Question

gomap_controller.java

List<String> room = new ArrayList<String>();
Map searchConditions = new HashMap<>();
searchConditions.put("room", room);
List<Map> rList = rd.getRoomList(searchConditions);

室温mapper.xml

<select id="getRoomList" resultType="java.util.HashMap"
        parameterType="java.util.HashMap">
<choose>
            <when
                test="underground != '' or low_floor != '' or mid_floor != '' or high_floor != ''">
                B_FLOOR IN
                <foreach collection="room" item="item" index="index"
                    separator="," open="(" close=")AND">
                    #{item}
                </foreach>
            </when>
        </choose>

现在我收到错误###错误查询数据库。原因：org.apache.ibatis.builder.BuilderException：表达式＆＃39; room＆＃39;评估为空值。

Answer 1

您在测试中没有评估空集合。看起来您正在对地图中的键执行验证？基于你在那里的一小段代码，我希望看到这个评价而不是你所拥有的......

SELECT ...
FROM ...
<choose>
  <when test="room" != 'null'>
    WHERE B_FLOOR IN
      <foreach collection="room" item="item" index="index" separator="," open="(" close=")AND">
           #{item}
      </foreach>
  </when>
</choose>

mybatis builder exception表达式＆＃39; room＆＃39;评估为空值

1 个答案: