Is there something like ASP.NET web user controls in Java/struts/jsp

Question

In java/struts/jsp world, is there something like the ASP.NET custom user control, a piece of UI with back end code that performs a specific logic, and can be pulled and used in another place (for example something like the login control).

Answer 1

The current Java EE API offers JSF 2.0 on Facelets for this. Note that Struts(2) is actually a competitor to JSF and that JSP is a view technology like ASP, not a MVC framework. As per Java EE 6 / JSF 2.0, JSP is been replaced by Facelets as the default view technology.

On top of the basic JSF implementation you can choose from a lot of "rich" component libraries which adds an extra CSS and Ajax sausage, for example PrimeFaces (showcase) and OpenFaces (showcase).

See also:

• What is the mainstream Java alternative to ASP.NET?
• What is the difference between JSP, Servlet and JSF?
• Java EE 6 tutorial - chapters 4-10
• Coreservlets.com JSF 2.0 tutorial

Answer 2

What you are after is called tag files in JSP. I found that they are not as easy to learn and use as .NET user controls.

You can use them similarly to user controls .NET.

workflow is like this.

1. Create a tag file in web-inf/tags/AtillaTagLibrary/DropDownList.tag

2. reference your tag file in your jsp file like below

   <%@ taglib prefix="ct" tagdir="/WEB-INF/tags/AtillaTagLibrary"%>
   

3. Use your tag file like normal jsp tag.

   <ct:DropDownList  />
   

This tag files can get attribute values from outside like user controls.