SHOW:
|
|
- or go back to the newest paste.
| 1 | package com.versefeed.crud; | |
| 2 | ||
| 3 | import java.io.IOException; | |
| 4 | import java.util.List; | |
| 5 | ||
| 6 | import javax.servlet.http.HttpServlet; | |
| 7 | import javax.servlet.http.HttpServletRequest; | |
| 8 | import javax.servlet.http.HttpServletResponse; | |
| 9 | import javax.swing.text.Utilities; | |
| 10 | ||
| 11 | import com.google.appengine.api.datastore.DatastoreService; | |
| 12 | import com.google.appengine.api.datastore.DatastoreServiceFactory; | |
| 13 | import com.google.appengine.api.datastore.Entity; | |
| 14 | import com.google.appengine.api.datastore.Text; | |
| 15 | ||
| 16 | /* | |
| 17 | i declare and instantiate class variable "private CrudDsUtilities utilities" in the servlet constructor, but it's not seen in other functions of the servlet. it is throwing java.lang.NullPointerException | |
| 18 | ||
| 19 | */ | |
| 20 | ||
| 21 | public class CrudServlet extends HttpServlet {
| |
| 22 | ||
| 23 | private DatastoreService ds; | |
| 24 | private String entityKind; | |
| 25 | private CrudDsUtilities utilities; | |
| 26 | ||
| 27 | private void CrudServlet() {
| |
| 28 | ds = DatastoreServiceFactory.getDatastoreService(); | |
| 29 | utilities = new CrudDsUtilities(); | |
| 30 | ||
| 31 | } | |
| 32 | ||
| 33 | public void doGet(HttpServletRequest req, HttpServletResponse resp) | |
| 34 | throws IOException {
| |
| 35 | ||
| 36 | String operation = req.getParameter("op");
| |
| 37 | String verseTitle, verseRef, verseBody; | |
| 38 | long verseId; | |
| 39 | switch (operation) {
| |
| 40 | ||
| 41 | case "view": | |
| 42 | verseId = Long.getLong(req.getParameter("verseId"));
| |
| 43 | entityKind = req.getParameter("entityKind");
| |
| 44 | ||
| 45 | break; | |
| 46 | ||
| 47 | case "viewverses": | |
| 48 | entityKind = req.getParameter("entitykind");
| |
| 49 | System.out.println("entityKind: "+ entityKind);
| |
| 50 | this.viewVerses(req, resp); | |
| 51 | break; | |
| 52 | ||
| 53 | default: | |
| 54 | break; | |
| 55 | } | |
| 56 | ||
| 57 | } | |
| 58 | ||
| 59 | public void viewVerse(long verseId) {
| |
| 60 | ||
| 61 | } | |
| 62 | ||
| 63 | public void viewVerses(HttpServletRequest req, HttpServletResponse resp) {
| |
| 64 | ||
| 65 | //throwing java.lang.NullPointerException on this line! it doesn't see "utilities" as already instantiated in the constructor. | |
| 66 | List<Entity> verses = utilities.getEntitiesAsList(entityKind); | |
| 67 | ||
| 68 | try {
| |
| 69 | // Set the attribute and Forward to hello.jsp | |
| 70 | req.setAttribute ("verses", verses); // to save your temporary calculations.
| |
| 71 | req.getRequestDispatcher("/verses.jsp").forward(req, resp);
| |
| 72 | } catch (Exception ex) {
| |
| 73 | ex.printStackTrace (); | |
| 74 | } | |
| 75 | ||
| 76 | } | |
| 77 | ||
| 78 | }// close class | |
| 79 | ||
| 80 | //traceback | |
| 81 | ||
| 82 | java.lang.NullPointerException | |
| 83 | at com.versefeed.crud.CrudServlet.viewVerses(CrudServlet.java:109) | |
| 84 | at com.versefeed.crud.CrudServlet.doGet(CrudServlet.java:68) | |
| 85 | at javax.servlet.http.HttpServlet.service(HttpServlet.java:617) | |
| 86 | at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) |
