byte[] { -1, -1, -1, -1, -1,
                -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
                -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
                -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59,
                60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
                10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1,
                -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37,
                38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1,
                -1, -1 };

        byte[] data = str.getBytes();
        int len = data.length;
        ByteArrayOutputStream buf = new ByteArrayOutputStream(len);
        int i = 0;
        int b1, b2, b3, b4;

        while (i < len) {
            do {
                b1 = base64DecodeChars[data[i++]];
            } while (i < len && b1 == -1);
            if (b1 == -1) {
                break;
            }

            do {
                b2 = base64DecodeChars[data[i++]];
            } while (i < len && b2 == -1);
            if (b2 == -1) {
                break;
            }
            buf.write((int) ((b1 << 2) | ((b2 & 0x30) >>> 4)));

            do {
                b3 = data[i++];
                if (b3 == 61) {
                    return new String(buf.toByteArray());
                }
                b3 = base64DecodeChars[b3];
            } while (i < len && b3 == -1);
            if (b3 == -1) {
                break;
            }
            buf.write((int) (((b2 & 0x0f) << 4) | ((b3 & 0x3c) >>> 2)));

            do {
                b4 = data[i++];
                if (b4 == 61) {
                    return new String(buf.toByteArray());
                }
                b4 = base64DecodeChars[b4];
            } while (i < len && b4 == -1);
            if (b4 == -1) {
                break;
            }
            buf.write((int) (((b3 & 0x03) << 6) | b4));
        }
        return new String(buf.toByteArray());
    }