1. 程式人生 > >Mybatis框架實體類欄位與資料庫表字段不一致導致查詢該欄位的值一直為null

Mybatis框架實體類欄位與資料庫表字段不一致導致查詢該欄位的值一直為null

實體類如下所示:

public class BasicInfo {
    private Integer basic_id;
    private String name;
    private String gender;
    private Integer age;
    private String address;
    private String email;
    private String phone;
    private String school;
    private String introduce;

    //……(此處省略setter和getter方法)
}

實體類對映的資料庫表如下所示:

create table `basic_info`
 (
      `basic_id` int not null auto_increment,
      `name` varchar(16),
      `gender` varchar(4) ,
      `age` int default '0',
      `address` varchar(64),
      `email` varchar(32),
      `tel` varchar(16),
      `school` varchar(64),
      `introdece`
varchar(1024), `user_id` int, primary key (`basic_id`), key `fk_basicinfo_account` (`user_id`), constraint `fk_basicinfo_account` foreign key (`user_id`) references `account` (`id`) ) engine=InnoDB default charset=utf8 |

使用Mybatis查詢配置如下所示

<select id="queryById" parameterType="int"
resultType="BasicInfo">
select basic_id,name,gender, age,school,tel from basic_info where basic_id = #{id} </select>

主要查詢java程式碼:

@Override
    public BasicInfo queryById(Integer id) {
        BasicInfo basicInfo = null;
        SqlSession session = MybatisSessionManage.getSqlSessionAutoCommit();
        basicInfo = session.selectOne("basicinfo.queryById", id);
        return basicInfo;
    }

查詢結果:

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解決方法

方法1
查詢中含有表字段與物件欄位不對應的,可以在查詢語句用as 物件欄位名解決欄位不一致不自動封裝的問題

<select id="queryById" parameterType="int" resultType="BasicInfo">
        select basic_id,name,gender, age,school,tel as phone
        from basic_info
        where basic_id = #{id}
</select>

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方法2
修改select元素中resultType屬性 為 resultMap屬性並建立返回的map型別

<resultMap id="basicInfoMapper" type="BasicInfo">
        <id column="basic_info" property="basic_id" />
        <result column="name" property="name" />
        <result column="gender" property="gender" />
        <result column="age" property="age" />
        <result column="address" property="address" />
        <result column="email" property="email" />
        <result column="tel" property="phone" />
        <result column="school" property="school" />
        <result column="introduce" property="introduce" />
</resultMap>

<select id="queryByIdAndMapper"  resultMap="basicInfoMapper" parameterType="int">
        select basic_id,name,gender, age,school,tel
        from basic_info
        where basic_id = #{id}
</select>

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執行結果:
這裡寫圖片描述