Where can I see the HSQL database and tables

Question

I have downloaded a hsqldb.jar and I set to project buildpath,then next I wrote the program

  Class.forName(\"org.hsqldb.jdbc.JDBCDriver\");
Connection conn         


        

Answer 1

You can dump your HSQL in-memory database.

AbstractTestDao:

public abstract class AbstractTestDao {

    /**
     * Generic method for persisting entities into database.
     *
     * @param entity Java object from a (hibernate) class annotated with @Entity
     */
     void persistEntity(T entity) {
        Session session = HibernateUtil.getSessionFactory().openSession();
        session.persist(entity);
        session.beginTransaction().commit();
        session.close();
    }

    /**
     * Generic method for retrieving entities from database.
     *
     * @param cls Object class
     * @param id  Entity unique identifier (Primary Key)
     * @return Casted Entity object from db
     */
     T getEntityById(Class cls, Long id) {
        Session session = HibernateUtil.getSessionFactory().openSession();
        T entity = cls.cast(session.load(cls, id));
        session.close();
        return entity;
    }

    /**
     * Don't forget to close your connection so that the in-mem db can release it resources.
     *
     * @return Connection object to the in-memory db HyperSQL.
     * @throws SQLException
     */
    public static Connection getNewConn() throws SQLException {
        return DriverManager.getConnection("jdbc:hsqldb:mem:testdb;shutdown=false", "SA", "");
    }   

    /**
     * Makes a script from the current in-memory database and place a txt file in a directory.
     * The script describes the current in-mem db including constrains.
     *
     * @param testName A String representing the junit test name used for describing the file.
     * @throws SQLException
     */
    void createDatabaseScript(final String testName) throws SQLException {

        final String filePath = new File("").getAbsolutePath();
        final String targetDir = "/target/Temp/Databasedump/";
        final String directoryPath = filePath.concat(targetDir);
        final File directory = new File(directoryPath);
        if (!directory.exists()) {
            directory.mkdir();
        }

        final String fileName = uniqueFileNameGenerator(directoryPath, testName);

        final Connection conn = getNewConn();
        Statement st = null;
        ResultSet rs = null;

        try {
            st = conn.createStatement();
            //Example: st.executeQuery("SCRIPT '../Temp/dump4.txt'")
            final String sqlStatement = String.format("SCRIPT '%s%s'", directoryPath, fileName);
            rs = st.executeQuery(sqlStatement);

        } finally {
            if (st != null) {
                st.close();
            }
            if (rs != null) {
                rs.close();
            }
            if (conn != null) {
                conn.close();
            }
        }               
    }

    /**
     * Search for a unique filename in a directory with 1 to 2147483647 (Integer.MAX_VALUE) possibilities per date.
     * May throw a StackOverflowError if all 2147483646 file names are given away.
     *
     * @param directoryPath - String representing the directory you want to use.
     * @param name          - String representing the filename you want to use.
     * @return String representing a unique filename
     */
    private String uniqueFileNameGenerator(final String directoryPath, final String name) {

        final DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
        final String todayDate = dateFormat.format(Calendar.getInstance().getTime());
        final Integer randomNumber = (int) (Math.random() * Integer.MAX_VALUE + 1);
        final String fileName = name + "_" + todayDate + "_" + randomNumber + ".txt";

        File file = new File(directoryPath + fileName);

        if (file.exists()) {
            return uniqueFileNameGenerator(directoryPath, name);
        }
        return fileName;
    }   
}

HSQL DB version:

    hsqldb
    hsqldb
    1.8.0.10