树的实体类以及基于列表构建树

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**
 * @description 树实体类
 * @author yanpeng
 * @date 2021-3-17
 */
@Data
@Accessors(chain = true)
public class Tree<T> {

    private String key;

    private String id;

    private String value;

    private String code;
    /**
     * 显示节点文本
     */
    private String name;

    private String title;

    private boolean spread;

    /**
     * 节点是否被选中 true false
     */
    private boolean checked = false;

    /**
     * 创建人用户名
     */
    private String createUserName;

    /**
     * 创建时间
     */
    private Date createTime;

    /**
     * 节点属性
     */
    private Map<String, Object> attributes;

    /**
     * 节点的子节点
     */
    private List<Tree<T>> children = new ArrayList<Tree<T>>();

    /**
     * 父ID
     */
    private String parentId;
    /**
     * 是否有父节点
     */
    private boolean hasParent = false;
    /**
     * 是否有子节点
     */
    private boolean hasChildren = false;


    public Tree(String id, String name, Map<String, Object> state, boolean checked, Map<String, Object> attributes,
                List<Tree<T>> children, boolean isParent, boolean isChildren, String parentID) {
        super();
        this.id = id;
        this.name = name;
        this.checked = checked;
        this.attributes = attributes;
        this.children = children;
        this.hasParent = isParent;
        this.hasChildren = isChildren;
        this.parentId = parentID;
    }

    public Tree() {
        super();
    }

    @Override
    public String toString() {

        return JSON.toJSONString(this);
    }
}

public class BuildTree {

    public static <T> Tree<T> build(List<Tree<T>> nodes, boolean... isck) {
        if (nodes == null) {
            return null;
        }
        List<Tree<T>> topNodes = new ArrayList<Tree<T>>();
        for (Tree<T> children : nodes) {
            String pid = children.getParentId();
            if (pid == null || "0".equals(pid)) {
                topNodes.add(children);
                continue;
            }
            for (Tree<T> parent : nodes) {
                String id = parent.getId();
                if (id != null && id.equals(pid)) {
                    parent.getChildren().add(children);
                    children.setHasParent(true);
                    parent.setHasChildren(true);
                    continue;
                }
            }

        }
        Tree<T> root = new Tree<T>();
        if (topNodes.size() == 1) {
            root = topNodes.get(0);
        } else {
            root.setId("-1");
            root.setParentId("0");
            root.setHasParent(false);
            root.setHasChildren(true);
            root.setChildren(topNodes);
            root.setName("全 部");
            if (isck.length > 0 && isck[0]) {
                root.setChecked(true);
            }
        }
        return root;
    }

    public static <T> Tree<T> buildAny(List<Tree<T>> nodes) {
        if (nodes == null) {
            return null;
        }
        List<Tree<T>> topNodes = new ArrayList<Tree<T>>();
        for (Tree<T> children : nodes) {
            boolean flag = true;
            String pid = children.getParentId();
            for (Tree<T> parent : nodes) {
                String id = parent.getId();
                if (id != null && id.equals(pid)) {
                    parent.getChildren().add(children);
                    children.setHasParent(true);
                    parent.setHasChildren(true);
                    flag = false;
                    topNodes.add(children);
                    continue;
                }
            }
            if(flag){
                topNodes.add(children);
            }
        }
        Tree<T> root = new Tree<T>();
        if (topNodes.size() == 1) {
            root = topNodes.get(0);
        } else {
            root.setId("-1");
            root.setParentId("0");
            root.setHasParent(false);
            root.setHasChildren(true);
            root.setChildren(topNodes);
            root.setName("全 部");
        }
        return root;
    }

    public static <T> List<Tree<T>> buildList(List<Tree<T>> nodes, String idParam) {
        if (nodes == null) {
            return null;
        }
        List<Tree<T>> topNodes = new ArrayList<Tree<T>>();
        for (Tree<T> children : nodes) {
            String pid = children.getParentId();
            if (pid == null || idParam.equals(pid)) {
                topNodes.add(children);
                continue;
            }
            for (Tree<T> parent : nodes) {
                String id = parent.getId();
                if (id != null && id.equals(pid)) {
                    parent.getChildren().add(children);
                    children.setHasParent(true);
                    parent.setHasChildren(true);
                    continue;
                }
            }
        }
        return topNodes;
    }
}