package main
import (
"fmt"
"github.com/syndtr/goleveldb/leveldb"
)
func main() {
levelDB()
}
func levelDB() {
//定义字符数组key value
key := []byte("Test")
value := []byte("Test Level DB")
//定义字符串的键值对
k1 :="key"
v1 :="value"
// The returned DB instance is safe for concurrent use.
// The DB must be closed after use, by calling Close method.
//文件夹位置,获取db实例-设置数据库文件的位置
db, err := leveldb.OpenFile("path/to/db", nil)
//leveldb.
//延迟关闭db流,必须的操作
defer db.Close()
if err != nil {
fmt.Println(err)
}
//向db中插入键值对
e := db.Put(key, value, nil)
//将字符串转换为byte数组
e = db.Put([]byte(k1), []byte(v1), nil)
fmt.Println(e)//
/**
|| 注意:查看路径下的db文件,可知道文件都是自动切分为一些小文件.
*/
//根据key值查询value
data, _ := db.Get(key, nil)
fmt.Println(data)//[84 101 115 116 32 76 101 118 101 108 32 68 66]
fmt.Printf("%c\n",data)//[T e s t L e v e l D B]
data, _ = db.Get([]byte(k1), nil)
fmt.Println(data)//[118 97 108 117 101]
fmt.Printf("%c\n",data)//[v a l u e]
// It is safe to modify the contents of the arguments after Delete returns but
// not before.
//根据key进行删除操作
i := db.Delete(key, nil)
fmt.Println(i)//
data, _ = db.Get(key, nil)
fmt.Println(data)//[]
//
//获取db快照
snapshot, i := db.GetSnapshot()
fmt.Println(snapshot)//leveldb.Snapshot{22}
fmt.Println(i)//
//注意: The snapshot must be released after use, by calling Release method.
//也就是说snapshot在使用之后,必须使用它的Release方法释放!
snapshot.Release()
}
