Java tutorial
/* * To change this license header, choose License Headers in Project Properties. * To change this template file, choose Tools | Templates * and open the template in the editor. */ package org.SRV; import com.google.gson.Gson; import com.journaldev.spring.model.Essence; import java.io.IOException; import java.io.PrintWriter; import java.util.Date; import java.util.List; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; import javax.persistence.Query; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.json.JSONObject; import org.springframework.security.core.context.SecurityContextHolder; import org.springframework.security.core.userdetails.UserDetails; /** * * @author Abbas */ @WebServlet(name = "testServlet", urlPatterns = { "/testServlet" }) public class testServlet extends HttpServlet { /** * Processes requests for both HTTP <code>GET</code> and <code>POST</code> * methods. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=UTF-8"); PrintWriter out = response.getWriter(); try { /* TODO output your page here. You may use following sample code. */ out.println("<!DOCTYPE html>"); out.println("<html>"); out.println("<head>"); out.println("<title>Servlet testServlet</title>"); out.println("</head>"); out.println("<body>"); out.println("<h1>Servlet testServlet at " + request.getContextPath() + "</h1>"); out.println("</body>"); out.println("</html>"); } finally { out.close(); } } // <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 { entityManagerFactory = Persistence.createEntityManagerFactory("org.SRV_war_1.0.0-BUILD-SNAPSHOTPU"); EntityManager entityManager = entityManagerFactory.createEntityManager(); // List<Essence> essence = entityManager.createQuery("select * from essence").getResultList(); //Query query = entityManager.createQuery("FROM Essence u WHERE u.id = :id").setParameter("id", 1); //List<Essence> resultList = query.getResultList(); List<Essence> resultList = entityManager.createQuery("SELECT e FROM Essence e").getResultList(); entityManager.close(); entityManagerFactory.close(); String json = new Gson().toJson(resultList); response.getWriter().write(json); } /** * 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 */ EntityManagerFactory entityManagerFactory; @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { double value1 = Double.parseDouble(request.getParameter("val1")); double value2 = Double.parseDouble(request.getParameter("val2")); UserDetails user = (UserDetails) SecurityContextHolder.getContext().getAuthentication().getPrincipal(); String username = user.getUsername(); //com.seostella_springsecuritybasics_war_1.0.0-BUILD-SNAPSHOTPU entityManagerFactory = Persistence.createEntityManagerFactory("org.SRV_war_1.0.0-BUILD-SNAPSHOTPU"); double result = 0; switch (request.getParameter("operation").charAt(0)) { case '+': result = value1 + value2; break; case '-': result = value1 - value2; break; case '*': result = value1 * value2; break; case '/': result = value1 / value2; break; default: break; } EntityManager entityManager = entityManagerFactory.createEntityManager(); entityManager.getTransaction().begin(); Date date = new Date(); Essence essence = new Essence(); essence.setLogin(username); essence.setDate(date); essence.setValue1(Double.toString(value1)); essence.setValue2(Double.toString(value2)); essence.setOperation(request.getParameter("operation")); essence.setResult(Double.toString(result)); entityManager.persist(essence); entityManager.getTransaction().commit(); entityManager.clear(); entityManager.close(); entityManagerFactory.close(); JSONObject obj; obj = new JSONObject(); obj.put("result", result); //response.getOutputStream().print(obj.toString()); response.getWriter().write(obj.toString()); } /** * Returns a short description of the servlet. * * @return a String containing servlet description */ @Override public String getServletInfo() { return "Short description"; }// </editor-fold> }