mysql如何向mongodb转化

/**
* 校验用户名是否注册
* @param loginname
* @return
* @throws SQLException
*/
public boolean ajaxValidateLoginname(String loginname) throws SQLException {
String sql = "select count(1) from t_user where loginname=?";
Number number = (Number)qr.query(sql, new ScalarHandler(), loginname);
return number.intValue() == 0;
}

/**
 * 校验Email是否注册
 * @param email
 * @return
 * @throws SQLException
 */
public boolean ajaxValidateEmail(String email) throws SQLException {
    String sql = "select count(1) from t_user where email=?";
    Number number = (Number)qr.query(sql, new ScalarHandler(), email);
    return number.intValue() == 0;
}
/**
 * 用户名注册校验
 * @param loginname
 * @return
 */
public boolean ajaxValidateLoginname(String loginname) {
    try {
        return userDao.ajaxValidateLoginname(loginname);
    } catch (SQLException e) {
        throw new RuntimeException(e);
    }
}

/**
 * Email校验
 * @param email
 * @return
 */
public boolean ajaxValidateEmail(String email) {
    try {
        return userDao.ajaxValidateEmail(email);
    } catch (SQLException e) {
        throw new RuntimeException(e);
    }
}

这是用mysql语法写的，如果用的是mongo该怎么写呢，求教

http://www.2cto.com/database/201409/339229.html

http://www.xue163.com/328/1654/3286149.html

这不是我想要的啊 我想知道mongodb的写法