MapStruct入门使用

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2022年09月08日 00:58 · 阅读数 291

文章目录

在实际的项目开发中会大量的使用POJO作为数据载体，通常有如下的：

实体名	实体含义	说明
DO	Data Object	与数据库表结构一一对应，通过DAO层向上传输数据源对象
DTO	Data Transfer Object	数据传输对象，Service或Manager向外传输的对象
BO	Business Object	业务对象，由Service层输出的封装业务逻辑的对象
VO	View Object	显示层对象，通常是 Web 向模板渲染引擎层传输的对象

Spring BeanUtils
Apache BeanUtils
Orika的MapperFacade和MapperFactory
MapStruct可以选择MapStruct，功能十分强大，而且很灵活，可以满足我们需要的各种需求。

入门案例

Maven项目引入

只需要在pom.xml文件中加入以下依赖即可：

...
<properties>
        <java.version>1.8</java.version>
        <mapstruct.version>1.3.1.Final</mapstruct.version>
    </properties>
...
    <dependencies>
        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct</artifactId>
            <version>${mapstruct.version}</version>
        </dependency>
    </dependencies>
...
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>${java.version}</source>
                    <target>${java.version}</target>
                    <annotationProcessorPaths>
                        <path>
                            <groupId>org.mapstruct</groupId>
                            <artifactId>mapstruct-processor</artifactId>
                            <version>${mapstruct.version}</version>
                        </path>
                    </annotationProcessorPaths>
                </configuration>
            </plugin>
        </plugins>
    </build>
...

MapStruct入门使用

package com.linfanchen.springboot.lab.mapstruct.domain;

public class CarDO { 
    /**
     * 主键ID
     */
    private Integer id;

    /**
     * 名称
     */
    private String name;

    /**
     * 品牌
     */
    private String brand;

    /**
     * 车价
     */
    private Integer price;

    /**
     * 轮胎属性
     */
    private TyreDO tyreDO;

    /**
     * 汽车图片
     */
    private String images;

    public  String  getImages()  { 
        return images;
    }

    public  void  setImages(String images)  { 
        this.images = images;
    }

    public  TyreDO  getTyreDO()  { 
        return tyreDO;
    }

    public  void  setTyreDO(TyreDO tyreDO)  { 
        this.tyreDO = tyreDO;
    }

    public  Integer  getId()  { 
        return id;
    }

    public  void  setId(Integer id)  { 
        this.id = id;
    }

    public  String  getName()  { 
        return name;
    }

    public  void  setName(String name)  { 
        this.name = name;
    }

    public  String  getBrand()  { 
        return brand;
    }

    public  void  setBrand(String brand)  { 
        this.brand = brand;
    }

    public  Integer  getPrice()  { 
        return price;
    }

    public  void  setPrice(Integer price)  { 
        this.price = price;
    }
}</pre>

<pre class="prettyprint hljs cs">package com.linfanchen.springboot.lab.mapstruct.domain;

/**
 * 轮胎
 */
public class TyreDO { 
    /**
     * 主键ID
     */
    private Integer id;

    /**
     * 轮胎名称
     */
    private String name;

    /**
     * 轮胎尺寸
     */
    private Integer size;

    public  Integer  getId()  { 
        return id;
    }

    public  void  setId(Integer id)  { 
        this.id = id;
    }

    public  String  getName()  { 
        return name;
    }

    public  void  setName(String name)  { 
        this.name = name;
    }

    public  Integer  getSize()  { 
        return size;
    }

    public  void  setSize(Integer size)  { 
        this.size = size;
    }
}

目标对象

package com.linfanchen.springboot.lab.mapstruct.bo;

import com.linfanchen.springboot.lab.mapstruct.domain.TyreDO;

import java.util.List;

/**
 * 汽车业务对象
 */
public class CarBO { 
    /**
     * 主键ID
     */
    private Integer id;

    /**
     * 名称
     */
    private String name;

    /**
     * 品牌
     */
    private String brand;

    /**
     * 车价
     */
    private Integer price;

    /**
     * 轮胎属性
     */
    private TyreDO tyreDO;

    /**
     * 汽车图片
     */
    private String images;

    public  Integer  getId()  { 
        return id;
    }

    public  void  setId(Integer id)  { 
        this.id = id;
    }

    public  String  getName()  { 
        return name;
    }

    public  void  setName(String name)  { 
        this.name = name;
    }

    public  String  getBrand()  { 
        return brand;
    }

    public  void  setBrand(String brand)  { 
        this.brand = brand;
    }

    public  Integer  getPrice()  { 
        return price;
    }

    public  void  setPrice(Integer price)  { 
        this.price = price;
    }

    public  TyreDO  getTyreDO()  { 
        return tyreDO;
    }

    public  void  setTyreDO(TyreDO tyreDO)  { 
        this.tyreDO = tyreDO;
    }

    public  String  getImages()  { 
        return images;
    }

    public  void  setImages(String images)  { 
        this.images = images;
    }
}

CarDetailBO

package com.linfanchen.springboot.lab.mapstruct.bo;

import com.linfanchen.springboot.lab.mapstruct.domain.TyreDO;

import java.util.List;

/**
 * 汽车业务对象
 */
public class CarDetailBO { 
    /**
     * 主键ID
     */
    private Integer carId;

    /**
     * 名称
     */
    private String carName;

    /**
     * 品牌
     */
    private String carBrand;

    /**
     * 车价
     */
    private Integer price;

    /**
     * 轮胎属性
     */
    private TyreDO tyreDetail;

    /**
     * 汽车图片
     */
    private List<String> images;

    public  Integer  getCarId()  { 
        return carId;
    }

    public  void  setCarId(Integer carId)  { 
        this.carId = carId;
    }

    public  String  getCarName()  { 
        return carName;
    }

    public  void  setCarName(String carName)  { 
        this.carName = carName;
    }

    public  String  getCarBrand()  { 
        return carBrand;
    }

    public  void  setCarBrand(String carBrand)  { 
        this.carBrand = carBrand;
    }

    public  Integer  getPrice()  { 
        return price;
    }

    public  void  setPrice(Integer price)  { 
        this.price = price;
    }

    public  TyreDO  getTyreDetail()  { 
        return tyreDetail;
    }

    public  void  setTyreDetail(TyreDO tyreDetail)  { 
        this.tyreDetail = tyreDetail;
    }

    public List<String> getImages() { 
        return images;
    }

    public  void  setImages(List<String> images)  { 
        this.images = images;
    }
}

转换器 CarConvert

说明：

INSTANCE 是MapStruct为我们提供的映射工厂，指定接口类型后自动帮我们创建接口的实现，且保证是线程安全的单例，无需自己手动创建。

package com.linfanchen.springboot.lab.mapstruct.convert;

import com.linfanchen.springboot.lab.mapstruct.bo.CarBO;
import com.linfanchen.springboot.lab.mapstruct.bo.CarDetailBO;
import com.linfanchen.springboot.lab.mapstruct.domain.CarDO;
import org.apache.commons.lang3.StringUtils;
import org.mapstruct.Mapper;
import org.mapstruct.Mapping;
import org.mapstruct.Mappings;
import org.mapstruct.Named;
import org.mapstruct.factory.Mappers;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 * 转换类
 */
@Mapper
public interface  CarConvert  { 

CarConvert INSTANCE = Mappers.getMapper(CarConvert.class);

/**
 * 来源和目标类的直接转换
 */
CarBO convert(CarDO carDO);

/**
 * 添加字段处理和映射关系后的转换
 */
@Mappings({ 
        @Mapping(source = "id", target = "carId"),
        @Mapping(source = "name", target = "carName"),
        @Mapping(source = "brand", target = "carBrand"),
        @Mapping(source = "tyreDO.id", target = "tyreDetail.id"),
        @Mapping(source = "tyreDO.name", target = "tyreDetail.name"),
        @Mapping(source = "tyreDO.size", target = "tyreDetail.size"),
        @Mapping(source = "images", target = "images", qualifiedByName = "convertImagesStrToList")

})
CarDetailBO convertDetail(CarDO carDO);

@Named("convertImagesStrToList")
default List<String> convertImagesStrToList(String images) { 
    String[] splitArr = org.springframework.util.StringUtils.split(images, ",");
    return new ArrayList<>(Arrays.asList(splitArr));
}

}

使用 CarTest

package com.linfanchen.springboot.lab.mapstruct;

import com.linfanchen.springboot.lab.mapstruct.bo.CarBO;
import com.linfanchen.springboot.lab.mapstruct.bo.CarDetailBO;
import com.linfanchen.springboot.lab.mapstruct.convert.CarConvert;
import com.linfanchen.springboot.lab.mapstruct.domain.CarDO;
import com.linfanchen.springboot.lab.mapstruct.domain.TyreDO;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

@RunWith(SpringRunner.class)
@SpringBootTest
public class  CarTest  { 

@Test
public void test() { 
    // 创建轮胎对象
    TyreDO tyreDO = new TyreDO();
    tyreDO.setId(888);
    tyreDO.setName("米其林245/45R19");
    tyreDO.setSize(19);

    // 汽车图片地址，通过半角逗号分隔的http地址
    List<String> imageList = new ArrayList<>();
    imageList.add("https://www.bmw.com.cn/image.1601043751651.jpg");
    imageList.add("https://www.bmw.com.cn/image.1623295725814.jpg");
    imageList.add("https://www.bmw.com.cn/image.1611042489480.jpg");
    String imageStr = imageList.stream().map(String::valueOf).collect(Collectors.joining(","));

    // 创建汽车对象
    CarDO carDO = new CarDO();
    carDO.setId(123);
    carDO.setBrand("BMW");
    carDO.setName("宝马530Li行政版");
    carDO.setPrice(540000);
    carDO.setTyreDO(tyreDO);
    carDO.setImages(imageStr);

    // 直接的数据拷贝
    CarBO carBO = CarConvert.INSTANCE.convert(carDO);
    System.out.println(carBO.getImages());
    System.out.println(carBO.getBrand());
    System.out.println(carBO.getName());
    System.out.println(carBO.getTyreDO());

    // 带数据转换的拷贝
    CarDetailBO carDetailBO = CarConvert.INSTANCE.convertDetail(carDO);
    System.out.println(carDetailBO.getImages());
    System.out.println(carDetailBO.getTyreDetail().getName());
}

}

在需要进行对象的转换的时候，我们可以使用MapStruct进行各种灵活的转换，最终得到我们想要的数据。