Showing Days of Infamy by Harry Turtledove

Japanese Zeros appear in the skies over Hawaii and descend upon Pearl Harbor in a devastating attack that cripples the U.S. Navy fleet and airfields. One after another the islands are conquered and occupied by the Empire of the Sun. In the hands of a merciless enemy American soldiers in POW camps suffer cruel punishment. Many older Hawaiians of Japanese origin support the invaders - while some of their children want to fight back.
But the domination of the Pacific and the submission of those who live there is merely the beginning. With the U.S. military on Hawaii completely subjugated there is no one to stop the Japanese from using the islands' resources to launch an offensive against America's western coast...