Judge McDonald said the shop owner thought Hemara had a firearm and handed over $290 from the till. Hemara then ran to a getaway car on Kaka St.
It was the second armed robbery of the dairy in less than two years and its owner said the crimes had a major emotional impact on his family.
In a victim-impact statement submitted to the court, he said he feared Hemara would shoot him and still felt scared when people entered his shop.
Commenting on the sentence, the shopkeeper said: "He [Hemara] has already spent two to three months in custody, which will be taken into account, so the actual time he'll spend in jail would be less than three years. The sentence for such offending should be higher, otherwise people will come out of prison and do the same thing again."
In court, lawyer Lucy Postlewaight said Hemara had written a letter of apology and attended courses while on remand.
The judge said Hemara's disguise showed his planning and preparation had been sophisticated.
The shoplifting charges related to thefts from three retailers.
-During the first robbery, in June 2012, one of three robbers held a machete to the couple in front of their son, 9.