[游戏开发]java树形结构数据根据某个节点或多个节点返回所有子级ID(包含本身)

dictCode parentCode是父子级关系，可以对应修改成id和parentId

树形工具类 TreeUtil.java

import com.bmsoft.voice.entity.dto.TreeDTO;

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

/**
 * @author 23Legend
 */
public class TreeUtil {

    /**
     * 使用递归方法建树
     * @param list
     * @return
     */
    public static <T extends TreeDTO> List<T> buildByRecursive(List<T> list) {
        List<T> trees = new ArrayList<T>();
        for (T t : list) {
            if (null == t.getParentCode()) {
                trees.add(findChildren(t, list));
            }
        }
        return trees;
    }

    /**
     * 递归查找子节点
     * @param list
     * @return
     */
    public static <T extends TreeDTO> T findChildren(T root, List<T> list) {
        root.setChildren(new ArrayList<T>());
        for (T it : list) {
            if (root.getDictCode().equals(it.getParentCode())) {
                if (root.getChildren() == null) {
                    root.setChildren(new ArrayList<T>());
                }
                root.getChildren().add(findChildren(it, list));
            }
        }
        return root;
    }

    public static <T extends TreeDTO> List<T> getTress(List<T> root) {
        for (int i = 0; i < root.size(); i++) {
            // 查询某节点的子节点（获取的是list）
            List<T> children = new ArrayList<T>();
            if (null != root.get(i).getChildren()) {
                children = root.get(i).getChildren();
            }
            getTress(children);
        }
        return root;
    }

    public static <T extends TreeDTO> List<T> getByParent(List<T> list,String pid) throws Exception{
        List<T> childList = new ArrayList<T>();
        for (T item : list) {
            if (item != null) {
                // 判断当前节点的父节点是不是pid
                if (pid.equals(item.getParentCode())) {
                    List<T> child = getByParent(list, item.getDictCode());
                    item.setChildren(child);
                    childList.add(item);
                }
            }
        }
        return getTress(childList);
    }

    public static <T extends TreeDTO> List<String> getCodes(List<T> root, List<String> result){
        for (int i = 0; i < root.size(); i++) {
            // 查询某节点的子节点（获取的是list） 前序遍历
            result.add(root.get(i).getDictCode());
            if (null != root.get(i).getChildren()) {
                List<T> children = root.get(i).getChildren();
                getCodes(children,result);
            }
            //result.add(root.get(i).getId());//后序遍历
        }
        return result;
    }
}

树形数据继承 TreeDTO.java (swagger相关可以去除)

import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;

import java.util.List;

/**
* @author 23Legend
*/
@Data
@ApiModel("树形数据公共类")
public class TreeDTO<T> {
    @ApiModelProperty(value = "ID")
    private Long id;
    @ApiModelProperty(value = "code")
    private String dictCode;
    @ApiModelProperty("父级code")
    private String parentCode;
    @ApiModelProperty("子级集")
    private List<T> children;
}

使用

// 封装层级以及层级的作有子级code
        List<String> codes = Lists.newArrayList();
        if (Optional.ofNullable(request.getPages()).isPresent() && !request.getPages().isEmpty()) {
            List<SysDictDTO> list = transform2DTO();
            request.getPages().stream().forEach(item -> {
                try {
                    List<SysDictDTO> byParent = TreeUtil.getByParent(list, item);
                    if (null != byParent && !byParent.isEmpty()){
                        TreeUtil.getCodes(byParent, codes);
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            });
            codes.addAll(request.getPages());
        }

注意继承类：?

@Data
@ApiModel(value = "字典传输对象")
public class SysDictDTO extends TreeDTO{}

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