1.a 如果参数的类型是List, 则在使用时，collection属性要必须指定为 list
<select id="findByIdsMap" resultMap="BaseResultMap"> Select <include refid="Base_Column_List" /> from jria where ID in <foreach item="item" index="index" collection="list" open="(" separator="," close=")"> #{item} </foreach> </select>1.b 如果参数的类型是Array,则在使用时，collection属性要必须指定为 array
<select id="findByIdsMap" resultMap="BaseResultMap"> select <include refid="Base_Column_List" /> from jria where ID in <foreach item="item" index="index" collection="array" open="(" separator="," close=")"> #{item} </foreach> </select>2 当查询的参数有多个时,例如 findByIds(String name, Long[] ids) 这种情况需要特别注意，在传参数时，一定要改用Map方式, 这样在collection属性可以指定名称
Map<String, Object> params = new HashMap<String, Object>(2); params.put("name", name); params.put("ids", ids); mapper.findByIdsMap(params); <select id="findByIdsMap" resultMap="BaseResultMap"> select <include refid="Base_Column_List" /> from jria where ID in <foreach item="item" index="index" collection="ids" open="(" separator="," close=")"> #{item} </foreach> </select>完整的示例如下:
例如有一个查询功能，Mapper接口文件定义如下方法:
List<Jria> findByIds(Long... ids); <select id="findbyIds" resultMap="BaseResultMap"> select <include refid="Base_Column_List" /> from jria where ID in <foreach item="item" index="index" collection="array" open="(" separator="," close=")"> #{item} </foreach> </select>