private SqlSession session = null;

    @BeforeClass
    public void init() throws IOException {
        // SqlSession--->SqlSessionFatory----->SqlSessionFatoryBuilder
        SqlSessionFactoryBuilder ssb = new SqlSessionFactoryBuilder();
        InputStream ins = Resources.getResourceAsStream("mybatis.xml");
        SqlSessionFactory ssf = ssb.build(ins);
        session = ssf.openSession();
    }

    public static void main(String[] args) throws IOException {

        SqlSessionFactoryBuilder ssb = new SqlSessionFactoryBuilder();
        InputStream ins = Resources.getResourceAsStream("mybatis.xml");
        SqlSessionFactory ssf = ssb.build(ins);
        SqlSession   session = ssf.openSession();
        User user = session.selectOne("cn.java.dao.impl.One2ManyImpl.one2Many");
        System.out.println(user);
    }

    @Test
    public void one2Many() {
        User user = session.selectOne("cn.java.dao.impl.One2ManyImpl.one2Many");
        System.out.println(user);
    }a

    @Test
    public void addUser() {
        User user = new User();
        user.setPassword("456");
        user.setUsername("aaa");
        System.out.println(user);
        int result = session.insert("cn.java.dao.impl.One2ManyImpl.addUser", user);
        // session.commit();
        System.out.println("result=" + result);// result代表的是影響的行數
        System.out.println("當前插入數據的主鍵為=" + user.getId());
    }

    @Test
    public void userAdd() {
        Map<String, Object> map = new HashMap<String, Object>();
        int result = session.insert("cn.java.dao.impl.One2ManyImpl.userAdd", map);
        session.commit();
        System.out.println("result=" + result);// result代表的是影響的行數
        System.out.println("當前插入數據的主鍵為=" + map.get("id"));
 

xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="cn.java.dao.impl.One2ManyImpl" >
  <resultMap id="BaseResultMap" type="cn.java.entity.User" >
   <result property="id" javaType="Long" column="id"/>
   <result property="username" javaType="String" column="username"/>
   <result property="password" javaType="String" column="password"/>
   <collection property="orderList" ofType="cn.java.entity.Order">
        <id column="orderId" property="orderid" jdbcType="BIGINT" />
        <result column="orderName" property="ordername" jdbcType="VARCHAR" />
        <result column="price" property="price" jdbcType="REAL" />
        <result column="userId" property="userid" jdbcType="BIGINT" />
   </collection>
  </resultMap>

  <select id="one2Many" resultMap="BaseResultMap">
    select * from users u inner join orders o on  u.id=o.`userId`
  </select>

  <!-- 
    useGeneratedKeys：使用主鍵作為返回值
    keyProperty：將主鍵值封裝到某一個實體類中對應的屬性中
   -->
  <insert id="addUser" useGeneratedKeys="true" parameterType="cn.java.entity.User" keyProperty="id">
    INSERT INTO users SET username=#{username},PASSWORD=#{password}
  </insert>

  <insert id="userAdd" useGeneratedKeys="true" keyProperty="id" parameterType="Map">
    INSERT INTO users SET username=‘xxx‘,PASSWORD=‘xxx‘
  </insert>

</mapper>
 

通過mybatis添加數據記錄時，如何返回主鍵