mybatis返回int或者Integer类型报错

来源：互联网发布：中国光伏行业协会数据编辑：程序博客网时间：2024/06/05 04:26

会报错如下：

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.apache.ibatis.binding.BindingException: Mapper method 'com.bill.springMybatis.dao.UserDao.getUserIdByName attempted to return null from a method with a primitive return type (int).
   org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.Java:894)
   org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
   javax.servlet.http.HttpServlet.service(HttpServlet.java:734)
   javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
   org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
   org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)

返回类型设置为封装类型Integer或者基本类型int，都有可能出错

例如

<select id="queryPaySum" resultType="java.lang.Integer" parameterType="map" >select  sum(p.CASH_FEE)  from PAY_INFO pwhere 1=1  and p.TRADE_RESULT_CODE = #{traderesultcode}</select>

我用的oracle 利用 nvl()函数解决问题

<select id="queryPaySum" resultType="java.lang.Integer" parameterType="map" >select  nvl(sum(p.CASH_FEE), 0)  from PAY_INFO pwhere 1=1  and p.TRADE_RESULT_CODE = #{traderesultcode}</select>

用 ISNULL(), NVL(), IFNULL() and COALESCE() 函数替换空值

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