example3getcharactersaction.java

XMLHttpRequest实现AJAX.zip

package xhrstruts;


import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Iterator;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
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 Example3GetCharactersAction extends Action {


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

    // Get a list of characters associated with the select TV show
    String tvShow = (String)request.getParameter("tvShow");
    if (tvShow == null) {
      tvShow = "";
    }
    ArrayList characters = getCharacters(tvShow);

    // And yes, I know creating HTML in an Action is generally very bad form,
    // but I wanted to keep this exampel simple.
    String html = "<select name=\"CharactersSelect\">";
    int i = 0;
    for (Iterator it = characters.iterator(); it.hasNext();) {
      String name = (String)it.next();
      i++;
      html += "<option value=\"" + i + "\">" + name + "</option>";
    }
    html += "</select>";

    // Write the HTML to response
    response.setContentType("text/html");
    PrintWriter out = response.getWriter();
    out.println(html);
    out.flush();

    return null; // Not forwarding to anywhere, response is fully-cooked

  } // End execute()


  // This method returns a list of characters for a given TV show.  If no TV
  // show is selected, i.e., initial page view, am empty ArrayList is returned.
  private ArrayList getCharacters(String tvShow) {

    ArrayList al = new ArrayList();

    if (tvShow.equalsIgnoreCase("StarTrekTNG")) {
      al.add("Jean Luc Picard");
      al.add("William T. Riker");
      al.add("Data");
      al.add("Deanna Troi");
      al.add("Geordi LaForge");
    }

    if (tvShow.equalsIgnoreCase("Babylon5")) {
      al.add("John Sheridan");
      al.add("Delenn");
      al.add("Londo Mollari");
      al.add("Stephen Franklin");
      al.add("Vir Cotto");
    }

    if (tvShow.equalsIgnoreCase("StargateSG1")) {
      al.add("Samantha Carter");
      al.add("Jack O'Neil");
      al.add("Teal'c");
      al.add("Daniel Jackson");
      al.add("Baal");
    }

    return al;

  } // End getCharacters()


} // End class