go mongodb Iter迭代器示例

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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
}