MyBatis（三）MyBatis的增删改查

（1）接口中编写方法

    public Emp getEmp(Integer id);
    
    public void addEmp(Emp emp);
    
    public void deleteEmp(Integer id);
    
    public void updateEmp(Emp emp);

 （2）编写Mapper文件

<select id="getEmp" resultType="com.eu.bean.Emp">
    select id,last_name lastName,gender,email from Emp where id = #{id}
  </select>
 
  <!-- 最后两个属性为获取自增主键的值 如果不需要获取则可以省去 -->
  <insert id="addEmp" parameterType="com.eu.bean.Emp" useGeneratedKeys="true" keyProperty="id">
      INSERT INTO emp(last_name,gender,email) 
      VALUES(#{lastName},#{geder},#{email})
  </insert>
  
  <update id="updateEmp" parameterType="com.eu.bean.Emp">
       update emp
       set last_name = #{lastName},
               gender = #{geder},
               email = #{email}
       where id = #{id}
  </update>
  
  <delete id="deleteEmp">
      delete from emp where id=#{id}
  </delete>

（3）编写测试

public SqlSessionFactory getSqlSessionFactory() throws IOException {
        String resource = "conf/mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        return new SqlSessionFactoryBuilder().build(inputStream);
    }
    
    @Test
    public void testMapper() throws IOException {
        SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
        //1.获取到sqlsession 不会自动提交数据
        SqlSession openSession = sqlSessionFactory.openSession();
        EmpDao mapper = openSession.getMapper(EmpDao.class);
        
        //测试添加

        Emp emp = new Emp(null, "李四", "男","www.com"); 
        mapper.addEmp(emp);
        System.out.println(emp.getId());
        //测试修改
        /*
         * Emp emp2 = new Emp(3, "李四", "wu", "666333"); mapper.updateEmp(emp2);
         */
        
        //测试删除
        //mapper.deleteEmp(3);
        //手动提交数据
        openSession.commit();
        openSession.close();
    }