在mapstruct中使用spring中的bean进行复杂逻辑转换

映射对象

package example.model;

import lombok.Data;

@Data
public class Source {
	private Integer gender;

}

package example.model;

import lombok.Data;

@Data
public class Target {
	private String gender;

}

Spring中的bean

package example.component;

import org.springframework.stereotype.Component;

@Component
public class SomeComponent {

	public void doSomething() {

	}

}

开始写Mapper

创建Mapper接口

创建Mapper接口，但是建议不要急于引入mapstruct注解，想加也可以，反正等下都要回来改

package example.mapper;

import example.model.Source;
import example.model.Target;

public interface DecoratorMapper {

	Target sourceToTarget(Source source);

}

创建Mapper的修饰器

这是一个抽象类，实现Mapper接口，并重写需要使用Spring中bean的方法，要特别注意的是修饰器里面装配的Mapper属性必须指明bean名称为delegate，在修饰器中实现调用其他bean等复杂逻辑即可

package example.mapper;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;

import example.component.SomeComponent;
import example.model.Source;
import example.model.Target;

public abstract class DecoratorMapperDecorator implements DecoratorMapper {

	@Autowired
	private SomeComponent someComponent;

	@Autowired
	@Qualifier("delegate") //必须叫这个名字，mapstruct默认的不能改
	private DecoratorMapper decoratorMapper;

	@Override
	public Target sourceToTarget(Source source) {
		Target target = decoratorMapper.sourceToTarget(source);
		someComponent.doSomething();
		return target;
	}

}

在Mapper接口指定修饰器

现在回来修改Mapper接口，对修饰器进行指定

package example.mapper;

import org.mapstruct.DecoratedWith;
import org.mapstruct.Mapper;

import example.model.Source;
import example.model.Target;

@Mapper(componentModel = "spring")
@DecoratedWith(DecoratorMapperDecorator.class)
public interface DecoratorMapper {

	Target sourceToTarget(Source source);

}

编译产物

默认实现

mapstruct默认的实现，唯一的不同就是多了个Qualifier命名

package example.mapper;

import example.model.Source;
import example.model.Target;
import javax.annotation.Generated;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Component;

@Generated(
    value = "org.mapstruct.ap.MappingProcessor",
    date = "2023-01-29T17:11:04+0800",
    comments = "version: 1.5.3.Final, compiler: Eclipse JDT (IDE) 1.4.300.v20221108-0856, environment: Java 17.0.3 (Eclipse Adoptium)"
)
@Component
@Qualifier("delegate")
public class DecoratorMapperImpl_ implements DecoratorMapper {

    @Override
    public Target sourceToTarget(Source source) {
        if ( source == null ) {
            return null;
        }

        Target target = new Target();

        if ( source.getGender() != null ) {
            target.setGender( String.valueOf( source.getGender() ) );
        }

        return target;
    }
}

修饰器实现

修饰器是个抽象类，所以mapstruct会生成一个对应的实现，并且作为主实现类注入到spring

package example.mapper;

import javax.annotation.Generated;
import org.springframework.context.annotation.Primary;
import org.springframework.stereotype.Component;

@Generated(
    value = "org.mapstruct.ap.MappingProcessor",
    date = "2023-01-29T17:11:04+0800",
    comments = "version: 1.5.3.Final, compiler: Eclipse JDT (IDE) 1.4.300.v20221108-0856, environment: Java 17.0.3 (Eclipse Adoptium)"
)
@Component
@Primary
public class DecoratorMapperImpl extends DecoratorMapperDecorator {
}

调用逻辑

在spring中使用Mapper进行对象转换时，调用逻辑如下：