this is the problem once i try to save data into db with sql statement insert.
my function is this:
public void save(){
JPA.em().persist(this);
}
and
public static Result registered() {
Form<User> requestform = form(User.class).bindFromRequest();
if(requestform.hasErrors()){
return badRequest("<p>fehlerhafte eingabe!</p>").as("text/html");
} else {
User user = requestform.get();
String fullname = user.fullname;
String email = user.email;
String password = user.password;
String username = user.username;
new User(username, password, fullname, email).save();
}
return redirect(controllers.routes.Application.index());
}
thanks for help
It is just like the debugging message says, you do not have an entity manager bound to your methods because they are not marked as transactions.
#play.db.jpa.Transactional
public static Result registered() {
Also, if you are using EBean, you could just extend Model for your User class, which comes with many handy built in functions for database use, see documentation here: http://www.playframework.org/documentation/2.0.1/JavaEbean
Related
I'm learning Google App Engine + Google Cloud Endpoints + Objectify and I'm trying to understand how to create REST API which will let each particular user to save his data in the cloud.
My current struggle is how to store Entity owned by the User (com.google.appengine.api.users.User)?
So far I have endpoint:
#ApiMethod(name = "saveBook")
public void saveBook(Book book, User user) throws OAuthRequestException, IOException {
if (user == null) {
throw new OAuthRequestException("User is not authorized");
}
ofy().save()
.entity(BookRecord.fromBook(user, book))
.now();
}
Entity (in this context let's assume that User wrote the book):
#Entity
public class BookRecord {
#Parent
private Key<User> user;
#Id
private String id;
#Index
private String name;
public static BookRecord fromBook(User user, Book book) {
return new BookRecord(
Key.create(user),
book.getId(),
book.getName()
);
}
public BookRecord() {
}
private BookRecord(Key<User> user, String id, String name, String author) {
this.user = user;
this.id = id;
this.name = name;
this.author = author;
}
}
Problem arises from User not being an Entity, so I can't really use this solution and use User as #Parent directly. What is the general solution to solve this problem and store data owned by User?
Create your own User entity, this is where you'll store custom information/preferences for your app (as I suggested here).
You'll be using getUserId() to tie it with the Google user, and from there on you're free to use it as needed.
I am implementing AppEngine server as a backend for my Android application. I use Datastore, I query it via Objectify service and I use Endpoints that I call via URL.
I have an entity User with properties like this:
#Id
Long id;
/**
* Name or nickname of the user
*/
public String name;
#Index
public String email;
#JsonIgnore
List<Key<User>> friends;
public User()
{
devices = new ArrayList<String>();
friendsWithKey = new ArrayList<Key<User>>();
}
public static User findRecordById(Long id)
{
return ofy().load().type(User.class).id(id).now();
}
#ApiMethod(name = "friends", httpMethod = "GET", path = "users/{userId}/friends")
public JSONObject getFriends(#Named("userId") String userId)
{
User user = User.findRecordById(Long.parseLong(userId));
JSONObject friendsObject = new JSONObject();
JSONArray jsonArray = new JSONArray();
JSONObject friend;
List<User> userList = new ArrayList<User>();
if (user.friendsWithKey != null)
{
for (Key<User> id : user.friendsWithKey)
{
friend = new JSONObject();
User user1 = User.findRecordById(id.getId());
userList.add(user1);
friend.put("name", user1.name);
friend.put("email", user1.email);
friend.put("id", user1.id);user1.lastTimeOnline.getTime());
jsonArray.add(friend);
}
friendsObject.put("friends", jsonArray);
}
return friendsObject;
}
It sometimes returns only a subset of friends. It is weird and I do not get where I could go wrong. If I get the User object from the DB, it already has a wrong List of Key values. But if I look into the database via console, I can see all of the users that ahve been added as friends.
I reaally need to fix this bug. Please, help.
It is very strange because it only happens once in a while and is non-deterministic in every way.
I am working on an MVC3 application database first approach . I would like to use one connection string to connect to database, based on some string (company name). Example: I have in my MSSQL Express 2012 this db: my_database_microsoft, my_database_oracle and so on..(those databases have same structure). On login page I have 3 input fields: username,password,company. I know how to build connection string dynamic with SqlConnectionStringBuilder and then use it on EntityConnectionStringBuilder
string providerName = "System.Data.SqlClient";
string serverName = "MY-PC\\SQL2012";
string databaseName = "my_database_"+form[company].toString();
.....
.....
entityBuilder.Provider = providerName;
// Set the provider-specific connection string.
entityBuilder.ProviderConnectionString = providerString;
// Set the Metadata location.
entityBuilder.Metadata =#"res://*/Models.Model1.csdl|res://*/Models.Model1.ssdl|res://*/Models.Model1.msl";
using (EntityConnection conn =
new EntityConnection(entityBuilder.ToString()))
{
conn.Open();
// Console.WriteLine("Just testing the connection.");
conn.Close();
}
obracun_placEntities1.nameOrConnectionString = entityBuilder.ToString();
obracun_placEntities1 o = new obracun_placEntities1(entityBuilder.ToString());
I have made a partial class of my entety and give a constructor that take a nameOrConnectionString string as a parameter.
public partial class obracun_placEntities1
{
public string nameOrConnectionString { get; set; }
public obracun_placEntities1(string nameOrConnectionString)
: base(nameOrConnectionString ?? "obracun_placEntities1") { }
}
This works only in loginController but how can I use this in UsersController and all other controllers where I using obracun_placEntities1 db = new obracun_placEntities1(); > this take the default database from web.config. I would not like to save connection string to session or cookie and than pass it in every controler as a parameter.
private obracun_placEntities1 db = new obracun_placEntities1();
How can i achieve that i pass connection string in login controller and using this database in entire project.
One more problem occured when i want to use public static string nameOrConnectionString
and pass it to constructor. The problem is when I open application in Chrome and login as user1 I get all infromation from user1 database, but then I login in MS Explorere as user2 and get all data from user2 database. When i refresh chrome I get information from the user2 database not user1.
Model1.context.cs
public partial class obracun_placEntities1 : DbContext
{
public static string nameOrConnectionString { get; set; }
// public static string connection;
public obracun_placEntities1()
: base(nameOrConnectionString ?? "obracun_placEntities1")
{
}
Connecting to different Databases is best done using the DBconnection constructor on DBCOntext. If you look at the DBContext class you will see multiple constructor overloads. One allows the DBConnection to be supplied. So no entry in WEB.Config/App.Config is required.
See this post with sample code Same Context accessing different databases.
EDIT sample added:
public partial class obracun_placEntities1 : DbContext
{
// use THIS CONSTRUCTOR
protected obracun_placEntities1(DbConnection dbConnection, bool contextOwnsConnection)
: base(dbConnection, contextOwnsConnection)
{
}
}
}
// DONT USE THIS
// obracun_placEntities1.nameOrConnectionString = entityBuilder.ToString();
// obracun_placEntities1 o = new obracun_placEntities1(entityBuilder.ToString());`
// build the connection - note: it is NOT a connection string. it is a DBConnection!
conn = getDBConnection4SQLServer(DatabaseServer,Databasename)
obracun_placEntities1 o = new obracun_placEntities1(conn,true);
//====================================================================
public const string DefaultDataSource = "localhost";
public DbConnection getDBConnection4SQLServer(string dataSource, string dbName) {
var sqlConnStringBuilder = new SqlConnectionStringBuilder();
sqlConnStringBuilder.DataSource = String.IsNullOrEmpty(dataSource) ? DefaultDataSource : dataSource;
sqlConnStringBuilder.IntegratedSecurity = true;
sqlConnStringBuilder.MultipleActiveResultSets = true;
var sqlConnFact = new SqlConnectionFactory(sqlConnStringBuilder.ConnectionString);
var sqlConn = sqlConnFact.CreateConnection(dbName);
return sqlConn;
}
I finnaly getting it to work with this code.
My LoginController
[HttpPost]
public ActionResult Index(UPORABNIK model, FormCollection form)
{....}
public obracun_placEntities1(EntityConnection entityConnection)
: base(entityConnection, false)
{
}
I call EntityConnection conn = GetEntityConnDbName("ServerName", "FirmName").
_entities = new obracun_placEntities1(conn, false);
var uporabniki = from r in _entities.UPORABNIK.Where(r => r.ime == uporabnik && r.geslo == geslo && danes <= r.veljavnost).ToList()
select r;
I get the firmName from the post form so this work only in LoginController.But how can I use this constructor in all other Controllers? I get firm name only once in LoginControler, I tried to save it as cookie but then i can not read it in the constructor.
In my other Controller I use the default controller again. How can I tranfer conn to other Controllers?
private obracun_placEntities1 db = new obracun_placEntities1();
I would like to call like this
private obracun_placEntities1 db = new obracun_placEntities1(conn);
Or is there some better way?
I am confused to using auto-generated endpoint class. I want to use generated endpoint to insert new object into datastore. But, an exception is throwing.
fooEndpoint.insertFoo(foo); // throws null pointer exception
My entity class is similar with the given example at this source: https://developers.google.com/appengine/docs/java/datastore/jpa/overview.
Here is my entity:
#Entity
public class Foo {
#Id
#GeneratedValue(strategy=GenerationType.IDENTITY)
private Key ID;
Here is the stack trace:
java.lang.NullPointerException
at org.datanucleus.api.jpa.JPAEntityManager.find(JPAEntityManager.java:318)
at org.datanucleus.api.jpa.JPAEntityManager.find(JPAEntityManager.java:256)
at com.FooEndpoint.containsFoo(FooEndpoint.java:150)
at com.FooEndpoint.insertFoo(FooEndpoint.java:96)
On the other side, I can insert new object when I use the EntityManager persist method. Because, this does not check exist or not on the datastore.
I expect that, classEndpoint insert method should save the object and assing auto key to ID field.
Or I need to initialize the ID field.
Here is auto-generated endpoint class insertFoo method.
/**
* This inserts a new entity into App Engine datastore. If the entity already
* exists in the datastore, an exception is thrown.
* It uses HTTP POST method.
*
* #param foo the entity to be inserted.
* #return The inserted entity.
*/
public Foo insertFoo(Foo foo) {
EntityManager mgr = getEntityManager();
try {
if (containsFoo(foo)) {
throw new EntityExistsException("Object already exists");
}
mgr.persist(foo);
} finally {
mgr.close();
}
return foo;
}
Here is the containsFoo method
private boolean containsFoo(Foo foo) {
EntityManager mgr = getEntityManager();
boolean contains = true;
try {
Foo item = mgr.find(Foo.class, foo.getID()); // exception occurs here
if (item == null) {
contains = false;
}
} finally {
mgr.close();
}
return contains;
}
foo.getID() is null. Because, it is new object. I am expecting that, app engine creates a key for it. Or I need to explicitly create a key for it?
Other fields in Foo class are simple types such as String and booleans.
Thanks for your time.
I had exactly the same problem.
I will present the way I worked around it.
Original auto-generated Endpoints class relevant code:
private boolean containsFoo(Foo foo) {
EntityManager mgr = getEntityManager();
boolean contains = true;
try {
Foo item = mgr.find(Foo.class, foo.getID());
if (item == null) {
contains = false;
}
} finally {
mgr.close();
}
return contains;
}
Changed relevant code to include a null check for the entity object that is passed as an argument.
private boolean containsFoo(Foo foo) {
EntityManager mgr = getEntityManager();
boolean contains = true;
try {
// If no ID was set, the entity doesn't exist yet.
if(foo.getID() == null)
return false;
Foo item = mgr.find(Foo.class, foo.getID());
if (item == null) {
contains = false;
}
} finally {
mgr.close();
}
return contains;
}
This way it will work as supposed, although I'm confident that more experienced answers and explanations will appear.
I was having the same exact problem after using the Eclipse Plugin to autogenerate the cloud endpoints (by selecting "Google > Generate Cloud Endpoint Class").
Following your advice, I added:
if(foo.getID() == null) // replace foo with the name of your own object
return false;
The problem was solved.
How is that Google hasn't updated the autogenerated code yet as this must be a highly recurring issue?
Thanks for the solution.
I have a web form where I need to add, update, delete and read using a unique ID. So far I have managed to add, update and delete functions with little trouble.
However now I am having trouble getting my read function to work (understand I have a webform that has four text fields; ID, FIRSTNAME, SURNAME AND ADDRESS). Basically when an ID that has been previously created (using add button) is entered into the text field and the read button clicked it should update the other 3 text fields with the stored entries depending on the ID entered.
Here is my behind code (cs.) on the web form
protected void cmdRead_Click(object sender, EventArgs e)
{
// Create a reference to the Web service
DbWebService.WebService1 proxy = new DbWebService.WebService1();
// Create a person details object to send to the Web service.
string ADDRESS;
string SURNAME;
string FIRSTNAME;
string ID;
ADDRESS = txtAddress.Text;
SURNAME = txtSurname.Text;
FIRSTNAME = txtFirstname.Text;
ID = txtID.Text;
// Attempt to store in the Web service
bool rsp = proxy.ReadPerson(int.Parse(ID), FIRSTNAME, SURNAME, ADDRESS);
// Inform the user
if (rsp)
{
lblOutcome.Text = "Successfully read data.";
txtFirstname.Text = FIRSTNAME;
txtSurname.Text = SURNAME;
txtAddress.Text = ADDRESS;
}
else
{
lblOutcome.Text = "Failed to read data! Select a previously created ID!";
}
}
and here is my web function on the web service (which is where the SQL Server Express database is)
[WebMethod]
public bool ReadPerson(int ID, string FIRSTNAME, string SURNAME, string ADDRESS)
{
// In case of failure failure first
bool rtn = false;
// Connect to the Database
SqlConnection connection = new SqlConnection(#"Data Source=.\SQLEXPRESS;AttachDbFilename='|DataDirectory|\Database.mdf';Integrated Security=True;User Instance=True");
// Open the connection
connection.Open();
// Prepare an SQL Command
SqlCommand command = new SqlCommand(String.Format("SELECT FIRSTNAME, SURNAME, ADDRESS FROM PersonalDetails WHERE ID = '{0}'", ID), connection);
// Execute the SQL command and get a data reader.
SqlDataReader reader = command.ExecuteReader();
// Instruct the reader to read the first record.
if (reader.Read())
{
// A record exists, thus the return value is updated
FIRSTNAME = (string)reader["FIRSTNAME"];
SURNAME = (string)reader["SURNAME"];
ADDRESS = (string)reader["ADDRESS"];
rtn = true;
}
// Close the connection
connection.Close();
// Return the result.
return (rtn);
}
Now the problem is when I click read I get a success message (using a label as you can see in the behind code) but the fields don't update, I assume this is because of the (rtn = true;) statement. Therefore I thought something like this might work:
rtn = (bool)reader["ADDRESS"];
However with this I get a specified cast is not valid, so I figure maybe the bool doesn't work in this context, I think it might work if I use string instead but how do I convert, I think rtn needs a value in regards to the reader right??
Basically I am just looking for a solution to which will update the text fields in the web form.
There are several problems with your code. The most obvious is that your code cannot ever return the data from the database. You are sending FIRSTNAME etc. to the web service - you are not returning them from the web service.
There is no reason to have a bool return from the service to tell you whether or not it succeeded. Let the service throw an exception if it failed. Instead, you should return the fields from the database as the return of the service.
In the service:
public class Person
{
public string FIRSTNAME {get;set;}
public string SURNAME {get;set;}
public string ADDRESS {get;set;}
}
[WebMethod]
public Person ReadPerson(int ID)
{
// ...
if (reader.Read())
{
// A record exists, thus return the value
Person p = new Person();
p.FIRSTNAME = (string)reader["FIRSTNAME"];
p.SURNAME = (string)reader["SURNAME"];
p.ADDRESS = (string)reader["ADDRESS"];
rtn = p;
}
connection.Close();
return rtn;
}
Also, you should not be using a WebMethod or an ASMX web service unless you have no choice. ASMX is a legacy technology which is kept around only for backwards compatability. It should not be used for new development. You should use WCF instead.
The other issues with your code are resolved below:
[WebMethod]
public Person ReadPerson(int id)
{
using (
var connection =
new SqlConnection(
#"Data Source=.\SQLEXPRESS;
AttachDbFilename='|DataDirectory|\Database.mdf';
Integrated Security=True;
User Instance=True")
)
{
connection.Open();
using (
var command =
new SqlCommand(#"
SELECT FIRSTNAME, SURNAME, ADDRESS
FROM PersonalDetails
WHERE ID = #id",
connection))
{
var idParameter =
command.Parameters.Add(
"#id", SqlDbType.Int);
idParameter.Value = id;
using (var reader = command.ExecuteReader())
{
if (!reader.Read())
{
return null;
}
return new Person
{
Firstname =
(string)
reader["FIRSTNAME"],
Surname =
(string)
reader["SURNAME"],
Address =
(string)
reader["ADDRESS"]
};
}
}
}
}
The main issue is that the SqlConnection, SqlCommand, and SqlDataReader all need to be instantiated inside of using blocks. This ensures that the objects are disposed of (closed) whether or not an exception is thrown.
Next, you should not get into the habit of building queries through string manipulation; not even using String.Format. That leaves you open to "SQL Injection" attacks. Using parameters resolves that problem. See "Commands and Parameters " in MSDN.
One last minor issue: I recommend that you get out of the habit of placing comments on obvious statements. For instance, it's not necessary to comment that Open opens the connection to the database, or that return returns a value.