4. Example 03 – Navigation Keys

4.1. The NetBeans project

in [1]:
[web.xml]: the web application configuration file
[struts.xml]: the Struts configuration file
[Action1.java]: the application’s single action
[Page1.jsp, Page2.jsp]: the two views of the application
in [2]: display of [Page1.jsp]
in [3]: display of [Page2.jsp]

4.2. The [struts.xml] file

It is as follows:


<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
        "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
        "http://struts.apache.org/dtds/struts-2.0.dtd">

<struts>
  <package name="default" namespace="/" extends="struts-default">
    <default-action-ref name="index" />
    <action name="index">
      <result type="redirectAction">
        <param name="actionName">Action1</param>
        <param name="namespace">/actions</param>
      </result>
    </action>
  </package>
  <package name="actions" namespace="/actions" extends="struts-default">
    <action name="Action1" class="actions.Action1">
      <result name="page1">/views/Page1.jsp</result>
      <result name="page2">/views/Page2.jsp</result>
    </action>
  </package>
</struts>

lines 17-19: the execute method of [Action1] will return two navigation keys:
page1, which will display the view /views/Page1.jsp
page2, which will display the view /views/Page2.jsp

4.3. The [Action1] action

It is similar to the one in the previous example:


package actions;

import com.opensymphony.xwork2.ActionSupport;

public class Action1 extends ActionSupport{
  
  // action model
  private String param1 = "value1";
  private String param2 = "value2";
  
  @Override
  public String execute(){
    // Random choice between two views
    int i = (int) Math.random() * 2;
    if(i==0){
      return "page1";
    } else {
      return "page2";
    }
  }
  
  // getters and setters
...
}

lines 12–14: The execute method randomly returns the expected keys page1 and page2.

4.4. The JSP views

Page1.jsp


<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags" %>
<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Page1</title>
  </head>
  <body>
    <h1>Page1</h1>
    param1=<s:property value="param1"/><br/>
  </body>
</html>

Line 11: The page displays the value of the param1 field from [Action1].

Page2.jsp


<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags" %>
<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Page 2</title>
  </head>
  <body>
    <h1>Page2</h1>
    param2=<s:property value="param2"/><br/>
  </body>
</html>

Line 11: The page displays the value of the param2 field from [Action1].

4.5. Testing

Once one of the pages is in the browser, you must refresh it (F5) to repeatedly execute the [Action1] action until the other page appears. You can also pass parameters: