Mybatis在oracle数据库中插入数据后返回自增ID值

Mybatis 示例之 SelectKey：http://blog.csdn.net/isea533/article/details/21153791

1. Oracle数据库中创建自增序列

create sequence SEQ_USER_ID
start with 1 
increment by 1 
minvalue 1 
nomaxvalue
nocycle

2. mybatis的mapper.xml中：

（selectKey的结果会放进传参user对象中）

  <insert id="createUser" parameterType="pojo.User">
	<selectKey keyProperty="userId" resultType="int" order="BEFORE">  
    	select SEQ_USER_ID.NEXTVAL from dual  
	</selectKey>
    insert into "USER" (USER_ID, USER_NAME, PASSWORD)
    values (#{userId,jdbcType=DECIMAL}, #{userName,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR}
      )
  </insert>

3. 

User user = new User();
user.setUserName("abc");
user.setPassword("abc");
System.out.println(userService.createUser(user));
System.out.println(user.getUserId());

插入成功则输出1和userId值。