go mongodb Iter迭代器示例

func (this *Mongodb) StoreRecords(dbName, collection, storeDbName, tmpCollection string, queryMap, selecter bson.M) (err error) {	session := this.GetSession()	defer session.Close()	iter := session.DB(dbName).C(collection).Find(queryMap).Select(selecter).Iter()	oneMap := make(bson.M)	historyMapSlice := make([]interface{}, 0, MAX_BULK_WRITE_FILE_LEN)	flag := false	for iter.Next(&oneMap) {		tmpMap := DeepCopy(oneMap)//go深度拷贝		historyMapSlice = append(historyMapSlice, tmpMap.(bson.M))		if len(historyMapSlice) >= MAX_BULK_WRITE_FILE_LEN {//写入最大长度			this.BulkInsert(storeDbName, tmpCollection, historyMapSlice)			historyMapSlice = make([]interface{}, 0, MAX_BULK_WRITE_FILE_LEN)			flag = true		}	}	if err = iter.Close(); err != nil {		log.Error("StoreRecords,iter.Close() fail, db:", dbName,			", Collection:", collection,			", queryCondition:", queryMap,			", selector:", selecter,			", ErrInfo:", err)	}	if 0 == len(historyMapSlice) && !flag {		err = errors.New("not found StoreRecords data")		return	}	this.BulkInsert(storeDbName, tmpCollection, historyMapSlice)	return}
func (this *Mongodb) BulkInsert(dataBase, collection string, allRecords []interface{}) (err error) {    if 0 == len(allRecords) {        log.Info("bulkInsert: 0 == len(allRecords)! db:", dataBase, "collection:", collection)        return    }    bulkInsert := func(c *mgo.Collection) error {        bulk := c.Bulk()        bulk.Unordered()        bulk.Insert(allRecords...)        _, err := bulk.Run()        return err    }    err = this.WitchCollection(dataBase, collection, bulkInsert)    if err != nil {        log.Error("mongodb BulkInsert, BulkInsert Failed, db:", dataBase,            ", Collection:", collection,            ", ErrInfo:", err)    }    return}