1、安装leveldb驱动，下载地址 https://github.com/google/leveldb
    2、将leveldb.lua存放到openresty的lualib/resty/下
    3、在leveldb.lua中leveldb_so指定libleveldb.so地址
    4、运行luajit demo.lua

    local leveldb = require "resty.qc.leveldb"
    local db = leveldb:new("/tmp/test_leveldb")

    local keys = {"001","k1","k2"}
    --db:batchDel(keys)
    db:batchSet({k1="0000000000000001",k2="00000000000000012"})

    db:set("001","one")
    --print(db:get("001"))
    --print(db:get("k1"))

    db:iterator_new()
    --db:iterator_seek("001")
    --print(db:iterator_next())

    for v in db:iterator_next() do
        print(v)
    end
    db:close()

    1、db:get(key)
    2、db:set(key,val) / db:batchSet(table)
    3、db:del(key) / db:batchDel(table)
    4、db:iterator_new/iterator_seek/iterator_next/iterator_first/iterator_last
    5、db:close()

存储kv
curl "http://127.0.0.1/?k=0001&v=Falcon.C"

获取key
curl "http://127.0.0.1/?k=0001"