For a form field, if users input " or ', we will have trouble when storing them into database. What is the standard way to solve this cases? for me, this only solution I can think of is to read every field's input , if it have ' or " character, it will be replaced by \' or \" , isn't it? I wonder if we have better way dealing with that.
" doesn't have any problem if you store in database. The only problem is with single quote '. If you are preparing a SQL query with the form submission values you need to escape the single quote by adding another single quote. If you have option of PreparedStatement you need not worry about escaping these quotes. PreparedStatement will automatically takes care of special characters. For escaping the single quotes the bestway is to write small function and append another single quote.
Even easier if you use a PreparedStatement to insert the data rather than a Statement - you don't have to do anything at all. The PreparedStatement will manage escaping special characters for you. Dave