I am developing a web project with HSQLDB persistence. My database instance is on server mode, therefore, I need to run a cmd script/ Java method to access my schema.
Tomcat is the container I use to drop my war on port 8080. Gradle is my build system.
Currently I am using the following main method before I deploy my app to properly access my database on runtime:
public static void main(String[] args) throws IOException, ServerAcl.AclFormatException {
final String URL = "file:~/db/cursago";
String user = "user";
String password = "password";
HsqlProperties p = new HsqlProperties();
p.setProperty("server.database.0",URL+";user="+user+";password="+password);
p.setProperty("server.dbname.0","cursago");
Server server = new Server();
server.setProperties(p);
server.setLogWriter(null);
server.setErrWriter(null);
server.start();
System.out.println("Database is running with path: " + URL);
System.out.println("Username: " + user+", Password: " + password);
}
I would like to know if there's a way of making Tomcat/Gradle/IntelliJ IDEA run this main method before a project deploy, instead of running this script by hand.
from here:
you could run the content of your main in the onApplicationEvent like:
public class ApplicationListenerBean implements ApplicationListener<ContextRefreshedEvent> {
#Override
public void onApplicationEvent(ContextRefreshedEvent event) {
final String URL = "file:~/db/cursago";
String user = "user";
String password = "password";
HsqlProperties p = new HsqlProperties();
p.setProperty("server.database.0",URL+";user="+user+";password="+password);
p.setProperty("server.dbname.0","cursago");
Server server = new Server();
server.setProperties(p);
server.setLogWriter(null);
server.setErrWriter(null);
server.start();
System.out.println("Database is running with path: " + URL);
System.out.println("Username: " + user+", Password: " + password);
}
}
This will trigger on every event, that could be application started or redeployed and happens before your application handles requests.
You also can wire in your properties.
There are some difficulties if the server is already running and it can't run in this scope only.
Related
I'm using the DataSourceFactory of dropwizard and H2 to create an in-memory db for testing. Here is what I have
private static final String DBNAME = String.format("JDBITest-%d", System.currentTimeMillis());
protected final DataSourceFactory config = new DataSourceFactory();
{
final String url = String.format("jdbc:h2:mem:%s;", DBNAME) +
"MODE=MySQL;" +
"TRACE_LEVEL_FILE=3;" +
"DB_CLOSE_DELAY=-1;" +
"IGNORECASE=TRUE";
System.out.println("Creating in memory H2 using " + url);
BootstrapLogging.bootstrap();
config.setUrl(url);
config.setUser("sa");
config.setDriverClass("org.h2.Driver");
config.setValidationQuery("SELECT 1");
}
#Before
public void setUp() throws Exception {
Server server = Server.createTcpServer().start(); // (4)
System.out.println("Server started and connection is open.");
System.out.println("URL: jdbc:h2:" + server.getURL() + "/mem:" + DBNAME);
}
When this runs I see
Creating in memory H2 using jdbc:h2:mem:JDBITest-1541641621470;MODE=MySQL;TRACE_LEVEL_FILE=3;DB_CLOSE_DELAY=-1;IGNORECASE=TRUE
Server started and connection is open.
URL: jdbc:h2:tcp://0.0.17.56:9092/mem:JDBITest-1541641621470
Why is the TCP 0.0.17.56? I cannot access this nor can I use the H2.jar to access the shell.
There are several wrong things here.
H2 has different connections modes. In your example you configure DataSourceFactory for in memory connection, but then in #Before method you create new instance of H2 with tcp based connection. More about connection modes here.
So now you have basically 2 instances of H2, in memory and tcp and they are completely unrelated. So you probably need to have only 1 connection type configured for you tests.
If you want to connect to your H2 db outside of JVM (from browser for example) - then you need to have tcp-based connection.
To be able to connect to db from browser you also need to run console application. Which should be inside h2.jar with command like that java -jar h2*.jar. More about this here.
And finally, this peace of code should suitable for you (with in-memory connection):
private static final String DBNAME = String.format("JDBITest-%d", System.currentTimeMillis());
private ManagedDataSource dataSource;
#Before
public void setUp() {
System.out.println("Server started and connection is open.");
final String url = String.format("jdbc:h2:mem:%s;", DBNAME) +
"MODE=MySQL;" +
"TRACE_LEVEL_FILE=3;" +
"DB_CLOSE_DELAY=-1;" +
"IGNORECASE=TRUE";
System.out.println("Creating in memory H2 using " + url);
DataSourceFactory config = new DataSourceFactory();
BootstrapLogging.bootstrap();
config.setUrl(url);
config.setUser("sa");
config.setDriverClass("org.h2.Driver");
config.setValidationQuery("SELECT 1");
dataSource = config.build(null, "test");
}
#Test
public void test() throws SQLException {
Connection connection = dataSource.getConnection();
connection.createStatement().executeUpdate("CREATE TABLE TEST (`id` INT)");
connection.createStatement().executeUpdate("INSERT INTO TEST (`id`) VALUES (1)");
ResultSet resultSet1 = connection.createStatement().executeQuery("SELECT * FROM TEST WHERE `id` = 1");
resultSet1.next();
resultSet1.getInt(1);
System.out.println("Found ID: " + resultSet1.getInt(1));
}
Out:
Server started and connection is open.
Creating in memory H2 using jdbc:h2:mem:JDBITest-1541649996267;MODE=MySQL;TRACE_LEVEL_FILE=3;DB_CLOSE_DELAY=-1;IGNORECASE=TRUE
Found ID: 1
I am building a simple web service in Java using Jersey to add and delete users from a DB.
Where is the best way to do the preprocessing for this, e.g. if i want to establish a connection with the DB?
#Path("/user/service")
public class UserService
{
private Connection connect = null;
final private String host = "localhost";
final private String user = "qwerty";
final private String passwd = "mysql";
final private String database = "user_db";
public void connectToDB() throws Exception
{
Class.forName("com.mysql.jdbc.Driver");
connect = DriverManager.getConnection("jdbc:mysql://" + host + "/"
+ database + "?" + "user=" + user + "&password=" + passwd);
}
#PUT
#Path("/create")
public void createUser(){
System.out.println("Inside Create User method");
}
#GET
#Path("/get/{id}")
public String getUser(#PathParam("id")String userid, #QueryParam("first")String first){
System.out.println("GET: " + first);
}
}
I want to call connectToDB() once at the start and not inside every request.
Thanks
You can create singleton class and move your connectToDB logic into that singleton class and when invoked that singleton class will make a DB connection which can be used in all subsequent calls from the API.
You can also create a connection inside a static block but that's not a clean way imo.
More on singleton
I am trying to create an Akka HTTP server, which will support SSL.
I am aware of this question for scala Akka HTTP 2.0 to use SSL (HTTPS) and I am trying to work it into Java code but I am getting lost.
The DSL akka.http.javadsl.Http class is different for Java and requires akka.actor.ExtendedActorSystem, when I try to create an instance for it I am required to create an application configuration with the com.typesafe.config.Config class, which I can't figure out how to instantiate and what to put in it.
Is there any simpler way? Or any classes I can use to create all the required configurations?
This is a snippet of the code:
// boot up server using the route as defined below
final ActorSystem system = ActorSystem.create();
final ActorMaterializer materializer = ActorMaterializer.create(system);
// Run the server bound to the local machine IP
String hostAddress = InetAddress.getLocalHost().getHostAddress();
// No implementation here?????
Config applicationConfig = new Config() {
}
ExtendedActorSystem extendedActorSystem = new ActorSystemImpl("HttpProxy", applicationConfig, ClassLoader.getSystemClassLoader(), Option.empty());
// todo: missing handler, settings, httpsContext and log
Flow<HttpRequest, HttpResponse, ?> handler;
ServerSettings settings;
akka.japi.Option<HttpsContext> httpsContext;
LoggingAdapter log;
new Http(extendedActorSystem).bindAndHandle(handler, hostAddress, PORT, settings, httpsContext, log, materializer);
System.out.println("Starting server on " + hostAddress + ":" + PORT);
// The server would stop if carriage return is entered in the system cosole
System.out.println("Type RETURN to exit");
System.in.read();
system.shutdown();
It supposed to be something like this:
// boot up server using the route as defined below
// Run the server bound to the local machine IP
String hostAddress = InetAddress.getLocalHost().getHostAddress();
// No implementation here?????
Config applicationConfig = ConfigFactory.load();
ActorSystem system = ActorSystem.create("HttpProxy", applicationConfig);
final ActorMaterializer materializer = ActorMaterializer.create(system);
// todo: missing handler, settings, httpsContext and log
Flow<HttpRequest, HttpResponse, ?> handler;
ServerSettings settings;
akka.japi.Option<HttpsContext> httpsContext;
LoggingAdapter log;
Http.get(system).bindAndHandle(handler, hostAddress, 9000, settings, httpsContext, log, materializer);
System.out.println("Starting server on " + hostAddress + ":" + 9000);
I'm try to set up a simple RMI implementation, but I'm having some trouble.
The server starts up fine, but the client can never seem to find the remote object (Naming.lookup fails every time). From reading around people have mentioned storing the remote object (Bank) in a static variable, but that hasn't worked either.
UPDATE: If I remove all references to the port number, the whole thing seems to work fine. Does anyone know why that is?
Server:
public class Bank extends UnicastRemoteObject implements BankInterface {
public static void main(String args[]) throws Exception {
try{
System.setSecurityManager(new SecurityManager());
System.out.println("Security Manager set.");
Bank myBank = new Bank(Integer.parseInt(args[0]));
System.out.println("Bank instance created");
Naming.rebind("Bank", myBank);
System.out.println("Name rebind completed.");
System.out.println("Server ready for requests!");
}catch(Exception e){
System.out.println("Error in main - " + e.toString());
}
}
}
Client
public class ATM {
public static void main (String args[]) throws Exception {
String URL = "//" + args[0] + ":" + args[1] + "/Bank";
System.out.println("Connecting to: " + URL);
BankInterface bank = (BankInterface)Naming.lookup(URL);
System.out.println("Connected!");
}
}
Stacktrace
Exception in thread "main" java.rmi.NoSuchObjectException: no such object in tab
le
at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(Stream
RemoteCall.java:276)
at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:
253)
at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:379)
at sun.rmi.registry.RegistryImpl_Stub.lookup(Unknown Source)
at java.rmi.Naming.lookup(Naming.java:101)
at ATM.main(ATM.java:8)
Commands I'm running from cmd.exe are:
rmiregistry
java Bank 7777
java ATM localhost 7777 testMethod
You're running the Registry on its default port, and binding to that Registry, by not using a port number in the bind string, but you're looking up a non-existent Registry on port 7777. The bind string and the lookup string should be the same.
NB lookup isn't the same as connecting. There is no connection to your remote object until you call one of its remote methods.
after reading the H2 documentation, I wrote this simple application to create a H2 database in a local directory:
public static void main(String[] args) throws SQLException {
String path = "C:/Temp/H2/";
File fpath = new File(path);
fpath.mkdirs();
FileUtils.recursiveDelete(fpath);
String dbName = "tata";
String connection = "jdbc:h2:file:" + path + dbName;
Server server = Server.createTcpServer(connection);
server.start();
server.stop();
}
This program runs fine, but when I check in the target directory, the database is not there... (i am using release 1.3.161)
You need to actually access the database, files are created lazily:
server.start();
DriverManager.getConnection(connection);
server.stop();
Added line in the middle creates tata.h2.db file where expected (tested with 1.3.155).