4、 展示对应的内容.
package util; import redis.clients.jedis.Jedis; public class ShortUrlUtil { private static final String SHORT_URL_KEY = "SHORT_URL_KEY"; private static final String LOCALHOST = "http://localhost:4444/"; private static final String SHORT_LONG_PREFIX = "short_long_prefix_"; private static final String CACHE_KEY_PREFIX = "cache_key_prefix_"; private static final int CACHE_SECONDS = 1 * 60 * 60; private final String redisConfig; private final Jedis jedis; public ShortUrlUtil(String redisConfig) { this.redisConfig = redisConfig; this.jedis = new Jedis(this.redisConfig); } public String getShortUrl(String longUrl, Decimal decimal) { // 查询缓存 String cache = jedis.get(CACHE_KEY_PREFIX + longUrl); if (cache != null) { return LOCALHOST + toOtherBaseString(Long.valueOf(cache), decimal.x); } // 自增 long num = jedis.incr(SHORT_URL_KEY); // 在数据库中保存短-长URL的映射关系,可以保存在MySQL中 jedis.set(SHORT_LONG_PREFIX + num, longUrl); // 写入缓存 jedis.setex(CACHE_KEY_PREFIX + longUrl, CACHE_SECONDS, String.valueOf(num)); return LOCALHOST + toOtherBaseString(num, decimal.x); } /** * 在进制表示中的字符集合 */ final static char[] digits = {'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', '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'}; /** * 由10进制的数字转换到其他进制 */ private String toOtherBaseString(long n, int base) { long num = 0; if (n < 0) { num = ((long) 2 * 0x7fffffff) + n + 2; } else { num = n; } char[] buf = new char[32]; int charPos = 32; while ((num / base) > 0) { buf[--charPos] = digits[(int) (num % base)]; num /= base; } buf[--charPos] = digits[(int) (num % base)]; return new String(buf, charPos, (32 - charPos)); } enum Decimal { D32(32), D64(64); int x; Decimal(int x) { this.x = x; } } public static void main(String[] args) { for (int i = 0; i < 100; i++) { System.out.println(new ShortUrlUtil("localhost").getShortUrl("www.baidudu.com", Decimal.D32)); System.out.println(new ShortUrlUtil("localhost").getShortUrl("www.baidu.com", Decimal.D64)); } } }