I duplicated this recipe from a wonderful little tapas restaurant in Boston that serves the best white sangria I've ever had. I asked the bartender how it was made, and here's my modified version based on what she told me. I think it tastes exactly the same. It is important to buy an unsweetened can of pineapples, as that changes the flavor drastically. Read the ingredients and make sure there's nothing besides "pineapples, and pineapple juice."
Note: Does not require 15 oz can of pineapples. They made me specify a size, just buy the smaller one.
For an extra little touch, I froze raspberries inside mango-juice ice cubes. It tastes great as it melts. Garnish with orange or kiwi slices.