Play - - DBPlugin

• 启动时创建连接

class DBPlugin ..{
    public void onApplicationStart() {
      if (changed()) {
        try{
         Properties p = Play.configuration;
         if (DB.datasource != null) {
             DB.destroy();
         }
         boolean isJndiDatasource = false;
         if (datasourceName.startsWith("jndi:")) {
            datasourceName = datasourceName.substring("jndi:".length());
             isJndiDatasource = true;
         }
         //搜索JNDI 
         if (isJndiDatasource || datasourceName.startsWith("java:")) {

            Context ctx = new InitialContext();
            DB.datasource = (DataSource) ctx.lookup(datasourceName);

           }else {
             String driver = p.getProperty("db.driver");
                    try {
                        Driver d = (Driver) Class.forName(driver, true, Play.classloader).newInstance();
                        DriverManager.registerDriver(new ProxyDriver(d));
                    } catch (Exception e) {
                        throw new Exception("Driver not found (" + driver + ")");
                    }

                    // Try the connection
                    Connection fake = null;
                    try {
                        if (p.getProperty("db.user") == null) {
                            fake = DriverManager.getConnection(p.getProperty("db.url"));
                        } else {
                            fake = DriverManager.getConnection(p.getProperty("db.url"), p.getProperty("db.user"), p.getProperty("db.pass"));
                        }
                    } finally {
                        if (fake != null) {
                            fake.close();
                        }
                    }
            ComboPooledDataSource ds = new ComboPooledDataSource();
             ......
           } 
      }


    }
     public void onApplicationStop() {
        if (Play.mode.isProd()) {
            DB.destroy();
        }
    }
    private static boolean changed() {
        Properties p = Play.configuration;
        获取一些配置信息到properties
    }
   public static class PlayConnectionCustomizer implements ConnectionCustomizer {

        public static Map<String, Integer> isolationLevels;

        static {
            isolationLevels = new HashMap<String, Integer>();
            isolationLevels.put("NONE", Connection.TRANSACTION_NONE);
            isolationLevels.put("READ_UNCOMMITTED", Connection.TRANSACTION_READ_UNCOMMITTED);
            isolationLevels.put("READ_COMMITTED", Connection.TRANSACTION_READ_COMMITTED);
            isolationLevels.put("REPEATABLE_READ", Connection.TRANSACTION_REPEATABLE_READ);
            isolationLevels.put("SERIALIZABLE", Connection.TRANSACTION_SERIALIZABLE);
        }

        public void onAcquire(Connection c, String parentDataSourceIdentityToken) {
            Integer isolation = getIsolationLevel();
            if (isolation != null) {
                try {
                    Logger.trace("Setting connection isolation level to %s", isolation);
                    c.setTransactionIsolation(isolation);
                } catch (SQLException e) {
                    throw new DatabaseException("Failed to set isolation level to " + isolation, e);
                }
            }
        }

        public void onDestroy(Connection c, String parentDataSourceIdentityToken) {}
        public void onCheckOut(Connection c, String parentDataSourceIdentityToken) {}
        public void onCheckIn(Connection c, String parentDataSourceIdentityToken) {}

        /**
         * Get the isolation level from either the isolationLevels map, or by
         * parsing into an int.
         */
        private Integer getIsolationLevel() {
            String isolation = Play.configuration.getProperty("db.isolation");
            if (isolation == null) {
                return null;
            }
            Integer level = isolationLevels.get(isolation);
            if (level != null) {
                return level;
            }

            try {
                return Integer.valueOf(isolation);
            } catch (NumberFormatException e) {
                throw new DatabaseException("Invalid isolation level configuration" + isolation, e);
            }
        }
    }
}