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 CPD4414Assign3; import java.io.IOException; import java.io.PrintWriter; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.LinkedHashMap; import java.util.Map; import java.util.Set; import java.util.logging.Level; import java.util.logging.Logger; import javax.servlet.RequestDispatcher; 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.simple.JSONArray; import org.json.simple.JSONObject; /** * * @author Amanda Cohoon - c0628569 */ @WebServlet("/products") public class ProductServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException { try (PrintWriter out = response.getWriter()) { Connection conn = getConnection(); Statement stmt = conn.createStatement(); if (!request.getParameterNames().hasMoreElements()) { out.println(getResults("SELECT * FROM product")); } else { if (request.getParameter("productID") == null) { out.println(getResults("SELECT * FROM product ORDER BY productID DESC LIMIT 1")); } else { int id = Integer.parseInt(request.getParameter("productID")); out.println(getResults("SELECT * FROM product WHERE productID = ?", String.valueOf(id))); } } } catch (SQLException ex) { Logger.getLogger(ProductServlet.class.getName()).log(Level.SEVERE, null, ex); } } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { Set<String> keySet = request.getParameterMap().keySet(); try (PrintWriter out = response.getWriter()) { Connection conn = getConnection(); if (keySet.contains("name") && keySet.contains("description") && keySet.contains("quantity")) { PreparedStatement pstmt = conn .prepareStatement("INSERT INTO `product`(`productID`, `name`, `description`, `quantity`) " + "VALUES (" + "null, '" + request.getParameter("name") + "', '" + request.getParameter("description") + "', " + request.getParameter("quantity") + ");"); try { pstmt.executeUpdate(); request.setAttribute("productID", 2); request.getParameter("productID"); doGet(request, response); //shows updated row } catch (SQLException ex) { Logger.getLogger(ProductServlet.class.getName()).log(Level.SEVERE, null, ex); out.println("Error with inserting values."); response.setStatus(500); } } else { out.println("Error: Not enough data to input"); response.setStatus(500); } } catch (SQLException ex) { Logger.getLogger(ProductServlet.class.getName()).log(Level.SEVERE, null, ex); } } protected void doPut(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { Set<String> keySet = request.getParameterMap().keySet(); try (PrintWriter out = response.getWriter()) { Connection conn = getConnection(); if (keySet.contains("productID") && keySet.contains("name") && keySet.contains("description") && keySet.contains("quantity")) { PreparedStatement pstmt = conn.prepareStatement("UPDATE `product` SET `name`='" + request.getParameter("name") + "',`description`='" + request.getParameter("description") + "',`quantity`=" + request.getParameter("quantity") + " WHERE `productID`=" + request.getParameter("productID")); try { pstmt.executeUpdate(); doGet(request, response); //shows updated row } catch (SQLException ex) { Logger.getLogger(ProductServlet.class.getName()).log(Level.SEVERE, null, ex); out.println("Error updating values."); response.setStatus(500); } } else { out.println("Error: Not enough data to update"); response.setStatus(500); } } catch (SQLException ex) { Logger.getLogger(ProductServlet.class.getName()).log(Level.SEVERE, null, ex); } } protected void doDelete(HttpServletRequest request, HttpServletResponse response) throws IOException { Set<String> keySet = request.getParameterMap().keySet(); try (PrintWriter out = response.getWriter()) { Connection conn = getConnection(); if (keySet.contains("productID")) { PreparedStatement pstmt = conn.prepareStatement( "DELETE FROM `product` WHERE `productID`=" + request.getParameter("productID")); try { pstmt.executeUpdate(); } catch (SQLException ex) { Logger.getLogger(ProductServlet.class.getName()).log(Level.SEVERE, null, ex); out.println("Error deleting entry."); response.setStatus(500); } } else { out.println("Error: Not enough data to delete"); response.setStatus(500); } } catch (SQLException ex) { Logger.getLogger(ProductServlet.class.getName()).log(Level.SEVERE, null, ex); } } private String getResults(String query, String... params) { StringBuilder results = new StringBuilder(); String result = "a"; try (Connection conn = getConnection()) { PreparedStatement pstmt = conn.prepareStatement(query); for (int i = 1; i <= params.length; i++) { pstmt.setString(i, params[i - 1]); } ResultSet rs = pstmt.executeQuery(); JSONObject resultObj = new JSONObject(); JSONArray productArr = new JSONArray(); while (rs.next()) { Map productMap = new LinkedHashMap(); productMap.put("productID", rs.getInt("productID")); productMap.put("name", rs.getString("name")); productMap.put("description", rs.getString("description")); productMap.put("quantity", rs.getInt("quantity")); productArr.add(productMap); } resultObj.put("product", productArr); result = resultObj.toString(); } catch (SQLException ex) { Logger.getLogger(ProductServlet.class.getName()).log(Level.SEVERE, null, ex); } return result; } private Connection getConnection() throws SQLException { Connection conn = null; try { Class.forName("com.mysql.jdbc.Driver"); String jdbc = "jdbc:mysql://localhost/CPD4414"; conn = DriverManager.getConnection(jdbc, "root", ""); } catch (ClassNotFoundException ex) { Logger.getLogger(ProductServlet.class.getName()).log(Level.SEVERE, null, ex); } return conn; } }