ViralPatel.net » Struts

Struts displaytag tutorial: Sort / Pagination data using displaytag in Struts

Viral Patel — Tue, 09 Jun 2009 11:53:03 +0000

Struts display tag library is an open source suite of custom tags that provide high-level web presentation patterns which will work in an MVC model. The library provides a significant amount of functionality while still being easy to use. Displaytag can handle column display, sorting, paging, cropping, grouping, exporting, smart linking and decoration of a table in a customizable XHTML style.

In the following example we will see how to dispaly data using display tag and to do pagination and sorting. We will use Eclipse as an IDE for our example.

Step 1: Create Eclipse dynamic web project and copy JAR files

Start Eclipse and goto File -> New -> Project -> Dynamic Web Project

Following is the list of required JAR files to be added in Java Class Path of your project. Download displaytag JAR files from http://displaytag.sourceforge.net/1.2/download.html.

Step 2: Create Action, Form and Bean class

Once the project is created, create 3 java files ForbesData, UserAction and UserForm in package net.viralpatel.struts.displaytag.

Copy following content into ForbesData.java file.

package net.viralpatel.struts.displaytag;

import java.util.ArrayList;

public class ForbesData {
	private int rank;
	private String name;
	private int age;
	private double netWorth;

	public ForbesData() {

	}

	public ForbesData(int rank, String name, int age, double netWorth) {
		this.rank = rank;
		this.name = name;
		this.age = age;
		this.netWorth = netWorth;
	}
	public ArrayList loadData() {
		ArrayList userList = new ArrayList();
		userList.add(new ForbesData(1, "William Gates III", 53, 40.0));
		userList.add(new ForbesData(2, "Warren Buffett", 78, 37));
		userList.add(new ForbesData(3, "Carlos Slim Helu & family", 69, 35));
		userList.add(new ForbesData(4, "Lawrence Ellison", 64, 22.5));
		userList.add(new ForbesData(5, "Ingvar Kamprad & family", 83, 22));
		userList.add(new ForbesData(6, "Karl Albrecht", 89, 21.5));
		userList.add(new ForbesData(7, "Mukesh Ambani", 51, 19.5));
		userList.add(new ForbesData(8, "Lakshmi Mittal", 58, 19.3));
		userList.add(new ForbesData(9, "Theo Albrecht", 87, 18.8));
		userList.add(new ForbesData(10, "Amancio Ortega", 73, 18.3));
		userList.add(new ForbesData(11, "Jim Walton", 61, 17.8));
		userList.add(new ForbesData(12, "Alice Walton", 59, 17.6));
		userList.add(new ForbesData(12, "Christy Walton & family", 54, 17.6));
		userList.add(new ForbesData(12, "S Robson Walton", 65, 17.6));
		userList.add(new ForbesData(15, "Bernard Arnault", 60, 16.5));
		userList.add(new ForbesData(16, "Li Ka-shing", 80, 16.2));
		userList.add(new ForbesData(17, "Michael Bloomberg", 67, 16));
		userList.add(new ForbesData(18, "Stefan Persson", 61, 14.5));
		userList.add(new ForbesData(19, "Charles Koch", 73, 14));
		userList.add(new ForbesData(19, "David Koch", 68, 14));
		userList.add(new ForbesData(21, "Liliane Bettencourt", 86, 13.4));
		userList.add(new ForbesData(22, "Prince Alwaleed Bin Talal Alsaud", 54, 13.3));
		return userList;
	}
	public int getRank() {
		return rank;
	}
	public void setRank(int rank) {
		this.rank = rank;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public double getNetWorth() {
		return netWorth;
	}
	public void setNetWorth(double netWorth) {
		this.netWorth = netWorth;
	}
}

Copy following content into UserForm.java

package net.viralpatel.struts.displaytag;

import java.util.ArrayList;

public class UserForm extends org.apache.struts.action.ActionForm {

	private ArrayList forbesList;

	public ArrayList getForbesList() {
		return forbesList;
	}

	public void setForbesList(ArrayList forbesList) {
		this.forbesList = forbesList;
	}
}

Copy following content into UserAction.java

package net.viralpatel.struts.displaytag;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

public class UserAction extends Action {

    private final static String SUCCESS = "success";

	public ActionForward execute(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response)
            throws Exception {
        UserForm userForm = (UserForm) form;
        ForbesData actorData = new ForbesData();
        userForm.setForbesList(actorData.loadData());
        return mapping.findForward(SUCCESS);
    }

}

Step 3: Create JSPs, struts-config.xml and web.xml

Create index.jsp and user.jsp in WebContent folder and struts-config.xml and web.xml in WebContent/WEB-INF folder.

Copy following content into appropriate files.

index.jsp

<%@page contentType="text/html"%>
<%@page pageEncoding="UTF-8"%>

user.jsp


<%@taglib uri="http://displaytag.sf.net" prefix="display" %>

    
        
        The World's Billionaires 2009
        
    
    
    The World's Billionaires 2009 - Forbes List

struts-config.xml

web.xml



	
		action
		
			org.apache.struts.action.ActionServlet
		
		
			config
			/WEB-INF/struts-config.xml
		
		
			debug
			2
		
		
			detail
			2
		
		2
	
	
		action
		*.do
	
	
		30
	
	
		index.jsp

Step 4: Execute the project

We are done with the project. Now execute the project in eclipse or create a WAR file and run it in Tomcat.

Tutorial: Creating DynaActionForm example in Struts

Viral Patel — Wed, 11 Mar 2009 13:43:04 +0000

We learned in this tutorial about creating a basic web application in Struts, We had used Struts Frameworks ActionForm to manage the form data. Let us see how to use DynaActionForm to manage the form data.

DynaActionForm is also called as Dynamic Form Bean. These are extensions of Form Beans that allow you to specify their properties inside the struts configuration file instead of having to create a concrete class.

To create a DynaActionForm, we have to make following entry in struts-config.xml file.

While using ActionForm, we create an entry in struts-config.xml with tag. We specify the class name of ActionForm class.
In case of DynaActionForm, we create a dynamic form bean by specifying properties in struts-config.xml itself. In above code snippet we have created a login form with two properties: username and password. We have also provided its initial values.

Once you have define an entry for Form bean in struts-config.xml, you can use this form in any of your action using normal tag.

Hence when the login action will be called, the form data will be populated in DynaActionForm and bean object will be passed to execute() method of LoginAction.

To fetch the form data from Form object use get() method of DynaActionForm class.

public ActionForward execute(ActionMapping mapping, ActionForm form,
             HttpServletRequest request, HttpServletResponse response)
             throws Exception {  

	DynaActionForm dynaForm = (DynaActionForm)form;
	String userName = (String)dynaForm.get("username");
	String password = (String)dynaForm.get("password");
...
...
}

Creating & Parsing JSON data with Java Servlet/Struts/JSP

Viral Patel — Thu, 19 Feb 2009 10:34:07 +0000

JSON (JavaScript Object Notation) is a lightweight computer data interchange format. It is a text-based, human-readable format for representing simple data structures and associative arrays (called objects). The JSON format is specified in RFC 4627 by Douglas Crockford. The official Internet media type for JSON is application/json.

The JSON format is often used for transmitting structured data over a network connection in a process called serialization. Its main application is in AJAX web application programming, where it serves as an alternative to the traditional use of the XML format.

Supported data types

Number (integer, real, or floating point)
String (double-quoted Unicode with backslash escapement)
Boolean (true and false)
Array (an ordered sequence of values, comma-separated and enclosed in square brackets)
Object (collection of key/value pairs, comma-separated and enclosed in curly brackets)
null

Syntax

The following example shows the JSON representation of an object that describes a person. The object has string fields for first name and last name, contains an object representing the person’s address, and contains a list of phone numbers (an array).

{
    "firstName": "John",
    "lastName": "Smith",
    "address": {
        "streetAddress": "21 2nd Street",
        "city": "New York",
        "state": "NY",
        "postalCode": 10021
    },
    "phoneNumbers": [
        "212 732-1234",
        "646 123-4567"
    ]
}

Creating JSON data in Java

JSON.org has provided libraries to create/parse JSON data through Java code. These libraries can be used in any Java/J2EE project including Servlet, Struts, JSF, JSP etc and JSON data can be created.

Download JAR file json-rpc-1.0.jar (75 kb)

Use JSONObject class to create JSON data in Java. A JSONObject is an unordered collection of name/value pairs. Its external form is a string wrapped in curly braces with colons between the names and values, and commas between the values and names. The internal form is an object having get() and opt() methods for accessing the values by name, and put() methods for adding or replacing values by name. The values can be any of these types: Boolean, JSONArray, JSONObject, Number, and String, or the JSONObject.NULL object.

import org.json.JSONObject;

...
...

JSONObject json = new JSONObject();
json.put("city", "Mumbai");
json.put("country", "India");

...

String output = json.toString();

...

Thus by using toString() method you can get the output in JSON format.

JSON Array in Java

A JSONArray is an ordered sequence of values. Its external text form is a string wrapped in square brackets with commas separating the values. The internal form is an object having get and opt methods for accessing the values by index, and put methods for adding or replacing values. The values can be any of these types: Boolean, JSONArray, JSONObject, Number, String, or the JSONObject.NULL object.

The constructor can convert a JSON text into a Java object. The toString method converts to JSON text.

JSONArray class can also be used to convert a collection of Java beans into JSON data. Similar to JSONObject, JSONArray has a put() method that can be used to put a collection into JSON object.

Thus by using JSONArray you can handle any type of data and convert corresponding JSON output.

Using json-lib library

JSON-lib is a java library for transforming beans, maps, collections, java arrays and XML to JSON and back again to beans and DynaBeans.

Json-lib comes in two flavors, depending on the jdk compatibility. json-lib-x.x-jdk13 is compatible with JDK 1.3.1 and upwards. json-lib-x.x-jdk15 is compatible with JDK 1.5, includes support for Enums in JSONArray and JSONObject.

Download: json-lib.jar

Json-lib requires (at least) the following dependencies in your classpath:

Example

package net.viralpatel.java;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import net.sf.json.JSONObject;

public class JsonMain {
	public static void main(String[] args) {

		Map map = new HashMap();
		map.put("A", 10L);
		map.put("B", 20L);
		map.put("C", 30L);

		JSONObject json = new JSONObject();
		json.accumulateAll(map);

		System.out.println(json.toString());

		List list = new ArrayList();
		list.add("Sunday");
		list.add("Monday");
		list.add("Tuesday");

		json.accumulate("weekdays", list);
		System.out.println(json.toString());
	}
}

Output:

{"A":10,"B":20,"C":30}
{"A":10,"B":20,"C":30,"weekdays":["Sunday","Monday","Tuesday"]}

Using Google Gson library

Gson is a Java library that can be used to convert Java Objects into their JSON representation. It can also be used to convert a JSON string to an equivalent Java object. Gson can work with arbitrary Java objects including pre-existing objects that you do not have source-code of.

There are a few open-source projects that can convert Java objects to JSON. However, most of them require that you place Java annotations in your classes; something that you can not do if you do not have access to the source-code. Most also do not fully support the use of Java Generics. Gson considers both of these as very important design goals.

Gson Goals

Provide simple toJson() and fromJson() methods to convert Java objects to JSON and vice-versa
Allow pre-existing unmodifiable objects to be converted to and from JSON
Extensive support of Java Generics
Allow custom representations for objects
Support arbitrarily complex objects (with deep inheritance hierarchies and extensive use of generic types)

Google Gson Example

import java.util.List;
import com.google.gson.Gson;

public class Test {

    public static void main(String... args) throws Exception {
        String json =
            "{"
                + "'title': 'Computing and Information systems',"
                + "'id' : 1,"
                + "'children' : 'true',"
                + "'groups' : [{"
                    + "'title' : 'Level one CIS',"
                    + "'id' : 2,"
                    + "'children' : 'true',"
                    + "'groups' : [{"
                        + "'title' : 'Intro To Computing and Internet',"
                        + "'id' : 3,"
                        + "'children': 'false',"
                        + "'groups':[]"
                    + "}]"
                + "}]"
            + "}";

        // Now do the magic.
        Data data = new Gson().fromJson(json, Data.class);

        // Show it.
        System.out.println(data);
    }

}

class Data {
    private String title;
    private Long id;
    private Boolean children;
    private List groups;

    public String getTitle() { return title; }
    public Long getId() { return id; }
    public Boolean getChildren() { return children; }
    public List getGroups() { return groups; }

    public void setTitle(String title) { this.title = title; }
    public void setId(Long id) { this.id = id; }
    public void setChildren(Boolean children) { this.children = children; }
    public void setGroups(List groups) { this.groups = groups; }

    public String toString() {
        return String.format("title:%s,id:%d,children:%s,groups:%s", title, id, children, groups);
    }

Struts Validation Framework Tutorial with example.

Viral Patel — Thu, 22 Jan 2009 06:30:47 +0000

Apache Struts has changed the way we develop a Web application. Since its inception as an MVC architecture, Struts has been extensively used in J2EE world to develop robust, extendable and effective web applications.

Introduction to Struts Validation Framework

One of the important features of Struts framework is Struts Validation framework that performs validation on incoming form data. Validation framework was introduced by David Winterfeldt as an external plugin to Struts framework. It’s functionality has since been split so that validator can serve as the basis for a independant component and is now part of Jakarta Commons.

The Struts framework’s simple validation interface alleviates much of the headache associated with handling data validation, allowing you to focus on validation code and not on the mechanics of capturing data and redisplaying incomplete or invalid data.

In order to do form validation without Validator framework, one has to use validate() method of the form bean (ActionForm class) to perform this task. Also one has to handle error messages during manual validation. Lot of fields that we validate require same logic to validate them, hence code is unneccessarily duplicated (if not managed properly).

Validation framework comes with set of useful routines to handle form validation automatically and it can handle both server side as well as client side form validation. If certain validation is not present, you can create your own validation logic and plug it into validation framework as a re-usable component.

Validator uses two XML configuration files to determine which validation routines should be installed and how they should be applied for a given application, respectively. The first configuration file, validator-rules.xml, declares the validation routines that should be plugged into the framework and provides logical names for each of the validations. The validator-rules.xml file also defines client-side JavaScript code for each validation routine. Validator can be configured to send this JavaScript code to the browser so that validations are performed on the client side as well as on the server side.

The second configuration file, validation.xml, defines which validation routines should be applied to which Form Beans. The definitions in this file use the logical names of Form Beans from the struts-config.xml file along with the logical names of validation routines from the validator-rules.xml file to tie the two together.

Using the Validator framework involves enabling the Validator plug-in, configuring Validator’s two configuration files, and creating Form Beans that extend the Validator’s ActionForm subclasses. The following sections explain in detail how to configure and use Validator.

Create a Struts project

Create a struts web application project. I assume you have working environment set for a Struts project. If not then go through the tutorial: Creating Struts application using Eclipse and create a struts project.

Create Form Beans

Create a form bean in your project called CustomerForm and copy following code in it.

package net.viralpatel.struts.validation.form;

import org.apache.struts.validator.ValidatorForm;

public class CustomerForm extends ValidatorForm {

	private String name;
	private String telephone;
	private String email;
	private int age;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getTelephone() {
		return telephone;
	}

	public void setTelephone(String telephone) {
		this.telephone = telephone;
	}

	public String getEmail() {
		return email;
	}

	public void setEmail(String email) {
		this.email = email;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}
}

We will use this validator plugin to validate this form. Note that the form bean is extended from class ValidatorForm and not ActionForm as we generally do in Struts project.

Add Validator Plug-in in struts-config.xml

In order to use Validator in our project we need to configure it in struts-config.xml file. For this add following code in your struts-config.xml file.

This definition tells Struts to load and initialize the Validator plug-in for your application. Upon initialization, the plug-in loads the comma-delimited list of Validator config files specified by the pathnames property. Each config file’s path should be specified by use of a Web application-relative path, as shown in the previous example.

Define validations for the form

Create a file validation.xml in your applications WEB-INF directory. And copy following content in it.





	
	telephoneFormat
	^\d{5,10}$
	


	
		
			
		
		
			
			
			
			
				min
				1
			
			
				max
				125
			
		
		
			
			
			
				mask
				${telephoneFormat}

In the above xml file, we have defined the rules for form validation. Note that we are validating form CustomerForm and the fields being validated are name, age, telephone and email. tag defines the validation for a property of form. We can specify different rules like required, integer, email, intRange, mask etc in depends attribute of field tag..

Also you can define constants that can be reused in the validation xml using global constants tag.

Struts-config.xml entry for the action

Following is the entry in struts-config.xml file which maps the Action to our Validator form.


	

...
...
...

...
	
		
		
	
...

Configuring ApplicationResources.properties

Struts validation framework uses externalization of the error messages. The messages are stored in a property file (ApplicationResource.properties) and are referred by the key values. Copy following in your ApplicationResource.properties (or MessageResource.properties).

label.name= Name
label.email= Email
label.telephone= Telephone
label.age= Age

# general error msgs
errors.header=
errors.prefix=
errors.suffix=
errors.footer=
errors.invalid={0} is invalid.
errors.maxlength={0} can not be greater than {1} characters.
errors.minlength={0} can not be less than {1} characters.
errors.range={0} is not in the range {1} through {2}.
errors.required={0} is required.
errors.byte={0} must be an byte.
errors.date={0} is not a date.
errors.double={0} must be an double.
errors.float={0} must be an float.
errors.integer={0} must be an integer.
errors.long={0} must be an long.
errors.short={0} must be an short.

Create JSP to display the form

Create a JSP file called index.jsp and copy following content in it.

<%@ taglib uri="http://struts.apache.org/tags-html" prefix="html"%>
<%@ taglib uri="http://struts.apache.org/tags-bean" prefix="bean"%>


Struts Validation Framework example.

Running the application

We are done with our application. Now execute it from any web container (Tomcat in my case) and open in browser.

Enter any invalid value in the form and press submit.

Post your comments / doubts on this tutorial.

Struts DispatchAction Tutorial with Example in Eclipse.

Viral Patel — Fri, 16 Jan 2009 11:00:22 +0000

Are you bugged of creating separate action classes for some common set of functionality in your Struts application? Feeling pain in managing all those hundreds of Action classes in your project? Don’t worry, cheers..!! DispatchAction is for you.

DispatchAction is one of the Struts built-in action that provides a mechanism that facilitates having a set of related functionality in a single action instead of creating separate independent actions for each function.

Let us create a sample example that uses DispatchAction and implement certain functionality of our project. Before that, I assume you have working knowledge of Struts application. If you don’t, Read this tutorial about A Hello World Struts project and get some basics about Struts application.

Also, I assume you have already got a Struts application and you want to add Dispatch Action into it. So let us start with our example.

Step 1: Create DispatchAction class file.

Create an Action class called UserManagementAction and extend it with class org.apache.struts.actions.DispatchAction. Copy following code into it.

package net.viralpatel.struts.helloworld.action;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.actions.DispatchAction;

public class UserManagementAction extends DispatchAction {

	public ActionForward create(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {

		request.setAttribute("message", "User created successfully");

		return mapping.findForward("success");
	}

	public ActionForward delete(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {

		request.setAttribute("message", "User deleted successfully");

		return mapping.findForward("success");
	}

	public ActionForward update(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {

		request.setAttribute("message", "User updated successfully");

		return mapping.findForward("success");
	}

	public ActionForward block(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {

		request.setAttribute("message", "User blocked successfully");

		return mapping.findForward("success");
	}
}

In above code, we have created separate methods (create(), delete(), update() and block()) for each functionality. Also note that the method signature of these methods are exactly similar to the execute() method of Action class file.

public ActionForward delete(ActionMapping mapping, ActionForm form,
		HttpServletRequest request, HttpServletResponse response)
		throws Exception { }

Step 2: Create a mapping for action in struts-config.xml file.

Open your struts-config.xml and copy following action mapping entry in it.

We have added an extra attribute in tag, parameter=”parameter”. DispatchAction will read a request parameter called “parameter” and its value will decide the method to be called. Suppose you have a request parameter “parameter” with value “create”, Dispatch Action will call create() method from your Action file.

Step 3: Create JSPs for viewing the application.

Create two JSP files UserManagement.jsp and UserSuccess.jsp and copy following code into it. UserManagement.jsp will display a menu for selecting action to be taken. UserSuccess.jsp will just print the appropriate action taken by the Action class.

UserManagement.jsp

<%@taglib uri="http://jakarta.apache.org/struts/tags-html" prefix="html"%>


	Dispatch Action Example - viralpatel.net


	User Management (Dispatch Action Example)

	Create User
	 |
	Delete User
	 |
	Update User
	 |
	Block User

UserSuccess.jsp

<%@taglib uri="http://jakarta.apache.org/struts/tags-html" prefix="html"%>


	Dispatch Action Example - viralpatel.net


	User Message (Dispatch Action Example)
	
	<%= request.getAttribute("message") %>

In UserManagement.jsp, we have created links using tag and passed a parameter “parameter” with values create, delete, block etc. This value is fetched by the Dispatch Action and is used to call corresponding method in Action class. Thus if we click Update User link, a parameter update will be passed to the action class and corresponding update() method will be called by framework.

Step 4: Run the application.

Compile and Run the project using Eclipse or Ant and open UserManagement.jsp file in your favorite browser.

Click the link Create User or Delete User etc. and see the output.

Tutorial: Struts File Upload Example.

Viral Patel — Mon, 22 Dec 2008 09:21:08 +0000

Let us see how we can implement file upload functionality using Apache Struts Framework. I assume you have basic knowledge about Struts and know the flow of a struts application. If you are new to struts, I suggest you to check this tutorial first: Struts Project in Eclipse.

First let us download all the required JAR files to implement file upload functionality. For this we will need common-fileupload.jar file that comes with common package of Struts.
Download common-fileupload.jar (version 1.0, size 20 kb).

Include this JAR file in your class path variable.

Now, modify the ActionForm class where you want to add File upload functionality and add following property and its getter and setter methods.

import org.apache.struts.upload.FormFile;
....
....
	private FormFile file;

	public FormFile getFile() {
		return file;
	}

	public void setFile(FormFile file) {
		this.file = file;
	}
....
....

In the above code snippet, we have added an attribute file which is of type org.apache.struts.upload.FormFile. This property will contain file content and other file related information that is being upload from form.

Now add following code in your JSP page to add a file upload input.


....
....
	
....
....

Note that in above code we added method=”post” and enctype=”multipart/form-data” to the form. Also the name of property is same as what we mentioned in ActionForm class.

Now in the action file where you normally deal with form data, add following code to get information about the file being submitted.

//Type cast form to FileUploadForm.
FileUploadForm fileForm = (FileUploadForm)form;

//Get the FormFile object from ActionForm.
FormFile file = fileForm.getFile();

//Get file name of uploaded file.
String fileName = file.getFileName();

//Get file size of uploaded file.
Integer fileSize = file.getFileSize();

//The content type of the uploaded file.
String contentType = file.getContentType();

// Get InputStream object of uploaded File.
InputStream inputFile = file.getInputStream();

Once you get InputStream object, you can use normal file I/O to write the file anywhere on server.

Tutorial:Struts Spring framework example in Eclipse.

Viral Patel — Tue, 16 Dec 2008 10:27:13 +0000

Let us see how to add Spring support (Spring IOC) to a Struts application using Eclipse IDE. I will use the hello world struts project that we created in this tutorial as base reference and step by step we will add Spring support to it.

In this tutorial we will use Spring IOC (Inversion Of Control) mechanism. There will be a business delegate class that will be used to authenticate user. In Login class we will inject this BusinessDelegate class using Spring Injection. Let us start with tutorial.

First, Download required JAR file required for setting Spring support to our Struts application. For this we will need Spring.jar.
Download it from here (Spring.jar, version 1.1, 985kb).
You can download latest JAR file from Spring frameworks download page.

Copy spring.jar file in WEB-INF/lib folder of our struts project.

Now open your struts-config.xml from WEB-INF folder and add following entry for plugin in it. This will add Spring support to your struts project.

Create an xml file called ApplicationContext.xml in WEB-INF directory.

Copy following content in ApplicationContext.xml file.

Note that in this example we are using Spring framework to instantiate an object of BusinessDelegate class as well as LoginAction class and injecting this object of BusinnessDelegate in LoginAction.
So create a package net.viralpatel.struts.helloworld.business and create a java file BusinessDelegate.java in it.

Copy following code for login validation in BusinessDelegate class.

package net.viralpatel.struts.helloworld.business;

public class BusinessDelegate {

	public String validateUser(String userName, String password) {
		if(userName.equals("admin") && password.equals("123")) {
			return "success";
		}

		return "failure";
	}
}

Also add a property for BusinessDelegate class in LoginAction and its getter and setter method. This property will get injected by Spring. Copy/Paste following code in your LoginAction.java file.

package net.viralpatel.struts.helloworld.action;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import net.viralpatel.struts.helloworld.business.BusinessDelegate;
import net.viralpatel.struts.helloworld.form.LoginForm;

import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

public class LoginAction extends Action {

	private BusinessDelegate businessDelegate;

	public BusinessDelegate getBusinessDeletage() {
		return businessDelegate;
	}

	public void setBusinessDelegate(BusinessDelegate businessDeletage) {
		this.businessDelegate = businessDeletage;
	}

	public ActionForward execute(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {

		String target = null;
		LoginForm loginForm = (LoginForm)form; 

		target = businessDelegate.validateUser(loginForm.getUserName(),
												loginForm.getPassword());

		return mapping.findForward(target);
	}
}

Note that LoginAction class is also instantiate using Spring. Hence we will modify entry in struts-config.xml.

In type attribute, instead of LoginAction, we have used org.springframework.web.struts.DelegatingActionProxy. This is spring framework class that will delegate the call to action to specific class in ApplicationContext.xml file. Note that path=”/login” should match to name=”/login” entry that we made in ApplicationContext.xml file.

And that’s it. We have just implemented Spring support to our struts application.

You can download war file of struts-spring application with full source here. SOURCE CODE

Tutorial: Struts Tiles plugin example in Eclipse

Viral Patel — Mon, 08 Dec 2008 07:08:42 +0000

In the previous tutorials about Creating Struts application in Eclipse, we saw step by step how we can create a Struts project. In this tutorial we will explore Tiles plugin in struts.

Introduction of Tiles Plugin

Nowadays, website are generally divided into pieces of reusable template that are being rendered among different web pages. For example a site containing header, footer, menu etc. This items remains same through out the website and give it a common look and feel. It is very difficult to hard code this in each and every webpage and if later a change is needed than all the pages needs to be modified. Hence we use templatization mechanism. We create a common Header, Footer, Menu page and include this in each page.

Tiles Plugin allow both templating and componentization. In fact, both mechanisms are similar: you
define parts of page (a “Tile”) that you assemble to build another part or a full page. A part can
take parameters, allowing dynamic content, and can be seen as a method in JAVA language.

Installing Tiles

The Tiles installation process depends on the Struts version you use. If you start a new project,
use the latest Struts version. Tiles can also be used without Struts.

Add following entry of plug-in tag to your struts-config.xml in order to configure Tiles.

In this entry you can see definitions-config parameter which is set to the value /WEB-INF/tiles-definitions.xml. So we have to create a file called tiles-definitions.xml in WEB-INF directory.

Creating Application

We will create a Header and a Footer that we will integrate with our sturts application. We will render this header and footer using Tiles.
Create two JSPs, Header.jsp and Footer.jsp and copy following content in it.

Header.jsp


	Tiles Plugin Example using Struts &amp;amp;amp; Eclipse

Footer.jsp


	Copyright &amp;amp;amp;copy viralpatel.net

Also, create a Layout.jsp file in your WebContent folder and copy following code in it.

<%@ page contentType="text/html;charset=UTF-8" language="java"%>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-html" prefix="html"%>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-tiles" prefix="tiles"%>



		<tiles:getAsString name="title" />

Layout.jsp file will define overall layout of web page. I have used a table based layout here. You can use a DIV based layout and align all the components using CSS.
Note that we have used a tag in order to place the respective elements on this page. This will be more clear once you create tiles-definitions.xml file.

Now copy following code in tiles-plugins.xml file.

Here we have replace names like title, body, header, footer etc with the content of the JSPs. Hence tiles will replace the tag with appropriate content in Layout.jsp.

Tutorial: Creating Struts application in Eclipse

Viral Patel — Thu, 04 Dec 2008 13:35:47 +0000

Note: If you looking for tutorial “Create Struts2 Application in Eclipse” Click here.
In this tutorial we will create a hello world Struts application in Eclipse editor. First let us see what are the tools required to create our hello world Struts application.

JDK 1.5 above (download)
Tomcat 5.x above or any other container (Glassfish, JBoss, Websphere, Weblogic etc) (download)
Eclipse 3.2.x above (download)
Apache Struts JAR files:(download). Following are the list of JAR files required for this application.
- struts.jar
- common-logging.jar
- common-beanutils.jar
- common-collections.jar
- common-digester.jar

We will implement a web application using Struts framework which will have a login screen. Once the user is authenticated, (s)he will be redirected to a welcome page.

Let us start with our first struts based web application.

Open Eclipse and goto File -> New -> Project and select Dynamic Web Project in the New Project wizard screen.

After selecting Dynamic Web Project, press Next.

Write the name of the project. For example StrutsHelloWorld. Once this is done, select the target runtime environment (e.g. Apache Tomcat v6.0). This is to run the project inside Eclipse environment. After this press Finish.

Once the project is created, you can see its structure in Project Explorer.

Now copy all the required JAR files in WebContent -> WEB-INF -> lib folder. Create this folder if it does not exists.

Next step is to create a servlet entry in web.xml which points to org.apache.struts.action.ActionServlet class of struts framework. Open web.xml file which is there under WEB-INF folder and copy paste following code.


		action
		
			org.apache.struts.action.ActionServlet
		
		
			config
			/WEB-INF/struts-config.xml
		
		1


	action
	*.do

Here we have mapped url *.do with the ActionServlet, hence all the requests from *.do url will be routed to ActionServlet; which will handle the flow of Struts after that.

We will create package strutcures for your project source. Here we will create two packages, one for Action classes (net.viralpatel.struts.helloworld.action) and other for Form beans(net.viralpatel.struts.helloworld.action).

Also create a class LoginForm in net.viralpatel.struts.helloworld.action with following content.

package net.viralpatel.struts.helloworld.form;

import javax.servlet.http.HttpServletRequest;
import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionMessage;

public class LoginForm extends ActionForm {

	private String userName;
	private String password;

	public ActionErrors validate(ActionMapping mapping,
			HttpServletRequest request) {

		ActionErrors actionErrors = new ActionErrors();

		if(userName == null || userName.trim().equals("")) {
			actionErrors.add("userName", new ActionMessage("error.username"));
		}
		try {
		if(password == null || password.trim().equals("")) {
			actionErrors.add("password", new ActionMessage("error.password"));
		}
		}catch(Exception e) {
			e.printStackTrace();
		}
		return actionErrors ;
	}

	public String getUserName() {
		return userName;
	}
	public void setUserName(String userName) {
		this.userName = userName;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
}

LoginForm is a bean class which extends ActionForm class of struts framework. This class will have the string properties like userName and password and their getter and setter methods. This class will act as a bean and will help in carrying values too and fro from JSP to Action class.
Let us create an Action class that will handle the request and will process the authentication. Create a class named LoginAction in net.viralpatel.struts.helloworld.action package. Copy paste following code in LoginAction class.

package net.viralpatel.struts.helloworld.action;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import net.viralpatel.struts.helloworld.form.LoginForm;

import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

public class LoginAction extends Action {

	public ActionForward execute(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {

		String target = null;
		LoginForm loginForm = (LoginForm)form; 

		if(loginForm.getUserName().equals("admin")
				&& loginForm.getPassword().equals("admin123")) {
			target = "success";
			request.setAttribute("message", loginForm.getPassword());
		}
		else {
			target = "failure";
		}

		return mapping.findForward(target);
	}
}

In action class, we have a method called execute() which will be called by struts framework when this action will gets called. The parameter passed to this method are ActionMapping, ActionForm, HttpServletRequest and HttpServletResponse. In execute() method we check if username equals admin and password is equal to admin123, user will be redirected to Welcome page. If username and password are not proper, then user will be redirected to login page again.

We will use the internationalization (i18n) support of struts to display text on our pages. Hence we will create a MessagesResources properties file which will contain all our text data. Create a folder resource under src (Right click on src and select New -> Source Folder). Now create a text file called MessageResource.properties under resources folder.

Copy the following content in your Upadate:struts-config.xml MessageResource.properties file.

label.username = Login Detail
label.password = Password
label.welcome = Welcome

error.username =Username is not entered.

Create two JSP files, index.jsp and welcome.jsp with the following content in your WebContent folder.

index.jsp

<%@taglib uri="http://jakarta.apache.org/struts/tags-html" prefix="html"%>
<%@taglib uri="http://jakarta.apache.org/struts/tags-bean" prefix="bean" %>


	
		
		Login page | Hello World Struts application in Eclipse
	
	
	Login

welcome.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>


	
		
		Welcome page | Hello World Struts application in Eclipse
	
	
	<%
		String message = (String)request.getAttribute("message");
	%>
		Welcome <%= message %>

Now create a file called struts-config.xml in WEB-INF folder. Also note that in web.xml file we have passed an argument with name config to ActionServlet class with value /WEB-INF/struts-config.xml.

Following will be the content of struts-config.xml file:

And, that’s it .. We are done with our application and now its turn to run it. I hope you have already configured Tomcat in eclipse. If not then:

Open Server view from Windows -> Show View -> Server. Right click in this view and select New -> Server and add your server details.
To run the project, right click on Project name from Project Explorer and select Run as -> Run on Server (Shortcut: Alt+Shift+X, R)

Login Page

Welcome Page

Related: Create Struts 2 Application in Eclipse

Implementing Clean URL in Struts

Viral Patel — Tue, 02 Dec 2008 06:35:54 +0000

The web application created by using Struts framework can be easily identified by the URL patterns. Mostly all the Struts application have *.do or *.action URL depending on the version of Struts being used and the best practices that are followed.

These URLs are less search engine friendly as they reveal very little about the content. Hence it can be useful to implement a web application with clean URLs pattern such as /custormer/add or /profile/william.

This can be achieved in Struts by modifying Web.xml and struts-config.xml files. Following is the ActionServlet entry that is normally made in Web.xml file in order to configure struts.


action
org.apache.struts.action.ActionServlet

config
/WEB-INF/struts-config.xml


debug
2


detail
2

2



action
*.do

Thus, whenever the client request comes, the container match the pattern *.do in the URL and invokes the ActionServlet class which handles the rest of flow in Struts application. In order to use clean URL, make following entry for ActionServlet in your Web.xml file.


action

org.apache.struts.action.ActionServlet


config
/WEB-INF/struts-config.xml


debug
2


detail
2


chainConfig

org/apache/struts/tiles/chain-config.xml


2




default
*.css


default
*.js


default
*.png


default
*.jpg


default
/index.jsp


action
/

Please note that here the URL pattern that is mapped to ActionServlet class is not *.do and is / i.e. all the requests that comes will be routed to ActionServlet by the container. Also, URL patterns such as *.js, *.jpg, *.png, *.css etc are mapped to a servlet called default. This ensures that the static content are served to client without getting redirected to ActionServlet. Thus if you have other static content in your website, don’t forget to make an entry here and map it to default servlet. For example, I may have some *.zip files that I want to my users to download. Hence I will create an entry for *.zip and map it to default servlet in Web.xml file.

Once this is done, all the requests (except for static content) will get routed to ActionServlet.

Now, we will make normal entries for Action class in struts-config.xml file. Each entry will have a unique URL pattern that maps to an Action class.

Thus, whenever client request for a URL /login, LoginAction will be invoked by Struts framework. It is sometimes desirable to achieve clean url where request parameters are passed. For example, in some application /profile/john will point to Profile page of user John and /profile/william will point to that of William.

This can be achieved by using parametrized struts-config entries for actions. For example.

We have mapped a URL pattern /profile/* to ProfileAction. Thus whenever client will request for pages such as /profile/john or /profile/william, ProfileAction will gets invoked by Struts. Also note that we have used a parameter=”{1}” attribute in tag. This will pass whatever string that comes as * in /profile/* to Action class. This parameter can be fetched in Action class from mapping object of ActionMapping class which is passed as method argument in execute() method of Action.

public ActionForward process(ActionMapping mapping, ActionForm actionForm,
HttpServletRequest request, HttpServletResponse response)
throws NoRecordFoundException {

String parameter = mapping.getParameter();
...
}

Also, more than one parameter can be passed into the action for URLs like /profile/john/friends or /profile/john/groups. Thus to acheive this, URL /profile/*/* is mapped to Action and parameter=”{1}${2}” attribute will be added to action tag. Once the parameter is retrived in Action class using mapping.getParameter(), it has to split using $ separator as $ is used to concatenate {1} and {2} arguments.

Comments and queries invited

ViralPatel.net » Struts

Struts displaytag tutorial: Sort / Pagination data using displaytag in Struts

Step 1: Create Eclipse dynamic web project and copy JAR files

Step 2: Create Action, Form and Bean class

Step 3: Create JSPs, struts-config.xml and web.xml

index.jsp

user.jsp

The World's Billionaires 2009 - Forbes List

struts-config.xml

web.xml

Step 4: Execute the project

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<%= request.getAttribute("message") %>

Step 4: Run the application.

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Login

Welcome <%= message %>

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