**方式一，useGeneratedKeys** **1.UserMapper.java** ~~~ //新增并獲取主鍵值 int save1(User u); ~~~ **2.UserMapper.xml** ~~~ <!--useGeneratedKeys:是否使用自增主鍵 --> <!--keyProperty:對應到實體屬性中--> <insert id="save1" parameterType="User" useGeneratedKeys="true" keyProperty="id"> insert into t_user(u_name,u_password) values(#{name},#{password}) </insert> ~~~ **3.測試代碼** ~~~ @Test public void save1(){ UserMapper mapper = session.getMapper(UserMapper.class); User u = new User(); u.setName("test"); u.setPassword("hello"); System.out.println(mapper.save1(u)); System.out.println(u.getId()); } ~~~ **方式二，使用select LAST\_INSERT\_ID()** **1.UserMapper.java** ~~~ //新增并獲取主鍵值 int save1(User u); ~~~ **2.UserMapper.xml** ~~~ <!--keyColumn:主鍵對應數據庫的字段--> <!--keyProperty:主鍵對應實體屬性--> <!--order:Insert語句之前還是之后--> <!--resultType:主鍵值類型--> <insert id="save1" parameterType="User"> <selectKey keyColumn="u_id" keyProperty="id" order="AFTER" resultType="int"> select LAST_INSERT_ID() </selectKey> insert into t_user(u_name,u_password) values(#{name}, #{password}) </insert> ~~~ **3.測試代碼** ~~~ @Test public void save1(){ UserMapper mapper = session.getMapper(UserMapper.class); User u = new User(); u.setName("test11"); u.setPassword("hello"); System.out.println(mapper.save1(u)); System.out.println(u.getId()); } ~~~