Using WebObjects Classes in a JSP Page

This section explains how to write a JSP page that makes use of two WebObjects classes, NSArray and NSMutableArray, to pass information to a component called MusicGenres. You'll continue to work with the JSP_Example project.

Using a text editor, create a file with the contents of Listing 3-2.

Listing 3-2 InternetRadio.jsp file

<%-- InternetRadio.jsp --%>

<%@ taglib uri="/WOtaglib" prefix="wo" %>

<%-- Import statements --%>
<%@ page import="com.webobjects.foundation.*" %>
<%@ page import="com.webobjects.jspservlet.*" %>

<%-- Initialize JSP/servlet–WebObjects integration system --%>
<%
    WOServletAdaptor.initStatics(application);
%>

<%-- Create musical-genre list --%>
<%
    NSMutableArray genres = new NSMutableArray();
    genres.addObject(new String("Classical"));
    genres.addObject(new String("Country"));
    genres.addObject(new String("Eclectic"));
    genres.addObject(new String("Electronica"));
    genres.addObject(new String("Hard Rock/Metal"));
    genres.addObject(new String("Hip-Hop/Rap"));
    genres.addObject(new String("Jazz"));
%>

<HTML>

<HEAD>
    <TITLE>Music Available on Internet Radio Stations</TITLE>
</HEAD>

<BODY>
    <wo:component className="MusicGenres" bodyContentOnly="true">
        <wo:binding key="genres" value='<%= genres %>' />
    </wo:component>
</BODY>

</HTML>

Note the invocation of the initStatics method of the WOServletAdaptor class. It performs the initialization of objects needed to integrate WebObjects with your servlet container (for example, adding a WOSession object to the JSPSession object).

Save the file as InternetRadio.jsp in the JSP_Example/Servlet Resources/jsp directory.
In Project Builder, create a component called MusicGenres (make sure you assign it to the Application Server target).
Add the genres and genre keys to MusicGenres using WebObjects Builder. genres is an array of Strings and genre is a String. Add a setter method for genres.
Alternatively, you can add the following code to MusicGenres.java:
```
protected String genre;
    
/** @TypeInfo java.lang.String */
protected NSArray genres;

public void setGenres(NSArray newGenres) {
    genres = newGenres;
}
```
Edit the component using WebObjects Builder so that it looks like Figure 3-6.
Figure 3-6 The MusicGenres component in WebObjects Builder
Tell Project Builder to copy the necessary WebObjects classes to the WAR file.
1. In Project Builder click Targets, then click on the JSP_Example target in the Targets list.
2. Click Build Settings, then scroll down until you see the Build Settings list.
3. Locate the SERVLET_COPY_JARS build setting and set its value to YES , as shown in Figure 3-7.
  Figure 3-7 Telling Project Builder to copy WebObjects classes to the WAR file
Build the project and restart your servlet container.

To view the output of the InternetRadio JSP page in Tomcat use the following URL:

http://localhost:8080/JSP_Example/jsp/InternetRadio.jsp

You should see a page like the one in Figure 3-8.

Figure 3-8 The output of InternetRadio.jsp