json.commit_users_count @exercise_users_size #已提交用户数
json.exercise_users do
json.array! @exercise_users do |ex|
ex_user = ex.user
json.user_id ex_user.id
json.user_name ex_user.real_name
json.student_id ex_user.user_extension.student_id
json.user_score ex.score
end
