save Rss Feed using embedded derby - Java java.sql

Java examples for java.sql:Derby

  1. HOME
  2. Java
  3. java.sql
  4. Derby

Description

save Rss Feed using embedded derby

Demo Code


import java.sql.*;
import java.util.*;

public class Main{
    final static Properties props = new Properties();
    private static String framework = "embedded";
    private static String driver = "org.apache.derby.jdbc.EmbeddedDriver";
    private static String protocol = "jdbc:derby:";
    public static int saveRssFeed(RssFeed rssFeed) {
        int pk = rssFeed.link.hashCode();

        loadDriver();//www  . ja  v  a  2 s. c  o  m

        Connection conn = null;
        ArrayList statements = new ArrayList();
        PreparedStatement psInsert = null;
        Statement s = null;
        ResultSet rs = null;
        try {

            // database name
            String dbName = "demoDB";

            conn = DriverManager.getConnection(protocol + dbName
                    + ";create=true", props);

            rs = conn.createStatement().executeQuery(
                    "select count(id) from rssFeed where id = "
                            + rssFeed.link.hashCode());

            rs.next();
            int count = rs.getInt(1);

            if (count == 0) {

                // handle transaction
                conn.setAutoCommit(false);

                s = conn.createStatement();
                statements.add(s);

                psInsert = conn
                        .prepareStatement("insert into rssFeed values (?, ?, ?)");
                statements.add(psInsert);
                psInsert.setInt(1, pk);
                String escapeTitle = rssFeed.channelTitle.replaceAll("\'",
                        "''");
                psInsert.setString(2, escapeTitle);
                psInsert.setString(3, rssFeed.link);
                psInsert.executeUpdate();
                conn.commit();
                System.out.println("Inserted " + rssFeed.channelTitle + " "
                        + rssFeed.link);
                System.out.println("Committed the transaction");
            }
            shutdown();
        } catch (SQLException sqle) {
            sqle.printStackTrace();
        } finally {
            // release all open resources to avoid unnecessary memory usage

            // ResultSet
            close(rs);

            // Statements and PreparedStatements
            int i = 0;
            while (!statements.isEmpty()) {
                // PreparedStatement extend Statement
                Statement st = (Statement) statements.remove(i);
                close(st);
            }

            //Connection
            close(conn);

        }

        return pk;
    }
    private static void loadDriver() {

        try {
            Class.forName(driver).newInstance();
            System.out.println("Loaded driver");

        } catch (Exception e) {
            e.printStackTrace();
        }

    }
    private static void shutdown() {
        // standard checking code when shutting down database.
        // code from http://db.apache.org/derby/
        if (framework.equals("embedded")) {
            try {
                // the shutdown=true attribute shuts down Derby
                DriverManager.getConnection("jdbc:derby:;shutdown=true");

            } catch (SQLException se) {
                if (((se.getErrorCode() == 50000) && ("XJ015".equals(se
                        .getSQLState())))) {
                    System.out.println("Derby shut down normally");
                } else {
                    System.err.println("Derby did not shut down normally");
                    se.printStackTrace();
                }
            }
        }
    }
    private static void close(AutoCloseable closable) {
        try {
            if (closable != null) {
                closable.close();
                closable = null;
            }
        } catch (Exception sqle) {
            sqle.printStackTrace();
        }
    }
}

Related Tutorials