java获得数据库主键信息

public String getPrimaryName(Connection conn)  throws Exception{DatabaseMetaData md = conn.getMetaData();ResultSet rs = md.getPrimaryKeys(null, null, "gsm_alert_check");while(rs.next()){System.out.println(rs.getString("TABLE_CAT"));System.out.println(rs.getString("TABLE_SCHEM"));System.out.println(rs.getString("TABLE_NAME"));System.out.println(rs.getString("COLUMN_NAME"));System.out.println(rs.getString("KEY_SEQ"));System.out.println(rs.getString("PK_NAME"));}rs.close();return null;}