The battle over Atlantic Yards has already raged longer than the Civil War, with eight years of protests, petitions and lawsuits seeking to halt a project that promised to reshape the heart of Brooklyn.

Even now, as the oyster-shaped basketball arena that will anchor a 22-acre housing and office complex rises against the low-slung Brooklyn skyline, die-hard opponents are still resisting. Last week they packed a hearing held by two community boards to block the arena from speedily receiving a liquor license.

But almost six months before the Barclays Center opens its doors to the Nets, Brooklyn’s first major professional sports team since the lamented Dodgers, the reality is that the Atlantic Yards project has already done the very thing that critics feared and supporters promoted: transform surrounding neighborhoods prized for their streets of tree-lined brownstones and low-key living.

Shops along the workaday stretch of Flatbush Avenue south of the arena that for generations sold unglamorous products like hardware, paint, plumbing supplies, prescription drugs, even artificial limbs, are seeing new businesses pop up that sell high-heel shoes for $3,500 a pair, revealing party dresses, exotic cheeses and, of course, high-priced martinis. Dozens of restaurants and bars, with beguiling names like Fish and Sip and Va beh’ (Italian slang for “It’s all good!”), have sprouted on major thoroughfares and serene side streets.