Java JDBC H2 Connection getH2Connection(String filename)

Description

get H Connection

License

Open Source License

Declaration

public static Connection getH2Connection(String filename) 

Method Source Code

//package com.java2s;
//License from project: Open Source License 

import java.io.File;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class Main {
    public static Connection getH2Connection(String filename) {
        try {/*from  ww  w.  j av a  2 s .  c o m*/
            System.setProperty("h2.serverCachedObjects", "200000");
            Class.forName("org.h2.Driver");
            return DriverManager.getConnection(String.format(
                    "jdbc:h2:%s;DB_CLOSE_ON_EXIT=FALSE;TRACE_LEVEL_FILE=3",
                    new File(filename).getAbsolutePath()), "sa", "");
        } catch (ClassNotFoundException e) {
            throw new RuntimeException("ERROR: Couldn't load H2 db driver");
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * A helper method to get the global default RDBMS connection.
     * 
     * @param filename
     * @return
     */
    public static Connection getConnection(String filename) {
        return getDerbyConnection(filename);
    }

    public static Connection getDerbyConnection(String filename) {
        try {
            // Check if the database exists. If it doesn't, append ;create=true to
            // the URL.
            File db = new File(filename);
            boolean exists = false;

            if (!db.exists()) {
                // Check for files that have the same prefix in this directory
                for (File child : db.getParentFile().listFiles()) {
                    if (child.getName().startsWith(db.getName())) {
                        exists = true;
                    }
                }
            }

            System.setProperty("derby.stream.error.file", "error.txt");
            System.setProperty("derby.system.home", db.getParent());

            // Largest page size Derby allows. This will reduce the number of I/O 
            // operations and speed things up a bit.
            System.setProperty("derby.storage.pageSize", "32768");
            // Larger page cache will speed things up. TODO: determine this dynamically
            // from Runtime.getRuntime().
            // 32KB page size / 10K cache size ~= 312MB of memory (not including 
            // overhead).
            //System.setProperty("derby.storage.pageCacheSize", "10000");

            Class.forName("org.apache.derby.jdbc.EmbeddedDriver")
                    .newInstance();
            String url = String.format("jdbc:derby:%s",
                    db.getAbsolutePath());

            if (!exists) {
                url = url.concat(";create=true");
            }

            return DriverManager.getConnection(url);
        } catch (ClassNotFoundException e) {
            throw new RuntimeException("Failed to load Derby db driver!", e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        } catch (InstantiationException e) {
            throw new RuntimeException("Failed to load Derby db driver!", e);
        } catch (IllegalAccessException e) {
            throw new RuntimeException("Failed to load Derby db driver!", e);
        }
    }
}

Related

1. createDBWithTB(String db)
2. deleteDatabase()
3. deleteDatabaseH2()
4. getConnection()
5. getH2Connection(String dbname)
6. isH2DbAlreadyRunning()
7. rollback(Savepoint sp)
8. setAutoCommit(Boolean b)