<insert id="insert" parameterType="Person" useGeneratedKeys="true" keyProperty="id">
    insert into person(name,pswd) values(#{name},#{pswd})
</insert>

int insert(Person person);

Person person = new Person("name","psw");
//num是插入的记录数
int num = PersonMapper.insert(person);
//person对象的id属性会变成自生成的id
int id = person.getId();