POST请求

    ASIFormDataRequest *request = [ASIFormDataRequest requestWithURL:[NSURL URLWithString:urlStr]];
    [request setPostValue:[NSString stringWithFormat:@"%d",_forumId] forKey:@"topic.forum_id"];
    [request setPostValue:[NSString stringWithFormat:@"%d",userid] forKey:@"topic.user_org_id"];
    [request startSynchronous];
    NSString *returnStr = [request responseString];