Frame work problem along with tag libraries...

Question

Hi..
I am new to jsp and am making a project in it, I am following MVC architecture but my problem is i am unable to understand all this concept of frameworks like struts, spring etc... i need some help with what they actually are..??
also i am not using any tag libraries in my project i am using simple jsp files with minimum java coding at the front end and class files at the logic layer... and then the databse layer... i want to know is it better to use tag libraries and for using them will i have to follow any particular framework.. and are these tag libraries different for different frameworks..??... will i be missing something if i don't use tag libraires or don't follow a particular framework...???

Answer 1

Those taglibs are particularly for the view layer of the MVC pattern. In a MCV framework you use taglibs to associate beans from the model/controller layer with the view layer. The framework will care about getting and setting the bean properties during the HTTP request-response cycle. With for example Sun JSF framework the relevant part of your JSP page would look like:
<h:form>
    <h:inputText value="#{myBean.input}" />
    <h:commandButton value="submit" action="#{myBean.submit}" />
</h:form>The JSF framework will generate this as something like<form name="someGeneratedName" method="post" action="currentPage.jsf">
    <input type="text" id="someGeneratedId" name="someGeneratedName" value="theInputValueFromMyBeanIfAny" />
    <input type="submit" id="someGeneratedId" name="someGeneratedId" value="submit" />
</form>The MyBean class would look like something as:public class MyBean {
    private String input;
    public void submit() {
        System.out.println("The framework has already set the input value: " + input);
        // You can do with this whatever you want. Eg persisting in DB:
        DAOFactory.getInstance("dbname").getSomeDAO().save(new SomeDTO(input));
    public String getInput() {
        return input;
    public void setInput(String input) {
        this.input = input;
}The average MVC framework also provides customizable Converters (convert between String for output and the desired Object type in model/controller layer) and Validators (required values, numeric values, date values, etc). Each MVC framework have its own taglibraries. For example JSF with the URI's http://java.sun.com/jsf/core and /html. Struts has another taglibs. Further on there is also the Java Standard Tag Library (JSTL) with the URI's http://java.sun.com/jsp/jstl/core, /functions and so on. Mixing of the taglibs is possible, but not always recommended. You should prefer the taglib of the framework used, but if the framework doesn't provide the tag with the desired functionality, then you can add another taglib, such as JSTL or, in case of JSF, Apache Tomahawk and JBoss Ajax4jsf.
If you want to learn more about JSF, you may find this article useful: [http://balusc.blogspot.com/2008/01/jsf-tutorial-with-eclipse-and-tomcat.html].