golang leveldb获取快照错误

Question

I am get leveldb's all key-val to a map[string][]byte, but it is not running as my expection. code is as below

package main
import (
    "fmt"
    "strconv"
    "github.com/syndtr/goleveldb/leveldb"
)
func main() {
    db, err := leveldb.OpenFile("db", nil)
    if err != nil {
        panic(err)
    }
    defer db.Close()
    for i := 0; i < 10; i++ {
        err := db.Put([]byte("key"+strconv.Itoa(i)), []byte("value"+strconv.Itoa(i)), nil)
        if err != nil {
            panic(err)
        }
    }
    snap, err := db.GetSnapshot()
    if err != nil {
        panic(err)
    }
    if snap == nil {
        panic("snap shot is nil")
    }
    data := make(map[string][]byte)
    iter := snap.NewIterator(nil, nil)
    for iter.Next() {
        Key := iter.Key()
        Value := iter.Value()
        data[string(Key)] = Value
    }
    iter.Release()
    if iter.Error() != nil {
        panic(iter.Error())
    }
    for k, v := range data {
        fmt.Println(string(k) + ":" + string(v))
    }
}

but the result is below key3:value9 key6:value9 key7:value9 key8:value9 key1:value9 key2:value9 key4:value9 key5:value9 key9:value9 key0:value9 rather not key0:value0

Answer 1

Problem is with casting around types (byte[] to string, etc.).

You are trying to print string values. To avoid unnecessary casting apply the following modifications:

• Change data initialization into data := make(map[string]string)
• Assign values into data with `data[string(Key)] = string(Value) (by the way, don't use capitalization for variables you aren't intend to export)
• Print data's values with fmt.Println(k + ":" + v))

This should produce the following result:

key0:value0
key1:value1
key7:value7
key2:value2
key3:value3
key4:value4
key5:value5
key6:value6
key8:value8
key9:value9