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- import javax.servlet.ServletConfig;
- 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 com.google.gson.Gson;
- import java.util.*;
- import java.io.*;
- import java.sql.*;
- /**
- * Servlet implementation class sensorToDB
- */
- @WebServlet("/SensorServerDB")
- public class sensorServerDB extends HttpServlet {
- private static final long serialVersionUID = 1L;
- Gson gson = new Gson();
- Connection conn = null;
- Statement stmt;
- public void init(ServletConfig config) throws ServletException {
- // init method is run once at the start of the servlet loading
- // This will load the driver and establish a connection
- super.init(config);
- String user = "maliki";
- String password = "hansderG4";
- // Note none default port used, 6306 not 3306
- String url = "jdbc:mysql://mudfoot.doc.stu.mmu.ac.uk:6306/"+user;
- // Load the database driver
- try { Class.forName("com.mysql.jdbc.Driver").newInstance();
- } catch (Exception e) {
- System.out.println(e);
- }
- // get a connection with the user/pass
- try {
- conn = DriverManager.getConnection(url, user, password);
- System.out.println("Sensor to DB server is up and running\n");
- System.out.println("Upload sensor data with http://localhost:8080/MDAssignment-server/sensorServerDB?sensorData=some_sensor_data_in_json_format");
- System.out.println("View last sensor reading at http://localhost:8080/MDAssignment-server/sensorServerDB?getdata=true\n\n");
- // System.out.println("DEBUG: Connection to database successful.");
- stmt = conn.createStatement();
- } catch (SQLException se) {
- System.out.println(se);
- System.out.println("\nDid you alter the lines to set user/password in the sensor server code?");
- }
- } // init()
- public void destroy() {
- try { conn.close(); } catch (SQLException se) {
- System.out.println(se);
- }
- } // destroy()
- public sensorServerDB() {
- super();
- // TODO Auto-generated constructor stub
- }
- protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
- response.setStatus(HttpServletResponse.SC_OK);
- // Declare a SensorData object to hold the incoming data
- sensorData oneSensor = new sensorData("unknown", "unknown", "unknown");
- // Check to see whether the client is requesting data or sending it
- String getdata = request.getParameter("getdata");
- // if no getdata parameter, client is sending data
- if (getdata == null){
- // getdata is null, therefore it is receiving data
- // Extract the parameter data holding the sensordata
- String sensorJsonString = request.getParameter("sensordata");
- // Problem if sensordata parameter not sent, or is invalid json
- if (sensorJsonString != null) {
- // Convert the json string to an object of type SensorData
- oneSensor = gson.fromJson(sensorJsonString, sensorData.class);
- // now update the table
- updateSensorTable(oneSensor);
- } // endif sensorJsonString not null
- } // end if getdata is null
- else { // Retrieve and return data (JSON format)
- // Code to retrieve data
- String sensorName = request.getParameter("sensorname");
- String resultsJson = retrieveSensorData(sensorName);
- // Update sensor values and send back response
- PrintWriter out = response.getWriter();
- out.println(resultsJson);
- out.close();
- }
- }
- protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
- // Post is same as Get, so pass on parameters and do same
- doGet(request, response);
- }
- private void updateSensorTable(sensorData oneSensor){
- try {
- // Create the INSERT statement from the parameters
- // set time inserted to be the current time on database server
- String updateSQL =
- "insert into sensorusage(userid, sensorname, sensorvalue) " +
- "values('"+oneSensor.getUserid() + "','" +
- oneSensor.getName() + "','" +
- oneSensor.getVlaue() + "'," +
- "now());";
- System.out.println("DEBUG: Update: " + updateSQL);
- stmt.executeUpdate(updateSQL);
- System.out.println("DEBUG: Update successful ");
- } catch (SQLException se) {
- // Problem with update, return failure message
- System.out.println(se);
- System.out.println("\nDEBUG: Update error - see error trace above for help. ");
- return;
- }
- // all ok, return
- return;
- }
- private String retrieveSensorData(String sensorname) {
- String selectSQL = "select * from sensorusage where sensorname='" +
- sensorname + "' order by timeinserted asc";
- ResultSet rs;
- // Declare ArrayList of sensors to hold results
- ArrayList<sensorData> allSensors = new ArrayList<sensorData>();
- try {
- // create a result set of selected values
- rs = stmt.executeQuery(selectSQL);
- // Declare a SensorData object to hold individual values,
- // initialise to defaults
- sensorData oneSensor = new sensorData("unknown", "unknown", "unknown"); // fill in statement
- // iterate over the result set
- while (rs.next()) {
- oneSensor.setName(rs.getString("sensorname"));
- oneSensor.setValue(rs.getString("sensorvalue"));
- oneSensor.setUserid(rs.getString("userid"));
- oneSensor.setName(rs.getString("sensorname"));
- //oneSensor.setSensordate(rs.getString("timeinserted"));
- // add this sensor to ArrayList of Sensors
- allSensors.add(oneSensor);
- // debug print this sensor to console
- System.out.println(oneSensor.toString());
- }
- } catch (SQLException ex) {
- System.out.println("Error in SQL " + ex.getMessage());
- }
- // Convert sensor list to json array and send back to user
- String allSensorsJson = gson.toJson(allSensors);
- // return this String from method
- return allSensorsJson;
- }
- }
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