Spring Boot and Spring-starter-data-jpa : Lazy loading of datasource setup - spring

Question

I am working on an application with Spring-starter-data-jpa and multi datasources, that need to lazy initialize datasouce connection, but i dosen't manage to work with it.
For exemple if i put a wrong password on a datasource configuration, the application startup fails.
I try to put a #Lazy annotation on the Datasource #Configuration class but the application still crash on startup.
I try to implement a LazyConnectionDataSourceProxy instead the Datasource without success.
I can't imagine that it is not possible.
Is somewone have an idea to how lazy load datasources configuration on the first jpa repository call ?
I tryed to do this with a kind of adapter/singleton mix pattern like this :
#Component
public class TestErrorDatasource implements DataSource {
private DataSource datasource;
#Autowired Environment env;
#Override
public PrintWriter getLogWriter() throws SQLException {
return getDatasource().getLogWriter();
}
#Override
public int getLoginTimeout() throws SQLException {
return getDatasource().getLoginTimeout();
}
#Override
public Logger getParentLogger() throws SQLFeatureNotSupportedException {
return getDatasource().getParentLogger();
}
#Override
public void setLogWriter(PrintWriter arg0) throws SQLException {
getDatasource().setLogWriter(arg0);
}
#Override
public void setLoginTimeout(int arg0) throws SQLException {
getDatasource().setLoginTimeout(arg0);
}
#Override
public boolean isWrapperFor(Class<?> arg0) throws SQLException {
return getDatasource().isWrapperFor(arg0);
}
#Override
public <T> T unwrap(Class<T> arg0) throws SQLException {
return getDatasource().unwrap(arg0);
}
#Override
public Connection getConnection() throws SQLException {
return getDatasource().getConnection();
}
#Override
public Connection getConnection(String arg0, String arg1) throws SQLException {
return getDatasource().getConnection(arg0, arg1);
}
private DataSource getDatasource() {
if(datasource == null) {
this.datasource = DataSourceBuilder
.create()
.driverClassName(env.getProperty("testError.datasource.driverClassName"))
.url(env.getProperty("testError.datasource.url"))
.username(env.getProperty("testError.datasource.username"))
.password(env.getProperty("testError.datasource.password"))
.build();
}
return datasource;
}
}
But it dosen't work.
I put a break point on the getConnection() methode and i raised tha it's called on startup by
org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl
class
Is there any configuration to avoid hibernate check the getConnection() methode on starup ?
Thanks in advance

Answer 1

A datasource is just an interface with a 'getConnection()' method on it.
So create your own implementation that delegates to a singleton that is created only when getConnection is first called.
In other words, whilst your implementation can be a Spring bean, its singleton dependency isn't, and isn't injected, but set the first time you access getConnection.