Is it possible to save state of Web application

I build a Web application using GWT (and/or SmartGWT) that uses a number of forms to collect data. Is 开发者_开发知识库it possible to save the progress so that the user can leave the application and when comes back continues with the data (s)he has already entered?

If yes, do I have to use a database?

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Of course.

One of the way is use the GWT 's RPC framework to make calls to Java servlets . You do not need a database to store the form data as you can store the form data inside the HttpSession object provided by the Java servlets . You can imagine HttpSession has a built-in data store that allows you to store any number of key/value pairs and each client has their own HttpSession.

You can refer to the followings links/ tutorials to get the basic ideas .

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References

• Using Servlet Sessions in GWT – Tutorial
• Google Web Toolkit (GWT) & Servlets - Web application tutorial
• Google official document - Communicate with a Server

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Another way is to store the data in the browser. This way you won't need a server-side database.

You can either use browser cookies (note that cookies expire...):
http://google-web-toolkit.googlecode.com/svn/javadoc/2.3/com/google/gwt/user/client/Cookies.html

Or the all new GWT HTML5 storage API:
http://code.google.com/webtoolkit/doc/latest/DevGuideHtml5Storage.html
http://google-web-toolkit.googlecode.com/svn/javadoc/2.3/com/google/gwt/storage/client/Storage.html