排行榜功能是一個很普遍的需求，對于這類需求如果數據總量過大用mysql實現的話會很浪費性能。

select * from rank_name order by score desc limit 0,10

這時候可以考慮使用redis中的有序集合來實現（以下是會用到的一些命令）

zrange 查看排行榜 (升序)

zrevrange 查看排行榜 （降序）

zadd 添加一個數據

zrem 刪除一個數據

zrank 獲取排名（升序）

zrevrank 獲取排名 （降序）

以下是golang代碼實現

c1,err := redis.Dial("tcp","127.0.0.1:6379")
    if err != nil {
        panic(err)
    }
    defer c1.Close()
    _, err = c1.Do("zrange","rank_name","0","-1","withscores")
    if err != nil {
        return
    }
    for i := 0; i <100; i++ {
        c1.Do("zadd","rank_name",rand.Intn(1000),"張"+strconv.Itoa(i))
    }
    do, err := redis.ByteSlices(c1.Do("zrange", "rank_name", 0, -1,"withscores"))
    if err != nil {
        return
    }
    for _, v := range do {
        fmt.Println(string(v))
    }

以下是運行結果，可以看到數據已經按照score排序了

其他例子，普通方式：使用參數

這種方式(method(conn, …))需要將其寫在參數中，比較繁瑣，也不便于找到其相關的方法，于是我們對其進行了結構體封裝，請略過以下代碼！

package main


import (
    "fmt"
    "github.com/garyburd/redigo/redis"
)


func main() {
    conn := redisConnect()
    defer conn.Close()


    setString(conn, "country", "China")
    getString(conn, "country")


}


// connect redis
func redisConnect() redis.Conn {
    conn, err := redis.Dial("tcp", "127.0.0.1:6379")
    if err != nil {
        fmt.Println("connect redis error:", err)
        return nil
    }
    fmt.Println("connect redis success!")


    return conn
}


// setString SET filed value
func setString(conn redis.Conn, field string, value interface{}) {
    _, _ = conn.Do("SET", field, value)
}


// getString GET field
func getString(conn redis.Conn, field string) {
    res, _ := redis.String(conn.Do("GET", field))
    fmt.Printf("Get %s: %s 
", field, res)
}

使用結構體封裝進行方法調用

使用這種方式(db.method(…))進行封裝，不僅便于書寫，而且也更容易找到相關的方法來調用

package main


import (
    "fmt"
    "github.com/garyburd/redigo/redis"
    "log"
    "reflect"
)


func main() {
    conn := RedisConnect()
    defer conn.Close()


    // 認證信息
    // if _, err := conn.Do("username", "password"); err != nil {
    //  conn.Close()
    // }


    db := Conn{conn}


    // 刪：key鍵
    // db.DelKey("score")
    // 刪：單條數據
    // db.DelSortSetByField("score", "Tom")


    // 增
    db.SetSortSet("score", 96, "Coulson")
    db.SetSortSet("score", 92, "Tom")
    db.SetSortSet("score", 97, "Jack")
    // 查：長度
    fmt.Println(db.GetSortSetLength("score"))
    // 查：排名(asc: 升序, desc: 降序, int: 降序前n條數據)
    nameRank, scoreRank := db.RankSortSet("score", "asc")
    fmt.Println(nameRank, scoreRank)
    // 查：單條數據
    fmt.Println(db.GetSortSetByField("score", "Tom"))


}


// RedisConnect connect redis
func RedisConnect() redis.Conn {
    conn, err := redis.Dial("tcp", "127.0.0.1:6379")
    if err != nil {
        fmt.Println("connect redis error:", err)
        return nil
    }
    fmt.Println("connect redis success!")


    return conn
}


type Conn struct {
    redis.Conn
}


func (conn *Conn) DelKey(key string) {
    _, err := conn.Do("DEL", key)
    if err != nil {
        log.Printf("Failed to del the key: %s 
", key)
    }
    fmt.Printf("success to del the key: %s! 
", key)
}


// SetSortSet ZADD key ...
func (conn *Conn) SetSortSet(key string, value int, field string) {
    _, err := conn.Do("ZADD", key, value, field)
    if err != nil {
        // error: WRONGTYPE Operation against a key holding the wrong kind of value
        log.Printf("Already exist duplicate keys: `%s` 
", key)
        panic(err)
    }
    log.Printf("success to set key: %s %d %s", key, value, field)
}


// GetSortSetLength ZCARD key
func (conn *Conn) GetSortSetLength(key string) interface{} {
    res, err := conn.Do("ZCARD", key)
    if err != nil {
        panic(err)
    }
    return res
}


// RankSortSet sort
func (conn *Conn) RankSortSet(key string, limit interface{}) (nameArr []string, valueArr []string) {
    // ZRANGE score 0 -1 WITHSCORES        # 遞增排列
    // ZRANGE salary 0  WITHSCORES      # [0, n)
    // fmt.Println(reflect.TypeOf(limit).Name())
    cmd, index := "ZREVRANGE", -1
    switch {
    case limit == "asc":
        cmd = "ZRANGE"
        index = -1
    case limit == "desc":
        cmd = "ZREVRANGE"
        index = -1
    case reflect.TypeOf(limit).Name() == "int" && int(reflect.ValueOf(limit).Int()) > 0:
        index = int(reflect.ValueOf(limit).Int()) - 1
    default:
        cmd = "ZREVRANGE"
        index = -1
    }
    // scoreMap, err := redis.StringMap(conn.Do("ZRANGE", "score", 0, -1, "withscores"))
    scoreMap, err := redis.StringMap(conn.Do(cmd, "score", 0, index, "withscores"))
    if err != nil {
        log.Printf("Failed to rank by key %s 
", key)
    }
    // sort
    for name := range scoreMap {
        nameArr = append(nameArr, name)
        valueArr = append(valueArr, scoreMap[name])
    }
    return nameArr, valueArr
}


// GetSortSetByField 獲取單個數據
func (conn *Conn) GetSortSetByField(field string, value interface{}) interface{} {
    res, err := redis.Int(conn.Do("ZSCORE", field, value))
    if err != nil {
        log.Printf("can't find %v of %v 
", field, value)
    }
    return res
}


// DelSortSetByField 刪除單條數據
func (conn *Conn) DelSortSetByField(field string, value interface{}) interface{} {
    res, err := conn.Do("ZREM", field, value)
    if err != nil {
        log.Printf("failed to del %v by %v 
", field, value)
    }
    return res
}