Здравствуйте! Я попробовал переделать "студенческий отдел кадров" Антона Сабурова из http://www.java-course.ru/, с реализацией хранилища данных для google app engine... Вроде бы заработало, но не совсем... При сохранении объекта в датастор (google app engine datastore) создается аж по 2-3 копии объекта. Вот пример ManagementSystem со вставкой объекта: | Код |
package students.logic;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Set;
import javax.persistence.EntityManager;
import javax.persistence.EntityTransaction;
import javax.persistence.Query;
import com.google.appengine.api.datastore.Key;
import students.logic.EMF;
import students.entity.Groups;
import students.entity.Students;
public class Students_ManagementSystem {
private static final Students_ManagementSystem ms = new Students_ManagementSystem();
public static Students_ManagementSystem getInstance(){
return ms;
}
public synchronized void insertStudent(Students student){
EntityManager em = EMF.get().createEntityManager();
EntityTransaction tx = em.getTransaction();
tx.begin();
try {
em.persist(student);
tx.commit();
} finally {
if (tx.isActive()) {
tx.rollback();
}
}
em.close();
}
|
вот пример из сервлета: | Код |
package students.logic;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.google.appengine.api.datastore.Key;
import com.google.appengine.api.datastore.KeyFactory;
import students.entity.Groups;
import students.entity.Students;
import students.web.forms.MainFrameForm;
public class Students_Groups_FrameServlet extends HttpServlet {
private Students_ManagementSystem ms = Students_ManagementSystem.getInstance();
private Groups_ManagementSystem msg = Groups_ManagementSystem.getInstance();
private static final SimpleDateFormat sdf = new SimpleDateFormat(
"dd.MM.yyyy");
protected void processRequest(HttpServletRequest req,
HttpServletResponse resp) throws ServletException, IOException {
Long sId = null;
Long gId = null;
if(req.getParameter("studentId")!=null){
if(!req.getParameter("studentId").isEmpty())
sId = Long.parseLong(req.getParameter("studentId"));
}
if(req.getParameter("groupId")!=null){
if(!req.getParameter("groupId").isEmpty())
gId = Long.parseLong(req.getParameter("groupId"));
}
if (gId!=null && sId != null && req.getParameter("OK") != null) {
try {
updateGroups(req);
updateStudent(req);
} catch (SQLException sql_e) {
sql_e.printStackTrace();
throw new IOException(sql_e.getMessage());
} catch (ParseException p_e) {
throw new IOException(p_e.getMessage());
}
}
else {
try {
insertGroups(req);
insertStudent(req);
} catch (SQLException sql_e) {
sql_e.printStackTrace();
throw new IOException(sql_e.getMessage());
} catch (ParseException p_e) {
throw new IOException(p_e.getMessage());
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
Integer ys = Integer.parseInt(req.getParameter("educationYear"));
int year = Calendar.getInstance().get(Calendar.YEAR);
if (ys != null) {
year = ys;
}
MainFrameForm form = new MainFrameForm();
List<Groups> groups = msg.getGroups();
//Students st = new Students();
if (gId == null) {
Iterator<Groups> i = groups.iterator();
gId = i.next().getGroupId();
}
Collection<Students> students = ms.getStudentsFromGroup(gId, year);
form.setGroupId(gId);
form.setYear(year);
form.setGroups(groups);
form.setStudents(students);
req.setAttribute("form", form);
getServletContext().getRequestDispatcher("/MainFrame.jsp").forward(req,
resp);
}
private synchronized void updateStudent(HttpServletRequest req) throws SQLException,
ParseException {
Students st = prepareStudent(req);
Groups gr = prepareGroups(req);
msg.updateGroup(gr);
st.setGroupId(gr.getGroupId());
ms.updateStudent(st);
}
private synchronized void insertStudent(HttpServletRequest req) throws SQLException,
ParseException, InterruptedException {
Students st = prepareStudent(req);
Groups gr = prepareGroups(req);
msg.insertGroup(gr);
Long grId = gr.getGroupId();
st.setGroupId(grId);
ms.insertStudent(st);
}
private Students prepareStudent(HttpServletRequest req)
throws ParseException {
Students s = new Students();
if (req.getParameter("studentId")!=null) {
if(!req.getParameter("studentId").isEmpty()){
s.setStudentId(Long.parseLong(req.getParameter("studentId")));
}
}
if(req.getParameter("groupId")!=null){
if(!req.getParameter("groupId").isEmpty()){
s.setGroupId(Long.parseLong(req.getParameter("groupId")));
}
}
s.setFirstName(req.getParameter("firstName").trim());
s.setSurName(req.getParameter("surName").trim());
s.setPatronymic(req.getParameter("patronymic").trim());
s.setDateOfBirth(sdf.parse(req.getParameter("dateOfBirth").trim()));
if (req.getParameter("sex").equals("0")) {
s.setSex('М');
} else {
s.setSex('Ж');
}
//s.setGroupId(Long.parseLong(req.getParameter("groupId").trim())); //it is null
s.setEducationYear(Integer.parseInt(req.getParameter("educationYear")
.trim()));
return s;
}
private Groups prepareGroups(HttpServletRequest req)
throws ParseException {
Groups gr = new Groups();
if(req.getParameter("groupId")!=null){
if(!req.getParameter("groupId").isEmpty()){
gr.setGroupId(Long.parseLong(req.getParameter("groupId")));
}
}
gr.setCurator(req.getParameter("curator").trim());
gr.setGroupName(req.getParameter("groupName").trim());
gr.setSpeciality(req.getParameter("speciality").trim());
return gr;
}
private synchronized void insertGroups(HttpServletRequest req) throws ParseException{
Groups gr = prepareGroups(req);
msg.insertGroup(gr);
}
private synchronized void updateGroups(HttpServletRequest req) throws ParseException{
Groups gr = prepareGroups(req);
msg.updateGroup(gr);
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
processRequest(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
processRequest(req, resp);
}
}
|
код: http://narod.ru/disk/24138759000/StuffTest.zip.html. хотелось бы понять где я что-то пропускаю... делеал в эклипсе. ссылка на работающее, но недоделанное приложение: http://www.studentstufftest.appspot.com/Это сообщение отредактировал(а) dim9999 - 27.8.2010, 02:51 |
Множественное сохранение сущности в хранилище, не поместилось 
Загрузка ...
