java - 构造resultMap为同一个集合创建不同的实例

Question

(使用 MyBatis v3.0.4。)我有一个问题，我不知道如何解决。我的对象模型是:

位置.java

public class Location {
    // ... other content
    private List addresses; 
    // ... other content
}

地址.java

public class Address { 
    public enum Type { POSTAL, POBOX, INPUT, CLEANSED } 
    private Type type; 
    private String line1; 
    // ... other content
}

我的 SQL 是:

SELECT 
    // ... other content 
    postal_address_line_1, 
    postal_address_line_2, 
    postal_address_city, 
    cleansed_address_line_1, 
    cleansed_address_line_2, 
    cleansed_address_city, 
    // ... other content

我将如何构造一个 resultMap 来插入适当的列到正确类型的地址实例中并添加到Location.java 中的相同列表？我想避免必须添加Location.java 的另一个实例变量只是为了保存不同的地址类型。

Answer 1

在结果图中使用鉴别器标签。

查看mybatis user guide .搜索“discriminator”你会看到更多信息。

<resultMap id="vehicleResult" type="Vehicle">
   <id property=”id” column="id" />
   <result property="sharedPropA" column="shared_column"/>
   <discriminator javaType="int" column="address_type">
     <case value="1" resultMap="postalResultMap"/>
     <case value="2" resultMap="inputResultMap"/>
     <case value="3" resultMap="cleanResultMap"/>
     <case value="4" resultMap="whatIsaCleansedAddressResultMap"/>
   </discriminator>
</resultMap>

补充 1:

您需要将地址选择为不同的行。

即

select
    postal_address_line_1 as line1, 
    postal_address_line_2 as line2, 
    postal_address_city as city,
    type as 'POSTAL'

....

联盟

select
    postal_address_line_1 as line1, 
    postal_address_line_2 as line2, 
    postal_address_city as city,
    type as 'CLEANSED'

.....

然后内置枚举类型处理程序应该正确设置类型。