LearnInJava/IntroducingJavaEE7Sources/src/java/org/javaee7/chapter01/WriterExample.java at master · ArianZhang/LearnInJava · GitHub

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package org.javaee7.chapter01;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 *
 * @author Juneau
 */
@WebServlet(name = "WriterExample", urlPatterns = {"/WriterExample"})
public class WriterExample extends HttpServlet {

    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        String filename = "/WEB-INF/test.txt";
        ServletContext context = getServletContext();

        InputStream in = context.getResourceAsStream(filename);
        try (PrintWriter out = response.getWriter()) {
            String path = "http://"
                    + request.getServerName()
                    + ":"
                    + request.getServerPort()
                    + request.getContextPath()
                    + "/WriteListenerServlet";
            out.println("<html>");
            out.println("<head>");
            out.println("<title>Intro to Java EE 7 - Servlet Writer Example</title>");
            out.println("</head>");
            out.println("<body>");
            out.println("<h1>Servlet WriterExample at " + request.getContextPath() + "</h1>");
            out.println("Invoking the endpoint: " + path + "<br>");
            out.flush();
            URL url = new URL(path);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setChunkedStreamingMode(2);
            conn.setDoOutput(true);
            conn.connect();
            if (in != null) {
                InputStreamReader inreader = new InputStreamReader(in);
                BufferedReader reader = new BufferedReader(inreader);
                String text = "";
                out.println("Beginning Read of Text File...this will be written to another file");
                try (BufferedWriter output = new BufferedWriter(new OutputStreamWriter(conn.getOutputStream()))) {
                    out.println("got the output...beginning loop");
                    while ((text = reader.readLine()) != null) {
                        out.println("reading text");
                        output.write(text);
                        output.flush();

                        Thread.sleep(1000);
                    }
                    output.close();
                }
            }
            out.println("Check GlassFish server.log");
            out.println("</body>");
            out.println("</html>");
        } catch (InterruptedException | IOException ex) {
            Logger.getLogger(ReaderExample.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /**
     * Handles the HTTP
     * <code>GET</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Handles the HTTP
     * <code>POST</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Returns a short description of the servlet.
     *
     * @return a String containing servlet description
     */
    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>
}