Pdf of struts 2

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Data Structures. Operating System. Note the file name is struts. This minimal Struts 2 configuration file tells the framework that if the URL ends in index. For more information about the struts. Run mvn jetty:run to run the web-application using the jetty maven-plugin. View the console where you should see numerous debug messages that tell you the Struts 2 framework is being included in the basic-struts2 web application.

View the log messages written to the console and you should find several that discuss index. Also, Struts2 has recognised the takeover by Web2. Moreover, integration with other frameworks like Spring, Tiles and SiteMesh is now easier with a variety of integration available with Struts2. Tag markups in Struts2 can be tweaked using Freemarker templates. This does not require JSP or java knowledge.

Thus, web applications can be easily designed using Struts 2 in a robust way. Struts 2 is slightly different from a traditional MVC framework in that the action takes the role of the model rather than the controller, although there is some overlap. The fig. The controller is implemented with a Struts2 dispatch servlet filter as well as interceptors, the model is implemented with actions, and the view as a combination of result types and results. The value stack and OGNL provide common thread, linking and enabling integration between the other components.

The fig 2 describes the Struts 2 request lifecycle. Figure 2. Struts2 request lifecycle Based on the above diagram, user's request life cycle in Struts 2 as follows: 1. Firstly the user sends a request to the server for requesting for some resource ex. A web page through the browser. The FilterDispatcher looks at the request and then determines the appropriate Action.

Configured interceptors functionalities are applied such as validation, file upload etc. Selected action is executed to perform the requested operation. The next annotation is the Action annotation. This is used to decorate the execute method. The Action method also takes in a value which is the URL on which the action is invoked.

Finally, I have used two validation annotations. I have configured the required field validator on name field and the integer range validator on the age field. I have also specified a custom message for the validations. We really do not need struts. Struts 2 applications can use Java 5 annotations as an alternative to XML and Java properties configuration. This iterator will iterate over a value. An iterable value can be either itherjava. Collection or java. Iterator file.

While iterating over an iterator, you can use Sort tag to sort the result or SubSet tag to get a sub set of the list or array. The following example retrieves the value of the getDays method of the current object on the value stack and uses it to iterate over. These generator tag generates an iterator based on the val attribute supplied. The following generator tag generates an iterator and prints it out using the iterator tag. The Struts 2 data tags are primarily used to manipulate the data displayed on a page.

This tag enables developers to call actions directly from a JSP page by specifying the action name and an optional namespace. The body content of the tag is used to render the results from the Action. Any result processor defined for this action in struts. These bean tag instantiates a class that conforms to the JavaBeans specification. This tag has a body which can contain a number of Param elements to set any mutator methods on that class.

If the var attribute is set on the BeanTag, it will place the instantiated bean into the stack's Context. These date tag will allow you to format a Date in a quick and easy way. You can specify a custom format eg. These param tag can be used to parameterize other tags. This tag has the following two parameters. These property tag is used to get the property of a value, which will default to the top of the stack if none is specified. These set tag assigns a value to a variable in a specified scope.

It is useful when you wish to assign a variable to a complex expression and then simply reference that variable each time rather than the complex expression.

The scopes available are application, session, request, page and action. The list of form tags is a subset of Struts UI Tags. These tags help in the rendering of the user interface required for the Struts web applications and can be categorised into three categories. We have used these tags in our examples already, we will brush them in this chapter.

Let us look a simple view page email. When we execute the above program, we get the following user interface provided you have setup proper mapping for all the keys used. As shown, the s:head generates the javascript and stylesheet elements required for the Struts2 application. Next, we have the s:div and s:text elements. For those people, they have the choice to use s:div to render a div. Next we have the famiilar s:form tag.

The s:form tag has an action attribute that determines where to submit the form. Because we have a file upload element in the form, we have to set the enctype to multipart. Otherwise, we can leave this blank. At the end of the form tag, we have the s:submit tag. This is used to submit the form. When the form is submitted, all the form values are submitted to the the action specified in the s:form tag.

Inside the s:form, we have a hidden attribute called secret. This renders a hidden element in the HTML. In our case, the "secret" element has the value "abracadabra".

This element is not visible to the end user and is used to carry the state from one view to another. Next we have the s:label, s:textfield, s:password and s:textarea tags. These are used to render the label, input field, password and the text area respectively.

We have seen these in action in the "Struts - Sending Email" example. The important thing to note here is the use of "key" attribute. The "key" attribute is used to fetch the label for these controls from the property file.

We have already covered this feature in the Struts2 Localization, internationalization chapter. Then, we have the s:file tag which renders a input file upload component. This component allows the user to upload files. In this example, we have used the "accept" parameter of the s:file tag to specify which file types are allowed to be uploaded. Finally we have the s:token tag.

The token tag generates an unique token which is used to find out whether a form has been double submitted. When the form is rendered, a hidden variable is placed as the token value. Let us say, for example that the token is "ABC". When this form is submitted, the Struts Fitler checks the token against the token stored in the session. If it matches, it removes the token from the session. Now, if the form is accidentally resubmitted either by refreshing or by hitting the browser back button , the form will be resubmitted with "ABC" as the token.

In this case, the filter checks the token against the token stored in the session again. But because the token "ABC" has been removed from the session, it will not match and the Struts filter will reject the request.

The group UI tags are used to create radio button and the checkbox. Let us look a simple view page HelloWorld. Let us look at the example now. In the first example, we are creating a simple radio button with the label "Gender".

The name attribute is mandatory for the radio button tag, so we specify a name which is "gender". We then supply a list to the gender. The list is populated with the values "male" and "female". Therefore, in the output we get a radio button with two values in it.

In the second example, we are creating a checkbox list. This is to gather the user's hobbies. The user can have more than one hobby and therefore we are using the checkbox instead of the radiobutton. The checkbox is populated with the list "sports", "TV" and "Shopping". This presents the hobbies as a checkbox list. Let us explore the different variations of the Select Tag offered by Struts. First, the select tag renders the HTML select box. In the first example, we are creating a simple select box with name "username" and the label "username".

The select box will be populated with a list that contains the names Mike, John and Smith. In the second example, our company has head offices in America. It also has global offices in Asia and Europe. We want to display the offices in a select box but we want to group the global offices by the name of the continent. This is where the optgroup comes in handy.

We use the s:optgroup tag to create a new group. We give the group a label and a separate list. In the third example, the combobox is used. A combo box is a combination of an input field and a select box. The user can either select a value from the select box in which case the input field is automatically filled in with the value the user has selected. Should the user to enter a value directly, no values from the select box will be selected.

In our example we have the combobox listing the sun signs. The selectbox lists only four entries allowing the user to type in his sun sign if it is not in the list. We also add a header entry to the select box. The headerentry is the one that is displayed at the top of the select box.

In our case we want to display "Please Select". If the user does not select anything, then we assume -1 as the value. In some cases, we do not want the user to select an empty value. In those conditions, one would set the "emptyOption" property to false. Finally, in our example we supply "capricorn" as the default value for the combobox.

In the fourth example, we have a double select. A double select is used when you want to display two select boxes. The value selected in the first select box determines what appears in the second select box.

In our example the first select box displays "Technical" and "Other". If the user selects Technical, we will display IT and Hardware in the second select box. Otherwise we will display Accounting and HR. This is possible using the "list" and "doubleList" atrributes as shown in the example. In the above example, we did a comparison to see if the top select box equals Technical. If it does, then we display IT and Hardware. First of all, to proceed with this example, you need to add struts2-dojo-plugin First thing to notice is the addition of a new tag library with the prefix sx.

This struts-dojo-tags is the tag library specifically created for the ajax integration. Then inside the HTML head we call the sx:head. This initializes the dojo framework and makes it ready for all AJAX invocations within the page.

This step is important - your ajax calls will not work without the sx:head being initialized. First we have the autocompleter tag. The autocompleter tag looks pretty much like a select box. It is populated with the values red, green and blue. But the different between a select box and this one is that it auto completes.

That is, if you start typing in gr, it will fill it with "green". Other than that this tag is very much similar to the s:select tag which we covered earlier. Next, we have a date time picker.

This tag creates an input field with a button next to it. When the button is pressed, a popup date time picker is displayed. When the user selects a date, the date is filled into the input text in the format that is specified in the tag attribute. Next we create a url tag to the system. It doesn't have to be the system. Then we have a div with the hyperlink set to the url and delay set to 2 seconds. What happens when you run this is, the "Initial Content" will be displayed for 2 seconds, then the div's content will be replaced with the contents from the hello.

Finally we have a simple tab panel with two tabs. The tabs are divs themseleves with the labels Tab 1 and Tab2. It should be worth noting that the AJAX tag integration in Struts is still a work in progress and the maturity of this integration is slowly increasing with every release.

Spring is a popular web framework that provides easy integration with lots of common web tasks. So the question is, why do we need Spring when we have Struts2? Well, Spring is more than a MVC framework - it offers many other goodies which are not available in Struts. For example: dependency injection that can be useful to any framework.

In this chapter, we will go through a simple example to see how to integrate Spring and Struts2 together. First of all, you need to add the following files to the project's build path from Spring installation. Finally add struts2-spring-plugin-x. If you are using Eclipse then you may face an exception java. ClassNotFoundException: org. Finally make sure there is no dependency conflict available under the marker tab.

The important thing to note here is the listener that we have configured. The ContextLoaderListener is required to load the spring context file. Spring's configuration file is called applicationContext. Let us create a simple action class called User. Now let us create the applicationContext. As seen above, we have configured the user bean and we have injected the values Michael and Jackson into the bean.

We have also given this bean a name "userClass", so that we can reuse this elsewhere. Next let us create the User. The User. It serves only one purpose - to display the values of the firstname and lastname of the user object. Finally, let us put all entities together using the struts. The important thing to note is that we are using the id userClass to refer to the class. This means that we are using spring to do the dependency injection for the User class. We have now seen how to bring two great frameworks together.

This concludes the Struts - Spring integration chapter. In this chapter, let us go through the steps involved in integrating the Tiles framework with Struts2. Apache Tiles is a templating framework built to simplify the development of web application user interfaces. First of all we need to download the tiles jar files from the Apache Tiles website. You need to add the following jar files to the project's class path.

Now let us setup the web. There are two important point to note here. First, we need to tell tiles, where to find tiles configuration file tiles.