oracle+ mybatis 插入数据时返回插入uuid

<insert id="addTask" parameterType="Task">
<selectKey resultType="String" keyProperty="uuid" order="BEFORE">
SELECT sys_guid() FROM DUAL
</selectKey>
insert into t_zone_task values(#{uuid}, #{title}, #{author}, #{subjectId}, sysdate, #{duration}, #{state})
</insert>

public void addTask(Task task) {
System.out.println("before:" + task.getUuid());
taskMapper.addTask(task);
System.out.println("after:" + task.getUuid());
}