This is similar to a previously asked question and you may find some additional information there.

http://www.reddit.com/r/AskHistorians/comments/1qura8/how_were_japanese_prisoners_of_war_treated_by/

You're going to have to google this topic up. There is a LOT of results and discussions regarding American treatment of Japanese POWs.

To make it short: We treated the Japanese well in accordance to the Geneva Convention.

The Americans at first in the entry into the Pacific War after Pearl Harbor hated the Japanese a LOT. The only reason why we didn't take them prisoners easily because the way they acted towards us. During the Battle of Guadalcanal, U.S. Marine officer Frank Goettge and his patrol saw a white flag far away in the creek. Unknown to them, the white flag was obscured by an Imperial Japanese Red Circle which was covered by bush. Furthermore, the Japanese prisoner told the Americans that the ones who raised the white flag wanted to surrender and demanded that the Americans should go over there and take them prisoner. Unfortunately when the patrol DID come over to accept their surrender, they were ambushed by Japanese troops and wiped out.

That was one of the many reasons why the Americans developed a "take no prisoner" attitude because of this treacherous ruse. Further treachery and trickery by Japanese troops throughout the Pacific War furthered this attitude harder than ever.

That said, we did try to treat them well in accordance to the Geneva Convention because even though our war crimes against enemy POWs were not in a big scale as the Germans, Japanese, and the Russians in WWII, doing so would make our enemies treat our POWs even more worse than they had ever been.