📄 servletdemo2.java
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/* -----------------
* ServletDemo2.java
* -----------------
* (C) Copyright 2002-2004, by Object Refinery Limited.
*
*/
package demo;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* A basic servlet that generates an HTML page that displays a chart generated by
* JFreeChart.
* <P>
* This servlet uses another servlet (ServletDemo2ChartGenerator) to create a PNG image
* for the embedded chart.
* <P>
* This class is described in the JFreeChart Developer Guide.
*/
public class ServletDemo2 extends HttpServlet {
/**
* Creates a new servlet demo.
*/
public ServletDemo2() {
// nothing required
}
/**
* Processes a POST request.
* <P>
* The chart.html page contains a form for generating the first request, after that
* the HTML returned by this servlet contains the same form for generating subsequent
* requests.
*
* @param request the request.
* @param response the response.
*
* @throws ServletException if there is a servlet related problem.
* @throws IOException if there is an I/O problem.
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
PrintWriter out = new PrintWriter(response.getWriter());
try {
String param = request.getParameter("chart");
response.setContentType("text/html");
out.println("<HTML>");
out.println("<HEAD>");
out.println("<TITLE>JFreeChart Servlet Demo 2</TITLE>");
out.println("</HEAD>");
out.println("<BODY>");
out.println("<H2>JFreeChart Servlet Demo</H2>");
out.println("<P>");
out.println("Please choose a chart type:");
out.println("<FORM ACTION=\"ServletDemo2\" METHOD=POST>");
String pieChecked = (param.equals("pie") ? " CHECKED" : "");
String barChecked = (param.equals("bar") ? " CHECKED" : "");
String timeChecked = (param.equals("time") ? " CHECKED" : "");
out.println("<INPUT TYPE=\"radio\" NAME=\"chart\" VALUE=\"pie\"" + pieChecked
+ "> Pie Chart");
out.println("<INPUT TYPE=\"radio\" NAME=\"chart\" VALUE=\"bar\"" + barChecked
+ "> Bar Chart");
out.println("<INPUT TYPE=\"radio\" NAME=\"chart\" VALUE=\"time\"" + timeChecked
+ "> Time Series Chart");
out.println("<P>");
out.println("<INPUT TYPE=\"submit\" VALUE=\"Generate Chart\">");
out.println("</FORM>");
out.println("<P>");
out.println("<IMG SRC=\"ServletDemo2ChartGenerator?type=" + param
+ "\" BORDER=1 WIDTH=400 HEIGHT=300/>");
out.println("</BODY>");
out.println("</HTML>");
out.flush();
out.close();
}
catch (Exception e) {
System.err.println(e.toString());
}
finally {
out.close();
}
}
}
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