package servlets;
import java.io.*;
import java.text.DecimalFormat;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
/**
* Implements a survey of favorite pets
*/
public class SurveyServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private static final String animalNames[] = { "dog", "cat", "bird", "snake", "fish",
"other", "none" };
/**
* @see HttpServlet#HttpServlet()
*/
public SurveyServlet() {
super();
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
int votesForAnimals[] = null;
int totalVotes = 0;
String userChoice = request.getParameter("animal");
// now send a thanks to the client and the results
response.setContentType("text/html");
String docType = "";
String html = "\n";
// get the output stream for the client
PrintWriter clientOutput = response.getWriter();
// generate the response document
clientOutput.println(docType);
clientOutput.println(html);
// Error: return an error response to the user
if (userChoice == null) {
clientOutput.println("Error!");
clientOutput.println("");
clientOutput.println("Ooops!
");
clientOutput.println("Error: Please submit a choice for animal.
");
clientOutput.println("Return to Pet Survey
");
clientOutput.println("\n");
clientOutput.close();
return;
}
// read in the survey results so far
File surveyData = new File("survey.results");
if (surveyData.exists()) {
try {
ObjectInputStream in = new ObjectInputStream(new FileInputStream(surveyData));
votesForAnimals = (int[]) in.readObject();
in.close();
for (int x = 0; x < votesForAnimals.length; x++)
totalVotes += votesForAnimals[x];
} catch (ClassNotFoundException exp) {
System.err.println("Error reading in file" + surveyData);
}
} else {
votesForAnimals = new int[animalNames.length];
}
// read current response (that caused this to run)
totalVotes++;
// determine which was selected and update the total
for (int x = 0; x < animalNames.length; x++) {
if (userChoice.equals(animalNames[x])) {
votesForAnimals[x]++;
break;
}
}
// write updated total to the file
ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(surveyData));
out.writeObject(votesForAnimals);
out.flush();
out.close();
// determine percentages
double percentages[] = new double[votesForAnimals.length];
for (int x = 0; x < percentages.length; x++)
percentages[x] = 100.0 * votesForAnimals[x] / totalVotes;
clientOutput.println("Thank You!");
clientOutput.println("");
clientOutput.println("Thank you for your input!
");
clientOutput.println("Results:
");
DecimalFormat twoDigits = new DecimalFormat("#0.00");
clientOutput.println("");
for (int x = 0; x < percentages.length; x++) {
clientOutput.println("| ");
clientOutput.println(animalNames[x] + " | ");
clientOutput.println(twoDigits.format(percentages[x]));
clientOutput.println(" | " + votesForAnimals[x] + " |
|---|
");
}
clientOutput.println("
");
clientOutput.println("Total Responses: ");
clientOutput.println(totalVotes + "
");
clientOutput.println("\n