在java中从预准备语句中获取值

Question

我需要你帮我准备好那份声明。我想在转换映射有像以前的2个映射的总和的值。请帮帮我

 statement = connection.prepareStatement("select count(*) as count,b.bankid,status from................... between ? and ? group by status,bankid order by bankid");
                statement.setInt(1, PaymentType.CONVERSION);
                statement.setTimestamp(2, dateFrom);
                statement.setTimestamp(3, dateTo);
                rs = statement.executeQuery();
                while (rs.next()) {
                    int status = rs.getInt("status");
                    String bankid =rs.getString("bankid");

                    if (status == 1) {
                        suc.put(bankid, rs.getInt("count"));
                    }else {
                        fail.put(bankid, rs.getInt("count"));
                    }
                    conv.put(bankid, success.get("count") + failed.get("count"));

Answer 1

您为success和failed映射使用了错误的密钥。

success.get("count") + failed.get("count")

应该是

success.get(bankid) + failed.get(bankid)

您还应该防止success或failed映射从get返回null，以防在计算表达式时这些映射没有bankid条目。

例如：

public Integer safeGet(Map<String, Integer> map, String key) {
  if (map == null || key == null || !map.containsKey(key)) {
    return Integer.valueOf(0);
  }
  return map.get(key);
}

然后使用：

conversion.put(bankid, safeGet(success, bankid) + safeGet(failed, bankid));