Adobe Flex with Struts 2 using HttpService

Using HttpService is the easiest way in which you can integrate Adobe Flex and Struts 2. As an example I will show you how you can create a registration form in Adobe Flex which calls a struts 2 action to create new users. Note that this example is very simple and for demonstration purposes. I am not adding any validation in flex and not even creating the users in a database. All I show you is how you can pass data between flex and struts.

First let me show you the steps you need to perform in Adobe Flex:

Step 1

Create the registration form in mxml:

<mx:Form label="Registration Form">

 <mx:FormHeading label="Registration Form">

 </mx:FormHeading>

 <mx:FormItem label="First Name">

  <mx:TextInput id="firstName">

  </mx:TextInput>

 </mx:FormItem>

 <mx:FormItem label="Last Name">

  <mx:TextInput id="lastName">

  </mx:TextInput>

 </mx:FormItem>

 <mx:FormItem label="Email">

   <mx:TextInput id="email">

  </mx:TextInput>

 </mx:FormItem>

 <mx:FormItem label="Username">

  <mx:TextInput id="username">

  </mx:TextInput>

 </mx:FormItem>

 <mx:FormItem label="Password">

  <mx:TextInput id="password" displayAsPassword="true">

  </mx:TextInput>

 </mx:FormItem>

 <mx:FormItem>

  <mx:Button label="Register" click="registerUser()"/>

 </mx:FormItem>

</mx:Form>

Step 2

Create the HttpService object:

<mx:HTTPService id="registerService" showBusyCursor="true" useProxy="false" url="register.action" resultFormat="e4x" method="POST" result="registerConfirmation(event)" fault="registerFailed(event)"/>

• register.action is the Struts 2 action that registers the user
  
• registerConfirmation(event) is the function that is called if the http service call is successful.
  
• registerFailed(event) is the function that is called if an error occurs. For example if the server is down. The event object gives you access to any xml/html that might be returned upon the call of the action.
  
• resultFormat specifies in which format you want to view the results. It can be text, xml or an object. There are 5 possible values for this field:
  
  • object - An XML object is returned and is parsed as a tree of ActionScript objects
    
  • xml - Returns literal XML in an XMLNode object
    
  • e4x - Returns literal XML that can be accessed using ECMAScript for XML(E4X) expressions.
    
  • flashvars - The result is text in flashvars format, value pairs separated by ampersands. Flex returns this result in an actionscript object
    
  • array - The result is XML that is returned in an Array even if there is only one top level node.
  
  

Step 3

Write the actionscript call to submit the form:

public function registerUser():void {

      var params:Object = { 'user.firstName': firstName.text,'user.lastName': lastName.text, 'user.email':email.text, 'user.password':password.text }; 

      this.registerService.send(params);

}

Step 4

Create registerConfirmation(). This method checks whether the registration was successful. We can know that by inspecting the XML that is returned.

private function registerConfirmation(event:ResultEvent):void {

        var xml:XML=XML(event.result); 

 if (xml != null && xml.item == true) {

  mx.controls.Alert.show("Registration Successful!");

 }

 else {

  mx.controls.Alert.show("The registration was not successful.");

 }

 }}

Step 5

If we can't call the action on the server because of some networking issue we also should give some feedback to the user.

   

/**

 * Display a message to the user explaining what went wrong

 */

private function registerFailed(event:FaultEvent):void {

 mx.controls.Alert.show(event.fault.message);

}

Now let's create our Struts 2 Action:

Step 1

Create RegisterAction.java

package uk.co.spltech.web.actions;


import uk.co.spltech.beans.User;


import com.opensymphony.xwork2.ActionSupport;


/**

 * Creates a new user

 * 

 * @author Armindo Cachada

 *

 */

public class RegisterAction extends ActionSupport {


 private User user;

 

 private Boolean success;

 

 public Boolean getSuccess() {

  return success;

 }


 public void setSuccess(Boolean success) {

  this.success = success;

 }


 public User getUser() {

  return user;

 }


 public void setUser(User user) {

  this.user = user;

 }


 /**

  * Registers a user

  * 

  * @return

  */

 public String register() {

  System.out.println("Checking user");

  if ( this.getUser()!= null) {

   User u = this.getUser();

   if (u.getEmail()!= null && !u.getEmail().equals("") && u.getPassword()!= null 

     && !u.getPassword().equals("") ) {

    System.out.println("Successfully registered user with email=" + u.getEmail());

    this.success=true;

   }

   else {

    this.success=false;

    System.out.println("Error registering user");

   }

  }

  else {

   this.success=false;

   System.out.println("Error registering user");

  }

  

  return SUCCESS;


 }

 

}

Step 2

Add action name='register' to struts.xml

<package name="user" extends="struts-default">

        <action name="register" method="register" class="uk.co.spltech.web.actions.RegisterAction">

           <result type="xslt">   <param name="exposedValue">{success}</param></result>

        </action>

</package>

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출처: http://simplyolaf.blogspot.com/2009/07/adobe-flex-with-struts-2-using.html