8-动态sqlr-set

int updateStudent(Student student);

<update id="updateStudent" parameterType="student">
       update `student`
       <set>
           <if test="name != null">
               `name` = #{name},
           </if>
           <if test="age != null">
               `age` = #{age},
           </if>
           <if test="gender != null">
               `gender` = #{gender,typeHandler=genderTypeHandler}
           </if>
       </set>
       where `id` = #{id}
   </update>

@Test
public void test() {
    SqlSession session = factory.openSession();
    try {
        StudentMapper studentMapper = session.getMapper(StudentMapper.class);
        int id = 10001;
        String name = "hu";
        int age = 18;
        GenderEnum gender = GenderEnum.getGender(1);
        Student student = new Student(id,name,age,gender);
        int affectedRows = studentMapper.updateStudent(student);
        System.out.println(affectedRows);
        System.out.println(studentMapper.selectStudentById(id));
    } finally {
        session.commit();
        session.close();
    }
}