libepg.util.db.JDBCAccessor.java Source code

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Here is the source code for libepg.util.db.JDBCAccessor.java

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package libepg.util.db;

import java.lang.invoke.MethodHandles;
import java.sql.DriverManager;
import java.sql.SQLException;
import loggingsupport.loggerfactory.LoggerFactory;
import org.apache.commons.logging.Log;

/**
 *
 * @author dosdiaopfhj
 */
public class JDBCAccessor implements AutoCloseable {

    /**
     * false?????????????
     */
    public static final boolean CLASS_LOG_OUTPUT_MODE = true;

    private static final Log LOG;

    static {
        final Class<?> myClass = MethodHandles.lookup().lookupClass();
        LOG = new LoggerFactory(myClass, JDBCAccessor.CLASS_LOG_OUTPUT_MODE).getLOG();
    }

    private static JDBCAccessor instance;
    private static java.sql.Connection con = null;

    private JDBCAccessor() {
        // ??????
        instance = null;
    }

    public static synchronized JDBCAccessor getInstance() {
        // ???????????
        // ????
        if (instance == null) {
            instance = new JDBCAccessor();
        }
        return instance;
    }

    /**
     * jdbc?DB??????????
     *
     * @author dosdiaopfhj
     * @see java.lang.Class.forName
     * @param url (DB???)
     * @param user DB???
     * @param password DB?
     *
     */
    public final synchronized void connect(String url, String user, String password) {
        try {
            this.close();
            // DB?
            con = DriverManager.getConnection(url, user, password);
            LOG.trace("DB?");
        } catch (SQLException ex) {
            con = null;
            LOG.fatal("DB", ex);
        }
    }

    /**
    * jdbc?DB??????????
    *
    * @author dosdiaopfhj
    * @see java.lang.Class.forName
    * @param url (DB???)
    *
    */
    public final synchronized void connect(String url) {
        try {
            this.close();
            // DB?
            con = DriverManager.getConnection(url);
            LOG.trace("DB?");
        } catch (SQLException ex) {
            con = null;
            LOG.fatal("DB", ex);
        }
    }

    /**
     * ??
     *
     * @return ???null
     */
    public final synchronized java.sql.Connection getConnection() {
        return con;
    }

    /**
     * DB?? ?????????
     *
     */
    @Override
    public final synchronized void close() {
        LOG.trace("DB???");
        try {
            if (con != null) {
                con.close();
                LOG.trace("DB?");
            } else {
                LOG.trace("?DB????????????");
            }
        } catch (SQLException ex) {
            LOG.fatal("DB", ex);
        } finally {
            con = null;
        }
    }

}