Javaweb -- MyBatis 添加、删除、参数传递，注解调用

Javaweb – MyBatis

添加操作

// mapper
void add(Brand brand);
//BrandMapper.xml
<insert id="add" >
        insert into tb_brand(brand_name, company_name, ordered, description, status)
        values (#{brandName}, #{companyName}, #{ordered}, #{description}, #{status})
        ;
    </insert>
//Test
  // 封装对象
        Brand brand = new Brand();
        brand.setStatus(status);
        brand.setCompanyName(companyName);
        brand.setBrandName(brandName);
        brand.setDescription(description);
        brand.setOrdered(ordered);
mapper.add(brand);
        // 提交事务
        sqlSession.commit();

因为这里数据库中的事务未设置自动提交所以会自动回滚，需要i自己手动提交事务。

// 设置自动提交事务或者手动提交事务 false为手动提交事务
SqlSession sqlSession = sessionFactory.openSession(true);

添加 – 主键返回

<insert id="add" useGeneratedKeys="true" keyProperty="id">
    insert into tb_brand(brand_name, company_name, ordered, description, status)
    values (#{brandName}, #{companyName}, #{ordered}, #{description}, #{status})
    ;
</insert>
System.out.println(brand.getId());

修改

1. 修改全部字段
2. <update id="update">
        update tb_brand
        set brand_name   = #{brandName},
            company_name = #{companyName},
            ordered      = #{ordered},
            description  = #{description},
            status       = #{status}
        where
            id = #{id};
    </update>

 int update = mapper.update(brand);
        System.out.println(update);

3. 2.修改部分字段
   因为存在逗号以及可能修改的值为null所以需要采用set字段

</update>
    <update id="updatesingle">
        update tb_brand
        set
        <if test="brandName != null and brandName != ''">
            brand_name = #{brandName},
        </if>
        <if test="companyName != null and companyName != ''">
            company_name = #{companyName},
        </if>
        <if test="description != null and description != ''">
            description = #{description},
        </if>
        <if test="ordered != null and ordered != ''">
            ordered = #{ordered},
        </if>
        <if test="status != null and status != ''">
            status = #{status}
        </if>
        where
        id = #{id};
    </update>

删除单个

//mapper
    void deleteById(int id);
    //BrandMapper.xml
      <delete id="deleteById">
        delete
        from tb_brand
        where id = #{id};
    </delete>
    <delete id="deleteMulti">
        delete
        from tb_brand
        where id
        in
        <foreach collection="ids" item="id" separator="," open="(" close=")">
            #{id}
        </foreach>
        ;
    </delete>

批量删除

//mapper
  void deleteMulti(@Param("ids") int[] ids);
      //BrandMapper.xml
    <delete id="deleteMulti">
        delete
        from tb_brand
        where id
        in
        <foreach collection="ids" item="id" separator="," open="(" close=")">
            #{id}
        </foreach>
        ;
    </delete>

删除时需要进行备注默认为collection 里面传入数组默认为array 可以使用注解@param(" ")设置姓名

参数传递问题

MyBatis对参数的封装

注： 不要使用默认名称 使用@Param注解即可

注解形式（适合简单代码）

 @Delete("delete from tb_user where id = #{id}")
    void deleteById(int id);

直接调用即可