查询

查询全部

<!-- 查询全部 -->
<select id="queryAll" resultType="map">
  select * from teacher
</select>

@Test
public void test02(){
    SqlSession sqlSession = MybatisUtils.getSqlSession();
    //方式二：
    List<Map> objects = sqlSession.selectList("com.crud.mapper.TeacherMapper.queryAll");
    System.out.println(objects);
}

查询一条数据

<!-- 添加一个查询语句 -->
<select id="queryById" parameterType="Long" resultType="com.crud.pojo.Teacher">
  select * from teacher where teacherId = #{teacherId}
</select>

@Test
public void test01() {
    SqlSession sqlSession = MybatisUtils.getSqlSession();
    //方式一：
    TeacherMapper mapper = sqlSession.getMapper(TeacherMapper.class);
    Teacher teacher = mapper.queryById(1L);
    System.out.println(teacher);
}

查询总条数

<!-- 查询总条数 -->
<select id="queryTotal" resultType="int">
  select count(*) from teacher
</select>

@Test
public void test03(){
    SqlSession sqlSession = MybatisUtils.getSqlSession();
    Object o = sqlSession.selectOne("com.crud.mapper.TeacherMapper.queryTotal");
    System.out.println(o);
}

增删改

增删改需要手动提交事务

sqlSession.commit();

插入数据

默认返回类型int

<!-- 添加数据 -->
<insert id="saveTeacher" parameterType="com.crud.pojo.Teacher">
  insert into teacher(teacherName,loginPass,teacherGender,teacherTel,status)
  values (#{teacherName},#{loginPass},#{teacherGender},#{teacherTel},#{status})
</insert>

@Test
public void test04(){
    Teacher teacher = new Teacher("杨","123456",2,"19987483322",1);
    SqlSession sqlSession = MybatisUtils.getSqlSession();
    int insert = sqlSession.insert("com.crud.mapper.TeacherMapper.saveTeacher",teacher);
    System.out.println(insert);
    //增删改需要手动提交事务
    sqlSession.commit();
}

修改和删除同上