MapStruct解决嵌套对象的问题

这几天项目用了一下MapStruct，真是太好用了，相见恨晚啊！真乃开发神器！码农福音！在引强烈推荐一下！
MapStruct可以替代传统的getter和setter方法的转换，并且效率相当，同时省去了手写转换方法的过程，极大提高了开发效率！（省的时间可以。。。嗯。。。你们懂的）

如果是两个简单对象（没有属性为对象的类）可以直接转换，属性名不相同的，可以用@Mappings转换，具体可以参考下面的例子。

废话少说，上代码

1、引入依赖：

  

    1.5.0.RC1
    0.2.0
  


      org.mapstruct
      mapstruct
      ${org.mapstruct.version}



    
      
        org.apache.maven.plugins
        maven-compiler-plugin
        3.8.1
        
          ${java.version}
          ${java.version}
          
            
              org.mapstruct
              mapstruct-processor
              ${org.mapstruct.version}
            
            
              org.projectlombok
              lombok
              ${lombok.version}
            
            
              org.projectlombok
              lombok-mapstruct-binding
              
              ${lombok-mapstruct-binding.version}
            
          
        
      
    
  

 2、测试目标类（需要转换的结果对象）

import java.util.List;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

/**
 * @author zhuo yan
 * @created 2022-06-02 15:04:44
 **/
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Target {

  private String id;
  private String username;
  private String cname;
  private List menus;

  @Data
  @AllArgsConstructor
  @NoArgsConstructor
  public static class SubBeanInTarget {

    private int id;
    private String title;
    private String icon;
    private List children;


    @Data
    @AllArgsConstructor
    @NoArgsConstructor
    public static class ChildrenTarget {

      private int id;
      private String title;
      private String path;
    }
  }
}

3、数据来源对象

import java.io.Serializable;
import java.util.List;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.EqualsAndHashCode;
import lombok.NoArgsConstructor;

/**
 * @author zhuo yan
 * @created 2022-06-02 15:06:38
 **/

@Data
@EqualsAndHashCode(callSuper = false)
public class Resource implements Serializable {
  private static final long serialVersionUID = 1L;
  private Long permId;
  private String permName;
  private String permPath;
  private List menuList;

  @Data
  @AllArgsConstructor
  @NoArgsConstructor
  public static class SubBeanInResource {

    private int subBeanId;
    private String titleName;
    private String iconName;
    private List childrenList;

    @Data
    @AllArgsConstructor
    @NoArgsConstructor
    public static class ChildrenResource {

      private int childId;
      private String childName;
      private String pathName;
    }
  }
}

3、转换工具类

import com.znlh.gyl.warehouse.web.convertor.test.Resource.SubBeanInResource;
import com.znlh.gyl.warehouse.web.convertor.test.Resource.SubBeanInResource.ChildrenResource;
import com.znlh.gyl.warehouse.web.convertor.test.Target.SubBeanInTarget;
import com.znlh.gyl.warehouse.web.convertor.test.Target.SubBeanInTarget.ChildrenTarget;
import java.util.List;
import org.mapstruct.Mapper;
import org.mapstruct.Mapping;
import org.mapstruct.Mappings;

/**
 * @author zhuo yan
 * @created 2022-06-02 15:08:31
 **/
@Mapper(componentModel = "spring")
public interface MyConverter {

  @Mappings({
      @Mapping(source = "permId", target = "id"),
      @Mapping(source = "menuList", target = "menus")
  })
  Target convert(Resource perm);

  // 下面的几个方法可以辅助完成上面的那个 Target 转换而写的,在convert方法调用时,会自动调用对象中所嵌套的子对象的转换方法
  List convertBeanList(List userP);

  @Mappings({
      @Mapping(source = "subBeanId", target = "id"),
      @Mapping(source = "titleName", target = "title"),
      @Mapping(source = "iconName", target = "icon"),
      @Mapping(source = "childrenList", target = "children")
  })
  SubBeanInTarget convertSubBean(SubBeanInResource userPerm);

  List convertChildrenList(List perms);

  @Mappings({
      @Mapping(source = "childId", target = "id"),
      @Mapping(source = "childName", target = "title"),
      @Mapping(source = "pathName", target = "path")
  })
  ChildrenTarget convertChildren(ChildrenResource perm);

}

 4、查看MapStruct自动帮我们生成的类：

import java.util.ArrayList;
import java.util.List;
import javax.annotation.processing.Generated;
import org.springframework.stereotype.Component;

@Generated(
    value = "org.mapstruct.ap.MappingProcessor",
    date = "2022-06-02T16:45:57+0800",
    comments = "version: 1.5.0.RC1, compiler: javac, environment: Java 11.0.15.1 (Oracle Corporation)"
)
@Component
public class MyConverterImpl implements MyConverter {

    @Override
    public Target convert(Resource perm) {
        if ( perm == null ) {
            return null;
        }

        Target target = new Target();

        if ( perm.getPermId() != null ) {
            target.setId( String.valueOf( perm.getPermId() ) );
        }
        target.setMenus( convertBeanList( perm.getMenuList() ) );

        return target;
    }

    @Override
    public List convertBeanList(List userP) {
        if ( userP == null ) {
            return null;
        }

        List list = new ArrayList( userP.size() );
        for ( Resource.SubBeanInResource subBeanInResource : userP ) {
            list.add( convertSubBean( subBeanInResource ) );
        }

        return list;
    }

    @Override
    public Target.SubBeanInTarget convertSubBean(Resource.SubBeanInResource userPerm) {
        if ( userPerm == null ) {
            return null;
        }

        Target.SubBeanInTarget subBeanInTarget = new Target.SubBeanInTarget();

        subBeanInTarget.setId( userPerm.getSubBeanId() );
        subBeanInTarget.setTitle( userPerm.getTitleName() );
        subBeanInTarget.setIcon( userPerm.getIconName() );
        subBeanInTarget.setChildren( convertChildrenList( userPerm.getChildrenList() ) );

        return subBeanInTarget;
    }

    @Override
    public List convertChildrenList(List perms) {
        if ( perms == null ) {
            return null;
        }

        List list = new ArrayList( perms.size() );
        for ( Resource.SubBeanInResource.ChildrenResource childrenResource : perms ) {
            list.add( convertChildren( childrenResource ) );
        }

        return list;
    }

    @Override
    public Target.SubBeanInTarget.ChildrenTarget convertChildren(Resource.SubBeanInResource.ChildrenResource perm) {
        if ( perm == null ) {
            return null;
        }

        Target.SubBeanInTarget.ChildrenTarget childrenTarget = new Target.SubBeanInTarget.ChildrenTarget();

        childrenTarget.setId( perm.getChildId() );
        childrenTarget.setTitle( perm.getChildName() );
        childrenTarget.setPath( perm.getPathName() );

        return childrenTarget;
    }
}

 大功告成！实际上我们的开发代码只有一个MyConverter！嗯，真香！