When President Xi Jinping of China addresses American business executives here Tuesday night, he will face a crowd that was once one of China’s biggest cheerleaders but whose enthusiasm has waned. A star-studded cast of corporate America will be listening for the fine print if, as expected, Mr. Xi tells it that China Inc. is open for business. Friction has been growing over China’s barriers to market access, rampant commercial cybertheft and the imposition of intrusive security measures on foreign technology companies.The U.S.-China Business Council, one of the hosts of the dinner event, said member confidence about doing business in China had eroded considerably over the past five years. In 2010, 58 percent of executives were optimistic about the business outlook in China, while 33 percent were somewhat optimistic, said John Frisbie, the council’s president. Now, just 24 percent of executives surveyed are optimistic about doing business there, and 67 percent are somewhat optimistic or neutral.