mybatis 如何通过resultMap 返回long

<resultMap type='java.lang.Long'> <result column='budget' property='budget' javaType='long'/> </resultMap> mybatis long 类型返回为null报异常

Mapper method ’com.mpn.dao.TWeatherMapper.avgWeatherTemperature attempted to return null from a method with a primitive return type (long).

<select resultType='java.lang.Long' parameterType='java.lang.String' >SELECT IFNULL(AVG(WeatherTemperature),0) AS OrderAverage FROM t_weather WHERE WeatherDate= #{date,jdbcType=VARCHAR}; </select> <select resultType='java.lang.Long' parameterType='java.lang.String' >SELECT SUM(WeatherTemperature) AS OrderAverage FROM t_weather WHERE WeatherDate= #{date,jdbcType=VARCHAR}; </select> <select resultType='java.lang.Long' parameterType='java.lang.String' >SELECT IFNULL(AVG(WeatherHumidity),0) AS OrderAverage FROM t_weather WHERE WeatherDate= #{date,jdbcType=VARCHAR}; </select>

由于返回为空long中没有此类型所以抛异常，改为

<!-- 根据日期来进行计算平局值与 --> <select resultType='java.lang.Long' parameterType='java.lang.String' >SELECT IFNULL(AVG(WeatherTemperature),0) AS OrderAverage FROM t_weather WHERE WeatherDate= #{date,jdbcType=VARCHAR}; </select> <select resultType='java.lang.Long' parameterType='java.lang.String' >SELECT IFNULL(SUM(WeatherTemperature),0) AS OrderAverage FROM t_weather WHERE WeatherDate= #{date,jdbcType=VARCHAR}; </select> <select resultType='java.lang.Long' parameterType='java.lang.String' >SELECT IFNULL(AVG(WeatherHumidity),0) AS OrderAverage FROM t_weather WHERE WeatherDate= #{date,jdbcType=VARCHAR}; </select>

用IFNULL来进行判断！

以上为个人经验，希望能给大家一个参考，也希望大家多多支持好吧啦网。