public interface TreeNode {
String getId();
String getpId();
List getChildren();
}
public class TreeBuilder {
/**
* @param nodes 需要构建的nodes,不要继承 TreeNode,且需要有 TreeNode 下的三个方法
* @param pId 父id。为null则是所有pid为null的是顶级节点;不为null,则是从给的pId往下查询并构建树
**/
public static List buildTree(List nodes, String pId) {
List roots = new ArrayList();
for (T node : nodes) {
if (node.getId().equals(pId) || (node.getParentId() == null && (pId == null || pId.equals(node.getId())))) {
roots.add(node);
}
}
for (T root : roots) {
buildChildren(root, nodes);
}
return roots;
}
private static void buildChildren(T node, List nodes) {
for (T child : nodes) {
if (child.getParentId() != null && child.getParentId().equals(node.getId())) {
node.getChildren().add(child);
buildChildren(child, nodes);
}
}
}
}
public class TreeBuilder {
/**
* @param level 级别 从1开始。1是最顶层
**/
public static List buildTree(List nodes, String pId, int level) {
List roots = new ArrayList();
for (T node : nodes) {
if (node.getId().equals(pId) || (node.getParentId() == null && (pId == null || pId.equals(node.getId())))) {
roots.add(node);
}
}
for (T root : roots) {
buildChildren(root, nodes, level, 1);
}
return roots;
}
private static void buildChildren(T node, List nodes, int level, int currentLevel) {
if (currentLevel >= level) {
return;
}
for (T child : nodes) {
if (child.getParentId() != null && child.getParentId().equals(node.getId())) {
if (node.getChildren() == null) {
node.setChildren(new ArrayList());
}
node.getChildren().add(child);
buildChildren(child, nodes, level, currentLevel + 1);
}
}
}
}
public class MyTreeVo implements TreeNode {
/**
* 主键
*/
private String id;
/**
* 父节点ID
*/
private String pId;
/**
* 子级
*/
private List children = Lists.newArrayList();
//其他属性……
public List getChildren() {
return children;
}
public String getId() {
return id;
}
public String getpId() {
return pId;
}
//其他属性的getter、setter……
-- pId可以传入null,也可以传入需要从哪个节点(X)开始构造的 X的id
-- pId比如可以传入3、样例中的 “二、噢噢噢噢”的id=“e6ee51485389495cb923a122be800012”。然后构建出来的,就是“二、噢噢噢噢”的下级树
List tree = TreeUtilQz.buildTree(vos,null);
//tree就是构建好的树结构数据
{
"data": [
{
"id": "e6ee51485389495cb923a122be800011",
"pId": "",
"name": "一、钢管钢管",
"children": [
{
"id": "e6ee51485389495cb923a122be800014",
"pId": "e6ee51485389495cb923a122be800011",
"name": "(二)嘎嘎嘎嘎嘎",
"children": []
},
{
"id": "e6ee51485389495cb923a122be800013",
"pId": "e6ee51485389495cb923a122be800011",
"name": "(一)顶顶顶顶",
"children": []
}
]
},
{
"id": "e6ee51485389495cb923a122be800012",
"pId": "",
"name": "二、噢噢噢噢",
"children": [
{
"id": "e6ee51485389495cb923a122be800015",
"pId": "e6ee51485389495cb923a122be800012",
"name": "二的下级",
"children": [
{
"id": "e6ee51485389495cb923a122be800016",
"pId": "e6ee51485389495cb923a122be800015",
"name": "二的下级的下级",
"children": []
}
]
}
]
}
]
}
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