摘要： preparedstatement的sql语句不能用？=？，想要用的话用如下方法DBconn DB = new DBconn(); Connection con = DB.getConn(); String sql = "SELECT * FROM server,node WHERE server.node_id=node.id GROUP BY hostname;"; String sqlss = "select * from server,node where server.node_id=node.id and %column%=?;";//加百分 阅读全文