长url变成短url

- 日理万妓 2023-07-07 08:15 18阅读 0赞

package com.xxxx.xclouddesk.utils;
    
    
    import java.security.MessageDigest;
    import java.util.HashMap;
    import java.util.Map;
    import java.util.concurrent.atomic.AtomicLong;
    
    import static com.alibaba.fastjson.util.IOUtils.DIGITS;
    
    public class ShorUrlUtils { 
    
        private AtomicLong sequence = new AtomicLong(0);
    
        //十六进制下数字到字符的映射数组
        private final static String[] hexDigits = { "0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F"};
    
        public static final char[] array =
                { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
                        'q', 'w', 'e', 'r', 't', 'y', 'u', 'i', 'o', 'p', 'a', 's', 'd',
                        'f', 'g', 'h', 'j', 'k', 'l', 'z', 'x', 'c', 'v', 'b', 'n', 'm',
                        'Q', 'W', 'E', 'R', 'T', 'Y', 'U', 'I', 'O', 'P', 'A', 'S', 'D',
                        'F', 'G', 'H', 'J', 'K', 'L', 'Z', 'X', 'C', 'V', 'B', 'N', 'M'};
    
        public static Map<Character, Integer> charValueMap = new HashMap<Character, Integer>();
    
        //初始化map
        static { 
            for (int i = 0; i < array.length; i++) { 
                charValueMap.put(array[i], i);
            }
        }
    
    
        /** * 将 长数字转成端url * @param args */
        public static void main(String[] args) { 
            for (int i = 0; i < 100; i++) { 
                long number = Long.MAX_VALUE - i;
                String decimalStr = numberConvertToDecimal(number, 62);
                System.out.println(number + " 转换成 " + decimalStr);
                long toNumber = decimalConvertToNumber(decimalStr, 62);
                System.out.println(decimalStr + " 转换成 " + toNumber);
            }
        }
    
    
        /** * 生成短url * @param url * @return */
        public static String[] shortUrl(String url) { 
            // 可以自定义生成 MD5 加密字符传前的混合 KEY
            String key = "short_url";
            // 要使用生成 URL 的字符
            String[] chars = new String[]{ "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", "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"
            };
            // 对传入网址进行 MD5 加密
            String sMD5EncryptResult = (md5(key + url));
            String hex = sMD5EncryptResult;
            String[] resUrl = new String[4];
            //得到 4组短链接字符串
            for (int i = 0; i < 4; i++) { 
                // 把加密字符按照 8 位一组 16 进制与 0x3FFFFFFF 进行位与运算
                String sTempSubString = hex.substring(i * 8, i * 8 + 8);
                // 这里需要使用 long 型来转换，因为 Inteper .parseInt() 只能处理 31 位 , 首位为符号位 , 如果不用 long ，则会越界
                long lHexLong = 0x3FFFFFFF & Long.parseLong(sTempSubString, 16);
                String outChars = "";
                //循环获得每组6位的字符串
                for (int j = 0; j < 6; j++) { 
                    // 把得到的值与 0x0000003D 进行位与运算，取得字符数组 chars 索引(具体需要看chars数组的长度 以防下标溢出，注意起点为0)
                    long index = 0x0000003D & lHexLong;
                    // 把取得的字符相加
                    outChars += chars[(int) index];
                    // 每次循环按位右移 5 位
                    lHexLong = lHexLong >> 5;
                }
                // 把字符串存入对应索引的输出数组
                resUrl[i] = outChars;
            }
            return resUrl;
        }
    
    
    
        /**把inputString加密*/
        public static String md5(String inputStr){ 
            return encodeByMD5(inputStr);
        }
    
        /** * 验证输入的密码是否正确 * @param password 真正的密码（加密后的真密码） * @param inputString 输入的字符串 * @return 验证结果，boolean类型 */
        public static boolean authenticatePassword(String password,String inputString){ 
            if(password.equals(encodeByMD5(inputString))){ 
                return true;
            }else{ 
                return false;
            }
        }
    
        /**对字符串进行MD5编码*/
        private static String encodeByMD5(String originString){ 
            if (originString!=null) { 
                try { 
                    //创建具有指定算法名称的信息摘要
                    MessageDigest md5 = MessageDigest.getInstance("MD5");
                    //使用指定的字节数组对摘要进行最后更新，然后完成摘要计算
                    byte[] results = md5.digest(originString.getBytes());
                    //将得到的字节数组变成字符串返回
                    String result = byteArrayToHexString(results);
                    return result;
                } catch (Exception e) { 
                    e.printStackTrace();
                }
            }
            return null;
        }
    
        /** * 轮换字节数组为十六进制字符串 * @param b 字节数组 * @return 十六进制字符串 * */
        private static String byteArrayToHexString(byte[] b){ 
            StringBuffer resultSb = new StringBuffer();
            for(int i=0;i<b.length;i++){ 
                resultSb.append(byteToHexString(b[i]));
            }
            return resultSb.toString();
        }
    
        //将一个字节转化成十六进制形式的字符串
        private static String byteToHexString(byte b){ 
            int n = b;
            if(n<0) { 
                n=256+n;
            }
            int d1 = n/16;
            int d2 = n%16;
            return hexDigits[d1] + hexDigits[d2];
        }
    
        /** * 把数字转换成相对应的进制,目前支持(2-62)进制 * * @param number * @param decimal * @return */
        public static String numberConvertToDecimal(long number, int decimal) { 
            StringBuilder builder = new StringBuilder();
            while (number != 0) { 
                builder.append(array[(int) (number - (number / decimal) * decimal)]);
                number /= decimal;
            }
            return builder.reverse().toString();
        }
    
        /** * 把进制字符串转换成相应的数字 * @param decimalStr * @param decimal * @return */
        public static long decimalConvertToNumber(String decimalStr, int decimal) { 
            long sum = 0;
            long multiple = 1;
            char[] chars = decimalStr.toCharArray();
            for (int i = chars.length - 1; i >= 0; i--) { 
                char c = chars[i];
                sum += charValueMap.get(c) * multiple;
                multiple *= decimal;
            }
            return sum;
        }
    
    
        /** * 生成短url * @param longUrl * @return */
        protected String shortenOne(String longUrl) { 
            long myseq = sequence.incrementAndGet();
            String shortUrl = to62RadixString(myseq);
            return shortUrl;
        }
    
        private String to62RadixString(long seq) { 
            StringBuilder sBuilder = new StringBuilder();
            while (true) { 
                int remainder = (int) (seq % 62);
                sBuilder.append(DIGITS[remainder]);
                seq = seq / 62;
                if (seq == 0) { 
                    break;
                }
            }
            return sBuilder.toString();
        }
    }