Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.tika.eval.db; import java.nio.file.Path; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.HashSet; import java.util.Set; import org.apache.commons.io.FilenameUtils; public class H2Util extends JDBCUtil { private final static String DRIVER_CLASS = "org.h2.Driver"; private final Path db; public H2Util(Path db) { super(getConnectionString(db, true), DRIVER_CLASS); this.db = db; } public static boolean databaseExists(Path db) { String connString = getConnectionString(db, false); try (Connection conn = DriverManager.getConnection(connString)) { } catch (SQLException e) { return false; } return true; } @Override public String getJDBCDriverClass() { return "org.h2.Driver"; } @Override public boolean dropTableIfExists(Connection conn, String tableName) throws SQLException { Statement st = conn.createStatement(); String sql = "drop table if exists " + tableName; boolean success = st.execute(sql); st.close(); return success; } @Override public String getConnectionString() { return getConnectionString(db, true); } private static String getConnectionString(Path db, boolean createDBIfItDoesntExist) { String s = "jdbc:h2:" + FilenameUtils.separatorsToUnix(db.toAbsolutePath().toString()); if (!createDBIfItDoesntExist) { s += ";IFEXISTS=TRUE"; } return s; } @Override public Set<String> getTables(Connection connection) throws SQLException { String sql = "SHOW TABLES"; Statement st = connection.createStatement(); ResultSet rs = st.executeQuery(sql); Set<String> tables = new HashSet<>(); while (rs.next()) { String table = rs.getString(1); tables.add(table); } return tables; } }