//第一种方法<udpate id ="方法名" parameter ="java.util.List">
update `表名`
<trim prefix ="set" suffixOverrides =","><trim prefix ="字段1 = case" suffix="end,"><foreach collection ="list" item ="item" index ="index">
when ID = #{item.ID} then #{item.参数1}</foreach></trim><trim prefix ="字段2 = case" suffix ="end,"><foreach collection ="list" item ="item" index ="index">
when ID = #{item.ID} then #{item.参数2}</foreach></trim></trim>
where
<foreach collection ="list" separator ="or" item ="item" index ="index">
ID = #{item.ID}</foreach></update>//第二种方法<update id ="方法名" parameterType ="java.util.List"><foreach collection ="list" item ="item" index ="index" open ="begin" close=";end;" separator =";">
UPDATE '表'<set><if test ="item.参数1!=null and item.参数1 !=""toString()">'对应表字段1'= #{item.参数1}</if><if test ="item.参数2!=null and item.参数2 !="".toString()">'对应表字段2'= #{item.参数2}</if></set>
where id = #{item.id}</foreach></update>
