使用 <selectKey>标签，keyProperty设置生成的UUID所绑定的属性，如设置为id，即会将值绑定到参数对象User的id属性上；order属性设置为BEFORE，先执行selectKey语句
<insert id="save" parameterType="User">
<selectKey keyProperty="id" resultType="string" order="BEFORE">
select replace(uuid(), '-', '') as id from dual
</selectKey>
insert into t_user(id, user_sex) values( #{id}, #{user_sex} )
</insert>
使用@SelectKey注解，属性和<selectKey>标签类似。before属性设置为true，类似于<selectKey>标签order属性设置为BEFORE
@Insert("insert into t_user(id, user_sex) values(#{id}, #{user_sex})")
@SelectKey(keyProperty = "id", resultType = String.class, before = true,
statement = "select replace(uuid(), '-', '') as id from dual")
public int save(User user);
测试代码：
User user = new User();
user.setUser_age(22);
user.setUser_sex(1);
int count = userMapper.save(user);
System.out.println("count：" + count);
System.out.println("id：" + user.getId());
