List数据按照树状结构(tree)进行排序

一般应用我们都是把数据直接转成树状结构。这个可以通过sql实现，但是也有用到只按照树状结构排序的情况。（适用于网站栏目设置，并且可以排序这样的功能）

以下代码是整理自网上的，以供参考：

1、一个Bean，用于模仿我们平时接收数据的实体类

public class MyTestTree {	PRivate int id;	private String name;	private int parentId;		private int no_order;	private List<MyTestTree> childrens;	public MyTestTree(int id, String name, int parentId,int no_order) {		this.id = id;		this.name = name;		this.parentId = parentId;		this.no_order = no_order;	}	public int getId() {		return id;	}	public void setId(int id) {		this.id = id;	}	public String getName() {		return name;	}	public void setName(String name) {		this.name = name;	}	public int getParentId() {		return parentId;	}	public void setParentId(int parentId) {		this.parentId = parentId;	}	public List<MyTestTree> getChildrens() {		return childrens;	}	public void setChildrens(List<MyTestTree> childrens) {		this.childrens = childrens;	}	public int getNo_order() {		return no_order;	}	public void setNo_order(int no_order) {		this.no_order = no_order;	}}2、使用测试数据进行排序
public class TestListTree {	public static void main(String[] args) {		// id,pid(父节点),name(节点名称),sequence(同级节点排序依据)		MyTestTree tree1 = new MyTestTree(1, "顶层节点1", 0, 1);		MyTestTree tree2 = new MyTestTree(2, "顶层节点2", 0, 2);		MyTestTree tree3 = new MyTestTree(3, "顶层节点3", 0, 3);		MyTestTree tree4 = new MyTestTree(4, "二级节点4", 1, 1);		MyTestTree tree5 = new MyTestTree(5, "二级节点5", 2, 2);		MyTestTree tree6 = new MyTestTree(6, "二级节点6", 3, 3);		MyTestTree tree7 = new MyTestTree(7, "三级节点7", 4, 1);		MyTestTree tree8 = new MyTestTree(8, "三级节点8", 4, 2);		MyTestTree tree9 = new MyTestTree(9, "三级节点9", 5, 1);		List<MyTestTree> list = new ArrayList<MyTestTree>();		list.add(tree1);		list.add(tree2);		list.add(tree3);		list.add(tree4);		list.add(tree5);		list.add(tree6);		list.add(tree7);		list.add(tree8);		list.add(tree9);		LinkedList<MyTestTree> result = new LinkedList<MyTestTree>();		LinkedList<MyTestTree> f = toSort(list, result, 0);		for (int i = 0; i < f.size(); i++) {			System.out.print(f.get(i).getId() + ",");			System.out.print(f.get(i).getName() + ",");			System.out.print(f.get(i).getParentId() + ",");			System.out.println(f.get(i).getNo_order());		}	}		/**	 * 	 * @Description: 排序	 * @param list	 * @param result	 * @param father	 * @return	 * LinkedList<MyTestTree>	 */	private static LinkedList<MyTestTree> toSort(List<MyTestTree> list,			LinkedList<MyTestTree> result, int father) {		List<MyTestTree> temp = new ArrayList<MyTestTree>();		// 最高层,临时存放		for (int i = 0; i < list.size(); i++) {			if (list.get(i).getParentId() == father) {				temp.add(list.get(i));			}		}		if (temp.size() < 1) {			return result;		} else { 			// 删除最高层			for (int j = 0; j < list.size(); j++) {				if (list.get(j).getParentId() == father) {					list.remove(j);				}			}			// 对最高层排序			for (int i = 0; i < temp.size() - 1; i++) {				for (int j = i + 1; j < temp.size(); j++) {					if (temp.get(i).getNo_order() > temp.get(j).getNo_order()) {						MyTestTree myTestTree = temp.get(i);						temp.set(i, temp.get(j));						temp.set(j, myTestTree);					}				}			}			// 递归			for (int i = 0; i < temp.size(); i++) {				result.add(temp.get(i));				toSort(list, result, temp.get(i).getId());			}			return result;		}	}}