Redis实战 第一章 代码 java

https://github.com/josiahcarlson/redis-in-action/blob/master/java/src/main/java/Chapter01.java

package chap01;

import redis.clients.jedis.Jedis;
import redis.clients.jedis.ZParams;

import java.util.*;

public class Chapter01 {
    public static final int ONE_WEEK_IN_SECONDS = 7 * 86400;
    public static final int VOTE_SCORE = 432;
    public static final int ARTICLES_PER_PAGE = 25;


    public void run() {
        Jedis conn = new Jedis("localhost");

        //使用默认数据库
        conn.select(0);


        String articleId=postArticle(conn,"username","A title",
                "http://www.google.com");

        System.out.println("We posted a new article with id: "+articleId);

        System.out.println("Its HASH looks like:");
        Map<String, String> articleData = conn.hgetAll("article:" + articleId);
        for (Map.Entry<String, String> entry : articleData.entrySet()) {
            System.out.println("   "+entry.getKey()+": "+entry.getValue());
        }
        System.out.println();

        articleVote(conn,"other_user","article:"+articleId);
        String votes=conn.hget("article:"+articleId,"votes");
        System.out.println("We voted for the article, it now has votes: "+votes);
        assert Integer.parseInt(votes)>1;

        System.out.println("The currently highest-scoring articles are:");
        List<Map<String, String>> articles = getArticles(conn, 1);
        printArticles(articles);
        assert articles.size()>=1;

        addGroups(conn,articleId,new String[]{"new-group"});
        System.out.println("We added the article to a new group, other articles include:");
        getGroupArticles(conn,"new-group",1);
        printArticles(articles);
        assert articles.size()>=1;

    }

    public void articleVote(Jedis conn, String user, String article) {
        //计算文章截止时间
        long cutoff = (System.currentTimeMillis() / 1000) - ONE_WEEK_IN_SECONDS;
        //使用zscore命令判断文章发布时间是否未超过一周
        if (conn.zscore("time:", article) < cutoff) {
            return;
        }
        //从article:id标识符里取出文章的ID
        String articleId = article.substring(article.indexOf(':') + 1);

        //如果用户是第一次投票
        if (conn.sadd("voted:" + articleId, user) == 1) {
            conn.zincrby("score:", VOTE_SCORE, article);
            conn.hincrBy(article, "votes", 1);
        }
    }

    public String postArticle(Jedis conn, String user, String title, String link) {
        String articleId = String.valueOf(conn.incr("article:"));

        String voted = "voted:" + articleId;
        conn.sadd(voted, user);
        conn.expire(voted, ONE_WEEK_IN_SECONDS);
        long now = System.currentTimeMillis() / 1000;
        String article = "article:" + articleId;
        HashMap<String, String> articleData = new HashMap<String, String>();
        articleData.put("title", title);
        articleData.put("link", link);
        articleData.put("user", user);
        articleData.put("now", String.valueOf(now));
        articleData.put("votes", "1");
        conn.hmset(article, articleData);
        conn.zadd("score:", now + VOTE_SCORE, article);
        conn.zadd("time:", now, article);
        return articleId;
    }

    public List<Map<String, String>> getArticles(Jedis conn, int page) {
        return getArticles(conn, page, "score:");
    }

    public List<Map<String, String>> getArticles(Jedis conn, int page, String order) {
        int start = (page - 1) * ARTICLES_PER_PAGE;
        int end = start + ARTICLES_PER_PAGE - 1;

        Set<String> ids = conn.zrevrange(order, start, end);

        List<Map<String, String>> articles=new ArrayList<Map<String, String>>();
        for (String id : ids) {
            Map<String,String> articleData=conn.hgetAll(id);
            articleData.put("id",id);
            articles.add(articleData);
        }
        return articles;
    }

    public void addGroups(Jedis conn,String articleId, String[] toAdd){
        String article="article:"+articleId;
        for (String group : toAdd) {
            conn.sadd("group:"+group,article);
        }
    }

    public void removeGroups(Jedis conn,String articleId, String[] toRemove){
        String article="article:"+articleId;
        for (String group : toRemove) {
            conn.srem("group:"+group,article);
        }
    }

    public List<Map<String,String>> getGroupArticles(Jedis conn,String group,int page){
        return getGroupArticles(conn,group,page,"score:");
    }

    public List<Map<String,String>> getGroupArticles(Jedis conn, String group,int page,String order){
        String key=order+group;
        if(!conn.exists(key)){
            ZParams params=new ZParams().aggregate(ZParams.Aggregate.MAX);
            conn.zinterstore(key,params,"group:"+group,order);
            conn.expire(key,60);
        }
        return getArticles(conn,page,key);
    }

    private void printArticles(List<Map<String,String>> articles){
        for (Map<String, String> article : articles) {
            System.out.println("  id: "+article.get("id"));
            for (Map.Entry<String, String> entry : article.entrySet()) {
                if(entry.getKey().equals("id")){
                    continue;
                }
                System.out.println("   "+entry.getKey()+": "+entry.getValue());
            }
        }
    }

    public static void main(String[] args) {
        new Chapter01().run();
    }

}