boolean - 返回一个 boolean 值 - jdbcTemplate

Question

我想在此方法中使用返回一个 boolean 值:

public Boolean isSizeOk(String transactionId){ 
    String sqlQuery = "SELECT true FROM customer_pool WHERE id = "+ transactionID + " AND level = 13)";

//The next line is the problem. 
    //If I am returning a Boolean List, I can write

    List <Boolean> sizeResult = jdbcTemplate.queryForList(sqlQuery, Boolean.class, transactionId);

    //But since I only want a boolean value, what will the statement be?
     Boolean sizeResult = jdbcTemplate......?

    return sizeResult;
}

请帮忙。谢谢。

Answer 1

如果要编写一个方法来检查数据库中是否存在记录，可以使用以下代码:

Integer cnt = jdbcTemplate.queryForObject(
    "SELECT count(*) FROM customer_pool WHERE id = ? AND level = 13)", Integer.class, id);
return cnt != null && cnt > 0