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：
...
1.8
1.3.1.Final
...
org.mapstruct
mapstruct
${mapstruct.version}
...
org.apache.maven.plugins
maven-compiler-plugin
3.8.1
${java.version}
${java.version}
org.mapstruct
mapstruct-processor
${mapstruct.version}
...
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;
}
}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 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 getImages() {
return images;
}
public void setImages(List 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 ListconvertImagesStrToList(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 ListimageList = 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。