ENV.md

DaoEnv How To

Description

uia.dao.DaoEnv is a abstract class which try to use a simpler way to access database.

DaoEnv provides 5 helper methods to create the DaoEnv object.

• DaoEnv.dataSource - Connection from data source.
• DaoEnv.pool - Connection from connection pool. The implementation uses Hikari.
• DaoEnv.postgre - Simple PostgreSQL JDBC connection.
• DaoEnv.hana - Simple HANA JDBC connection.
• DaoEnv.oracle - Simple Oracle JDBC connection.

All helper methods above have two arguments

• date2UTC - if timestamp needs to be converted to UTC time.
• packageName - The package name of DTO classes.

How To

1. Create a DaoEnv object.

• Data Source

  DaoEnv env = DaoEnv
      .dataSource(false, "your.dto.package")
      .config(connString, user, password, schema);

• Connection Pool

  DaoEnv env = DaoEnv
      .pool(false, "your.dto.package")
      .config(connString, user, password, schema);

• HANA

  DaoEnv env = DaoEnv
      .hana(false, "your.dto.package")
      .config(connString, user, password, schema);

• Oracle

  DaoEnv env = DaoEnv
      .oracle(false, "your.dto.package")
      .config(connString, user, password, schema);

• PostgreSQL

  DaoEnv env = DaoEnv
      .postgre(false, "your.dto.package")
      .config(connString, user, password, schema);

2. Use a session to create a Dao object and select all data.

• Use custom DAO object

  public class MyClassDao extends TableDao<MyClass> {
      ...
  }

  try (DaoSession session = env.createSession()) {
      MyClassDao dao = session.tableDao(MyClassDao.class);
      List<MyClass> result = dao.selectAll();
  }

• Use generic uia.dao.TableDao object

  try (DaoSession session = env.createSession()) {
      TableDao<MyClass> dao = session.forTable(MyClass.class);
      List<MyClass> result = dao.selectAll();
  }

Spring Integration

1. Create a component

The component inherits from uia.dao.DaoEnv and annotate scope to ConfigurableBeanFactory.SCOPE_SINGLETON.

package a.b.c;

@Component("db")
@Scope(ConfigurableBeanFactory.SCOPE_SINGLETON)
public class MyDaoEnv extends DaoEnv {
	
	public MyDaoEnv() throws Exception {
		super(DaoEnv.POSTGRE, false);   // connect to the PostgreSQL
		config(connString, user, password, null);
	}

	@Override
	protected void initialFactory(DaoFactory factory) throws Exception {
		factory.load("your.dto.package");
	}

2. Create a configuration class

package a.b.c;

@Configuration
@ComponentScan
public class DaoEnvConfig {
	
}

3. use @Autowired to get the DaoEnv instance.

@Service
public class MyServiceImpl implements MyService {

	@Autowired
	@Qualifier("db")
	private DaoEnv env; // Component: "db" 
	
	@Override
	public void run() throws Exception {
		try(DaoSession session = env.createSession()) {
			...
		}
	}
}