海阔天空

手机扫码查看

2020java框架教程之mybatis的增删改查CRUD

查询：

mapper：

<!-- 通过 id 查询用户 -->
<select id="selectUser" resultType="Users" parameterType="int">
    select * from users where id = #{id}
</select>
<!--  设置 ResultMap -->
<resultMap id="usersResultMap" type="Users">
    <id column="id" property="id" jdbcType="INTEGER"/>
    <!-- 将 password 设置 pwd 为别名 -->
    <result column="pwd" property="password" jdbcType="VARCHAR"/>
</resultMap>
<!--  通过 resultMap 查询用户 -->
<select id="selectUser2" resultMap="usersResultMap" parameterType="int">
    select * from users where id = #{id}
</select>

dao：

Users selectUser2(Integer id);

测试：

@Test
public void test(){
    SqlSession sqlSession = MybatisUtils.getSqlSession();
    UsersDao mapper = sqlSession.getMapper(UsersDao.class);
    Users users = mapper.selectUser(1);
    sqlSession.close();
    System.out.println(users);
}
@Test
public void test2(){
    SqlSession sqlSession = MybatisUtils.getSqlSession();
    Users users = (Users) sqlSession.selectOne(
            "mybatis.dao.UsersDao.selectUser", 2
    );
    sqlSession.close();
    System.out.println(users);
}
@Test
public void test3(){
    SqlSession sqlSession = MybatisUtils.getSqlSession();
    UsersDao mapper = sqlSession.getMapper(UsersDao.class);
    Users users = mapper.selectUser2(2);
    sqlSession.close();
    System.out.println(users);
}

新增：

mapper：

<!-- 增加  -->
<insert id="insertUsers" parameterType="Users" keyProperty="id">
    insert into users(username,password,rolename,identity,mobile)
    values(#{username},#{password},#{rolename},#{identity},#{mobile})
</insert>

dao：

int insertUsers(Users users);

测试：

@Test
public void test10(){
    SqlSession sqlSession = MybatisUtils.getSqlSession();
    UsersDao mapper = sqlSession.getMapper(UsersDao.class);
    Users users=new Users("可admin444","admin444","可admin444","7","144");
    int i = mapper.insertUsers(users);
    if(i>0) System.out.println("新增成功");
    else System.out.println("新增失败");
    sqlSession.commit();
    sqlSession.close();
    System.out.println(users);
}

修改：

mapper：

<!--修改 -->
<update id="updateUsers" parameterType="Users">
    update users set password=#{password} where id=#{id}
</update>

dao：

int updateUsers(Users users);

测试：

@Test
public void test11(){
    SqlSession sqlSession = MybatisUtils.getSqlSession();
    UsersDao mapper = sqlSession.getMapper(UsersDao.class);
    Users users=new Users();
    users.setId(1);
    users.setPassword("admin666");
    int i = mapper.updateUsers(users);
    if(i>0) System.out.println("修改成功");
    else System.out.println("修改失败");
    sqlSession.commit();
    sqlSession.close();
    System.out.println(users);
}

删除：

mapper：

<!-- 删除 -->
<delete id="deleteUsers" parameterType="int">
    delete from users where id=#{id}
</delete>

dao：

int deleteUsers(Integer id);

测试：

@Test
public void test12(){
    SqlSession sqlSession = MybatisUtils.getSqlSession();
    UsersDao mapper = sqlSession.getMapper(UsersDao.class);
    int i = mapper.deleteUsers(12);
    if(i>0) System.out.println("删除成功");
    else System.out.println("删除失败");
    sqlSession.commit();
    sqlSession.close();
}