Nikkei gains on upbeat U.S. corporate earnings, data

* U.S. economic recovery hopes invite long-money to Japan - trader * Nikkei poised to post biggest weekly gain in 2 months * Trading thin as many markets closed for Easter By Ayai Tomisawa TOKYO, April 18 (Reuters) - Japan's Nikkei share average advanced on Friday after upbeat U.S. economic data and corporate earnings bolstered investors' risk appetite. The Nikkei was up 0.4 percent at 14,474.83 in midmorning trade after ending flat at 14,417.53 the previous day. For the wee