genauEinDatensatz
boolean genauEinDatensatz = false;Connection conn = null;PreparedStatement ps = null;ResultSet rs = null;try{ conn = ...; ps = conn.prepareStatement("SELECT COUNT(*) FROM ... WHERE ..."); rs = ps.executeQuery(); rs.next(); genauEinDatensatz = (rs.getLong(1) == 1);}finally{ if (rs != null) { try { rs.close(); } catch (SQLException e) {} } if (ps != null) { try { ps.close(); } catch (SQLException e) {} } if (conn != null) { try { conn.close(); } catch (SQLException e) {} }}