Java工具类 - 将List转换为树状结构 java

import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.function.BiConsumer;
import java.util.function.Function;
import java.util.function.Supplier;
import java.util.stream.Collectors;
/**

@program: myUtil
@description: 工具类 - 树状结构生成
@author: syf
@create: 2021-06-15 10:38
*/

public class TreeModel {

/** * 上级字段名称 */ private Function superColumn; /** * 当前比对字段 */ private Function column; /** * 列表接收字段名 */ private BiConsumer> children; /** * 数据列表 */ private List list; /** * 数据解除关联性使用的对象 */ private Supplier decoupling; /** * 私有化工具类 */ private TreeModel() { } /** * 初始化载入树状工具类 * * @param list需要整合的数据列表 * @param superColumn 上级字段(对象::字段get方法) * @param column本级字段(对象::字段get方法) * @param children下级数据存储字段(对象::字段set方法) * @return 树状工具类 */ public static TreeModel load(List list, Function superColumn, Function column, BiConsumer> children) { TreeModel treeModel = new TreeModel<>(); treeModel.setSuperColumn(superColumn) .setColumn(column) .setChildren(children) .setList(list); return treeModel; } /** * 获取树状数据（不解除原集合中对象与树状集合对象的关联） * * @param initValue 根数据 * @return 树状数据数据列表 */ public List getTree(Object initValue) { List tree = treeAll(initValue); if (tree != null && tree.size() > 0) { return tree.stream().filter(ls -> initValue.equals(superColumn.apply(ls))).collect(Collectors.toList()); } return tree; } /** * 获取树状数据（解除原集合中对象与树状集合对象的关联） * * @param initValue根数据 * @param decoupling 解除关联对象（对象::new） * @return 树状数据数据列表 */ public List getTree(Object initValue, Supplier decoupling) { this.setDecoupling(decoupling); return tree(initValue); } /** * 获取树状数据 * * @param initValue 根数据 * @return 树状数据 */ private List treeAll(Object initValue) { if (list == null || list.size() < 1) { return list; } List collect = list.stream().filter(f -> initValue.equals(superColumn.apply(f))).collect(Collectors.toList()); if (collect.size() < 1) { return null; } collect.forEach(c -> children.accept(c, treeAll(column.apply(c)))); return collect; } private List tree(Object o) { List childrenList = new ArrayList<>(); if(o == null){ return childrenList; } for (T entity : list) { if (o.equals(superColumn.apply(entity))) { T now = decoupling.get(); copy(entity, now); childrenList.add(now); } } for (T cs : childrenList) { children.accept(cs, tree(column.apply(cs))); } return childrenList; } /** * 将source中的属性赋值给target * @param source数据来源类 * @param target数据接收类 */ private void copy(T source, T target) { if (source == null) { throw new NullPointerException("dataSource"); } if (target == null) { target = decoupling.get(); } Field[] sourceFields = source.getClass().getDeclaredFields(); Field[] targetFields =[期货](https://www.gendan5.com/p/2021-06-11/248014.html) target.getClass().getDeclaredFields(); Map sourceMap = new HashMap<>(sourceFields.length); try { for (Field field : sourceFields) { if (Modifier.isFinal(field.getModifiers())) { continue; } field.setAccessible(true); sourceMap.put(field.getName(), field.get(source)); } for (Field field : targetFields) { Object o = sourceMap.get(field.getName()); if (o == null) { continue; } field.setAccessible(true); field.set(target, o); } } catch (IllegalAccessException e) { e.printStackTrace(); } } private TreeModel setSuperColumn(Function superColumn) { if (superColumn == null) { throw new NullPointerException("superColumn"); } this.superColumn = superColumn; return this; } private TreeModel setColumn(Function column) { if (column == null) { throw new NullPointerException("column"); } this.column = column; return this; } private TreeModel setChildren(BiConsumer> children) { if (children == null) { throw new NullPointerException("children"); } this.children = children; return this; } private void setList(List list) { if (list == null || list.size() < 1) { throw new NullPointerException("list"); } this.list = list; } private void setDecoupling(Supplier decoupling) { if (decoupling == null) { throw new NullPointerException("decoupling"); } this.decoupling = decoupling; }