SHANGHAI — President Barack Obama is walking a tightrope on his first trip to China, seeking to enlist help in tackling urgent global problems while weighing when and how — or if — he should raise traditional human rights concerns.

Obama arrived in Shanghai late at night, in a driving rain, hustling through a phalanx of umbrella-holding dignitaries to reach his limousine. On Monday, the president is holding talks with local politicians and, in one of the marquee events of his weeklong Asian trip, conducting an American-style town hall discussion with Chinese university students.