I won’t say much nonsense, just post the code to you, the specific code is as follows:
// Menu tree structure public JSONArray treeMenuList(JSONArray menuList, int parentId) { JSONArray childMenu = new JSONArray(); for (Object object: menuList) { JSONObject jsonMenu = JSONObject.fromObject(object); int menuId = jsonMenu.getInt("id"); int pid = jsonMenu.getInt("parentId"); if (parentId == pid) { JSONArray c_node = treeMenuList(menuList, menuId); jsonMenu.put("childNode", c_node); childMenu.add(jsonMenu); } } return childMenu; } public static void main(String args[]) { MenuCacheService menuCacheService = new MenuCacheService(); JSONArray jsonArray = new JSONArray(); Menu menu1 = new Menu(); menu1.setId(1l); menu1.setParentId(0); menu1.setLevel(0); Menu menu2 = new Menu(); menu2.setId(2l); menu2.setParentId(0); menu2.setLevel(0); Menu menu3 = new Menu(); menu3.setId(3l); menu3.setParentId(2); menu3.setLevel(1); Menu menu4 = new Menu(); menu4.setId(4l); menu4.setParentId(2); menu4.setLevel(1); Menu menu5 = new Menu(); menu5.setId(5l); menu5.setParentId(4); menu5.setLevel(2); Menu menu6 = new Menu(); menu6.setId(6l); menu6.setParentId(1); menu6.setLevel(1); jsonArray.add(menu1); jsonArray.add(menu2); jsonArray.add(menu3); jsonArray.add(menu4); jsonArray.add(menu5); jsonArray.add(menu6); System.out.print(menuCacheService.treeMenuList(jsonArray,0)); }ps:java implements recursive traversal of the tree (used to implement the collapse menu)
1. Core algorithm
package com.zf.tag.dao;import java.util.ArrayList;import java.util.List;import com.zf.tag.entity.dept.Dept;public class DeptDao extends BaseDao{public static List<Dept> searchAllDept() throws Exception{List<Object[]> listAllObject=new ArrayList<Object[]>();List<Object[]> tmp=new ArrayList<Object[]>();List<Dept> listAllDept=new ArrayList<Dept>();String sql="select id,dname,up_did from tbl_dept";listAllObject=getResult(sql);for (Object[] row : listAllObject) {Object[] ro = new Object[3];ro[0] = row[0];ro[1] = row[1];ro[2] = row[2];tmp.add(row);}for (Object[] row : tmp) {if (null == row[2]) {Dept d = new Dept();d.setId(Integer.parseInt(String.valueOf(row[0])));d.setDname(String.valueOf(row[1]));listAllDept.add(d);fomateDept(tmp, d);}}return listAllDept;}private static void fomateDept(List<Object[]> tmp, Dept dept) {for (Object[] row : tmp) {if ((null != row[2])&& Integer.parseInt(String.valueOf(row[2])) == dept.getId()) {Dept d = new Dept();d.setId(Integer.parseInt(String.valueOf(row[0])));d.setDname(String.valueOf(row[1]));List<Dept> list = dept.getChildren();if (list == null) {list = new ArrayList<Dept>();}list.add(d);dept.setChildren(list);fomateDept(tmp, d);}}}}}2. Entity category (department)
package com.zf.tag.entity.dept;import java.util.List;public class Dept {private Integer id;private String dname;private List<Dept> children;public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getDname() {return dname;}public void setDname(String dname) {this.dname = dname;}public List<Dept> getChildren() {return children;}public void setChildren(List<Dept> children) {this.children = children;}public String toString(){return this.getDname();}}The above is the relevant content of Java recursive traversal tree structure introduced to you by the editor. I hope it will be helpful to everyone!