private String login(String[] msgArr) {
		String ans=null;
		user.User user = forumSystem.login(msgArr[1], msgArr[2], msgArr[3]);
		if(user!=null){
			ans="SUCC_"+user.getUsername();
			this.user=user;
		}
		else ans="ERR_LOGIN";
						
					
	return ans;
	}