Ashley Tisdale -- VICTORY IN STALKER CASE ... Restraining Order Granted

Ashley Tisdale appeared in an L.A. courtroom Wednesday to personally beg the court for a permanent restraining order against her alleged stalker ... and the judge has granted her wish.

Nicholas Fiore has been ordered to stay at least 100 yards away from Tisdale and her boyfriend for the next THREE YEARS ... after allegedly threatening the "High School Musical" star -- and bombarding her with more than 18,000 tweets.

Tisdale told the judge she does not know Fiore personally ... and does not consider him a friend ... but said, "I know that he's been tweeting me and has come to my house several times."

Tisdale says Fiore recently violated the temporary restraining order that was already in place by sending her tweets ... when he had been ordered to restrain from all contact, including Twitter.

Fiore did not appear in court -- he's currently being held at L.A. Men's Central Jail ... where he's been in custody since he was arrested for felony stalking.

As part of the restraining order, Fiore is not allowed to possess a firearm -- and the judge ruled that if Fiore currently owns a gun, he must surrender it within 24 hours of his release from jail.