Login-Snippet

package Servlet; import Bean.User; import java.io.IOException; import java.io.PrintWriter; import java.sql.Connection; import java.sql.ResultSet; import java.sql.Statement; import java.util.ArrayList; import javax.naming.Context; import javax.naming.InitialContext; import javax.servlet.RequestDispatcher; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import javax.sql.DataSource; /** * * @author libralavender */ public class LoginServlet 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(); // Connection Pool Connection conn = null; try{ InitialContext initialContext = new InitialContext(); Context ctx = (Context)initialContext.lookup("java:comp/env"); DataSource ds = (DataSource)ctx.lookup("mypool"); conn = ds.getConnection(); }catch(Exception e){ System.out.println(); } String username = request.getParameter("username"); String password = request.getParameter("password"); int uid = 0; // Set Session HttpSession session = request.getSession(); User user = new User(); Statement st= null; ResultSet rs= null; Boolean valid = false; try{ st = conn.createStatement(); String query = "select * from users where username ='"+username+"' and password = '"+password+"'"; rs = st.executeQuery(query); //User user = new User(); if(rs.next()){ uid = rs.getInt(8); user.setUid(uid); user.setUsername(rs.getString(1)); user.setPosts(rs.getInt(5)); user.setFollowing(rs.getInt(5)); user.setFollower(rs.getInt(6)); user.setImg(rs.getString(7)); valid = true; } session.setAttribute("user", user); /* search following */ query = "select followingid,username, img,article,articleid from follow,users,posts where follow.uid ="+uid+"and followingid = users.uid and followingid = posterid"; rs = st.executeQuery(query); ArrayList<User> friendlist = new ArrayList<User>(); while(rs.next()){ User friend = new User(); friend.setUid(rs.getInt(1)); friend.setUsername(rs.getString(2)); friend.setImg(rs.getString(3)); friend.setArticle(rs.getString(4)); friend.setArticleid(rs.getInt(5)); friendlist.add(friend); } session.setAttribute("friendlist", friendlist); rs.close(); st.close(); conn.close(); }catch(Exception e){ System.out.print("Cannot execute query"); } if(valid){ RequestDispatcher view = request.getRequestDispatcher("main.jsp"); view.forward(request, response); }else{ try { out.println("<!DOCTYPE html>"); out.println("<html>"); out.println("<head>"); out.println("<title>Servlet LoginServlet</title>"); out.println("</head>"); out.println("<body>"); out.println("<h1>Servlet LoginServlet at"+valid+"</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 { 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> }

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