Question

请向我解释

之间的不同之处

private boolean inUse(JDBCTemplates jdbc, BigInteger firmwareId) {
               String query = "select * from references ref " +
                "where ref.attr_id = 9 " +
                "and ref.reference = ?";
        try { 
               s = (String) jdbc.selectForObject(query....);
            } catch (Exception e) {
               log.info(e.toString());
            }
        return ...;
}

和

private boolean inUse(JDBCTemplates jdbc, BigInteger firmwareId) {
              String query = "select * from references ref " +
              "where ref.attr_id = 9 " +
              "and ref.reference =" + firmwareId;
        try { 
              s = (String) jdbc.selectForObject(query....);
            } catch (Exception e) {
              log.info(e.toString());
            }
        return ...;
}

在第二种情况下，我收到了数据库的访问错误（ jdbc.DataAccessException：由于访问数据库而导致错误），并且在第一种情况下一切正常。

Answer 1

尝试以这种方式修改代码，注意字符串查询和参数：

private boolean inUse(JDBCTemplates jdbc, BigInteger firmwareId) {
          String query = "select * from references ref " +
          "where ref.attr_id = 9 " +
          "and ref.reference ='" + firmwareId+"'";//Here might be the error
    try { 
          s = (String) jdbc.selectForObject(query....);
        } catch (Exception e) {
          log.info(e.toString());
        }
    return ...;

}

尝试这个，让我们知道它是否有效，以便我们可以尝试别的东西

访问数据库时出错

1 个答案: