mybatis 主键自增 insert后返回主键

mybatis 主键自增?insert后返回主键 ：

<insert id="insertStudentAutoKey" parameterType="StudentEntity">      <selectKey keyProperty="studentID" resultType="String" order="BEFORE">              select nextval('student')       </selectKey>          INSERT INTO STUDENT_TBL (STUDENT_ID,                                    STUDENT_NAME,                                    STUDENT_SEX,                                    STUDENT_BIRTHDAY,                                    CLASS_ID)                 VALUES   (#{studentID},                           #{studentName},                           #{studentSex},                           #{studentBirthday},                           #{classEntity.classID})       </insert>

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