Atticus is unhappy at the outcome of the trial, but not surprised, as he knew from the start his fight to prove Tom Robinson's innocence was doomed. He fought the good fight because he knew it was the right thing to do, not because he thought the systemic racism of the whites in Maycomb would suddenly turn around and change into racial justice.
Jem and Scout take it harder. As children, they were innocent enough to hope that the jury might declare Tom Robinson not guilty. They sat through the trial and knew that Atticus had proven that Robinson, with his withered arm, could not have raped Mayella as she described. They have, therefore, to deal with the disillusionment of knowing their fellow townspeople realized the truth and refused to act on it, preferring to uphold a racist system instead. Jem takes it very hard, and Scout, though quieter about it, has much to absorb, growing outraged that her teacher could support the Robinson conviction and at same time condemn the Germans for their treatment of the Jews.
The townspeople have different opinions about the trial, but the consensus of the people of Maycomb appears to be typified by the ladies of the Missionary Society who Aunt Alexandra entertains. They are glad the trial is over and had the outcome it did. They are angry at their servants for getting uppity about it and feel a need to put them in their places. However, some townspeople, like Mr. Underwood, the newspaper editor, and Miss Maudie, wish justice had been served.