@GetMapping("/generateOldCarModelRanking")
@ApiOperation("老旧车车型排名")
public Result generateOldCarModelRanking(@RequestParam(value = "year")String year,@RequestParam(value = "isCommercial")boolean isCommercial ,@RequestParam(value = "fuelType")String fuelType,@RequestParam(value = "pageNum")int pageNum,@RequestParam(value = "pageSize")int pageSize){
        log.info("老旧车车型排名,isCommercial:{},fuelType:{},pageNum:{},pageSize:{}",isCommercial,fuelType,pageNum,pageSize);
        return vehicleBaseInfoService.generateOldCarModelRanking(year,isCommercial,fuelType,pageNum,pageSize);
}

这是我的接口，注意参数

fuelType 是String类型的

我来测试接口：

然后看见idea报错：

Error querying database.  Cause: java.lang.NumberFormatException: For input string: "A"
Cause: java.lang.NumberFormatException: For input string: "A"

看看我的sql，其中有一句

<if test="fuelType != null and fuelType != ''">
      and vbi.FUEL_TYPE = #{fuelType}
     <if test="fuelType == 'A' and year != null and year != ''">
         and TIMESTAMPDIFF(YEAR,vbi.REGISTER_DATE,'${year}-12-31')+1 &gt; 8
     </if>
     <if test="fuelType == 'B' and year != null and year != ''">
         and TIMESTAMPDIFF(YEAR,vbi.REGISTER_DATE,'${year}-12-31')+1 &gt; 5
     </if>
</if>

 错误原因

我将String类型的fuelType和Char类型的'A'进行了比较。mybatis认为拿一个字符串（String）和一个字符(char)比较，也会报错

解决办法

转成字符串：'A'.toString()

<if test="fuelType != null and fuelType != ''">
    and vbi.FUEL_TYPE = #{fuelType}
    <if test="fuelType == 'A'.toString() and year != null and year != ''">
        and TIMESTAMPDIFF(YEAR,vbi.REGISTER_DATE,'${year}-12-31')+1 &gt; 8
    </if>
    <if test="fuelType == 'B'.toString() and year != null and year != ''">
        and TIMESTAMPDIFF(YEAR,vbi.REGISTER_DATE,'${year}-12-31')+1 &gt; 5
    </if>
</if>

参考：java - mybatis参数格式化异常:NumberFormatException: For input string:"xx" - 呆萌的程序猿 - SegmentFault 思否