class testGo {  public static void IsReg(String username, String openid) {   Connection con = new Dbcon().getCon();   ResultSet rs = null;   String sql = null;    try {        sql = "select * from A where id=1";    rs = con.prepareStatement(sql).executeQuery();    while (rs.next()) {     System.out.println(rs.getBoolean("enabled"));    }        sql="update A set enabled=true where id=1";    con.createStatement().execute(sql);        sql = "select * from A where id=1";    rs = con.prepareStatement(sql).executeQuery();    while (rs.next()) {     System.out.println(rs.getBoolean("enabled"));    }        con.close();   } catch (Exception e) {    e.printStackTrace();   }  } }