今天遇到一個問題，就是在mybatis傳值的時候，不管有沒有條件都會把我的<if>標籤裡面的條件給帶上

<if test="condition.crossIds!= null">
			and rdtl.CROSS_ID IN
			<foreach item="item" index="index" collection="condition.crossIds"
				open="(" separator="," close=")">
				#{item}
			</foreach>
</if>

就是不管我的crossIds裡面有沒有值，它都會把我這個條件給加上導致查詢報錯，

全部條件語句

<sql id="whereVoSql">
		where rdtl.IS_DEL = 0
		<if test="condition.devName != null">
			and rdtl.dev_name LIKE CONCAT('%',#{condition.devName},
			'%')
		</if>
		<if test="condition.crossIds!= null">
			and rdtl.CROSS_ID IN
			<foreach item="item" index="index" collection="condition.crossIds"
				open="(" separator="," close=")">
				#{item}
			</foreach>
		</if>
		<if test="condition.areaId != null">
			and rdtl.AREA_ID = #{condition.areaId}
		</if>
		<if test="condition.createTimeStart != null">
			and rdtl.CREATE_TIME &gt;= #{condition.createTimeStart}
		</if>
		<if test="condition.createTimeEnd != null">
			and rdtl.CREATE_TIME &lt; #{condition.createTimeEnd}
		</if>
		<if test="condition.devType != null">
			and rdtl.DEV_TYPE = #{condition.devType}
		</if>
		<if test="condition.isLinkTask != null">
			and rdtl.IS_LINK_TASK = #{condition.isLinkTask}
		</if>
		<if test="condition.badType != null">
			and rdtl.BAD_TYPE = #{condition.badType}
		</if>
		<if test="condition.CrossId != null">
			and rdtl.CROSS_ID = #{condition.CrossId}
		</if>
		<if test="condition.isImportantRoad != null">
			and rc.IS_IMPORTANT_ROAD = #{condition.isImportantRoad}
		</if>
		<if test="condition.isLinkDev != null">
			and ( SELECT count(CAMERA_ID) FROM rg_light_camera_link
			WHERE rdtl.ID=TRAFFIC_LIGHT_ID ) = #{condition.isLinkDev}
		</if>
	</sql>
 

完整的SQL語句

<select id="selectVoPage" resultMap="DevTrafficLightVo">
		SELECT
		rdtl.ID,
		rdtl.DEV_CODE,
		rdtl.DEV_NAME,
		rdtl.CROSS_ID,
		rdtl.IS_LINK_TASK,
		ra.AREANAME AS areaName,
		rdtl.DEV_ADDRESS,
	
		FROM
		rg_dev_traffic_light rdtl
		LEFT JOIN rg_task_devlight_link rtdl ON
		rdtl.ID = rtdl.LIGHT_DEV_ID
		LEFT JOIN rg_cross rc ON rdtl.CROSS_ID =
		rc.id
		LEFT JOIN rg_area ra ON rdtl.AREA_ID = ra.ID
		LEFT JOIN
		rg_light_camera_link rlcl ON rdtl.ID = rlcl.TRAFFIC_LIGHT_ID
		LEFT JOIN
		device_info di ON rlcl.CAMERA_ID = di.ID
		LEFT JOIN rg_light_group_link
		rlgl ON rdtl.ID = rlgl.TRAFFIC_LIGHT_ID
		LEFT JOIN rg_rgl_group_info
		rrgi ON rlgl.GROUP_ID = rrgi.ID

		<include refid="whereVoSql" />
		GROUP BY
		rdtl.ID
		ORDER BY
		CREATE_TIME DESC

		limit ${from}, ${size}
	</select>
 

為了省點空間，查詢的有些欄位我省略了，

我的crossIds這個欄位的controller層

List<Long> crossIds = new ArrayList<>();
		for(int i=0;i<list.size();i++){
			crossIds.add(list.get(i).getId());
		}

以分頁查詢條件傳遞到後臺。 

Object[][] objects = { { "devName", devName }, { "areaId", areaId }, { "devType", devType },
				{ "crossIds", crossIds }, { "createTimeStart", createTimeStart_ },
				{ "createTimeEnd", createTimeEnd_ }, { "isLinkTask", isLinkTask },
				{ "isImportantRoad", isImportantRoad }, { "isLinkDev", isLinkDev } };
		Map condition = super.getCondition(objects);
		pageInfo.setCondition(condition);
		pageInfo = devTrafficLightService.selectVoPage(pageInfo);

當我沒有傳條件到後臺時，會報錯

nested exception is java.sql.SQLException: sql injection violation, syntax error: syntax error, error in :'ROUP BY
		rdtl.ID
		ORDER BY
		CREA', expect BY, actual BY pos 2466, line 165, column 9, token BY : SELECT
		rdtl.ID,
		rdtl.DEV_CODE,
		rdtl.DEV_NAME,
		rdtl.CROSS_ID,
		rdtl.IS_LINK_TASK,
		ra.AREANAME AS areaName,
		rdtl.DEV_ADDRESS,
		
		rdtl.BAD_TYPE,
		rdtl.CREATE_TIME,

		di.DEVICE_NAME AS deviceName,
		di.IP AS ipAddress,
		rrgi. NAME AS
		
		FROM
		rg_dev_traffic_light rdtl
		LEFT JOIN rg_task_devlight_link rtdl ON
		rdtl.ID = rtdl.LIGHT_DEV_ID
		LEFT JOIN rg_cross rc ON rdtl.CROSS_ID =
		rc.id
		LEFT JOIN rg_area ra ON rdtl.AREA_ID = ra.ID
		LEFT JOIN
		rg_light_camera_link rlcl ON rdtl.ID = rlcl.TRAFFIC_LIGHT_ID
		LEFT JOIN
		device_info di ON rlcl.CAMERA_ID = di.ID
		LEFT JOIN rg_light_group_link
		rlgl ON rdtl.ID = rlgl.TRAFFIC_LIGHT_ID
		LEFT JOIN rg_rgl_group_info
		rrgi ON rlgl.GROUP_ID = rrgi.ID

		 
		where rdtl.IS_DEL = 0	 
			and rdtl.CROSS_ID IN
			 
		GROUP BY
		rdtl.ID
		ORDER BY
		CREATE_TIME DESC

		limit 0, 10

還是會把 where rdtl.IS_DEL = 0                  and rdtl.CROSS_ID IN  這句打印出來。

後來突然才發現，我傳的是集合，要做判斷

mybatis中判斷兩個集合是否為空

<if test="condition.crossIds!= null and condition.crossIds.size > 0">
			and rdtl.CROSS_ID IN
			<foreach item="item" index="index" collection="condition.crossIds"
				open="(" separator="," close=")">
				#{item}
			</foreach>
</if>