UMem Redis - Surfercloud

Counting, Generating Unique IDs

All Redis commands are atomic, you can easily use INCR, DECR commands to build a counter system. Similarly, you can use the INCR command to generate unique IDs for game players.

Example:


import java.util.Scanner;
import redis.clients.jedis.Jedis;
public class Incr {
    // Count once for each web access
    public static void accessWeb(Jedis jedis, String url) {
        jedis.incr(url);
    }
    public static void main(String[] args) {
        String host = "127.0.0.1";
        int port = 10011;
        Jedis jedis = new Jedis(host, port);
        String url = "console.surfercloud.com";
        //Get the original value
        long origin_cnt = Long.parseLong(jedis.get(url));
        //Receive terminal input
        Scanner sc = new Scanner(System.in);
        while(true) {
            System.out.println("Access " + url +" ? [y/n]");
            String ac = sc.nextLine();
            if (ac.equals("y")) {
            accessWeb(jedis,url);
            }else {
                break;
            }
        }
        sc.close();
        //Get the current value
        long now_cnt = Long.parseLong(jedis.get(url));
        //Calculate the number of visits to console.surfercloud.com.
        System.out.println("You have visited "+ url+ " " + Long.toString(now_cnt - ori
        gin_cnt)+" times.");
        jedis.close();
    }
}

Output


Access console.surfercloud.com ? [y/n]
y
Access console.surfercloud.com ? [y/n]
y
Access console.surfercloud.com ? [y/n]
y
Access console.surfercloud.com ? [y/n]
y
Access console.surfercloud.com ? [y/n]
n
You have visited console.surfercloud.com 4 times.