Bootstrap实践之Java递归转换treeview结构数据

前文中我表示treeview使用的数据格式，需要多层级节点嵌套的结构，而非所有菜单均为一级的数据格式，在使用的时候，我们不得不需要将一个一层结构的数据再转换成多层级的实现，参考如下数据所示：

① 初始数据结构

[
  {
    "id": 1,
    "name": "北京市",
    "parentId": -1
  },
  {
    "id": 2,
    "name": "海淀区",
    "parentId": 1
  },
  {
    "id": 3,
    "name": "朝阳区",
    "parentId": 1
  },
  {
    "id": 4,
    "name": "湖北省",
    "parentId": -1
  },
  {
    "id": 5,
    "name": "武汉市",
    "parentId": 4
  },
  {
    "id": 6,
    "name": "襄阳市",
    "parentId": 4
  },
  {
    "id": 7,
    "name": "襄城区",
    "parentId": 6
  },
  {
    "id": 8,
    "name": "襄州区",
    "parentId": 6
  },
  {
    "id": 9,
    "name": "樊城区",
    "parentId": 6
  },
  {
    "id": 10,
    "name": "老河口市",
    "parentId": 6
  },
  {
    "id": 11,
    "name": "谷城县",
    "parentId": 6
  },
  {
    "id": 12,
    "name": "南漳县",
    "parentId": 6
  },
  {
    "id": 13,
    "name": "枣阳市",
    "parentId": 6
  },
  {
    "id": 14,
    "name": "保康县",
    "parentId": 6
  },
  {
    "id": 15,
    "name": "宜城市",
    "parentId": 6
  }
]

② treeview需要的数据结构

[
   {
     "nodeId": 1,
     "nodes": [
       {
         "nodeId": 2,
         "text": "海淀区"
       },
       {
         "nodeId": 3,
         "text": "朝阳区"
       }
     ],
     "text": "北京市"
   },
   {
     "nodeId": 4,
     "nodes": [
       {
         "nodeId": 5,
         "text": "武汉市"
       },
       {
         "nodeId": 6,
         "nodes": [
           {
             "nodeId": 7,
             "text": "襄城区"
           },
           {
             "nodeId": 8,
             "text": "襄州区"
           },
           {
             "nodeId": 9,
             "text": "樊城区"
           },
           {
             "nodeId": 10,
             "text": "老河口市"
           },
           {
             "nodeId": 11,
             "text": "谷城县"
           },
           {
             "nodeId": 12,
             "text": "南漳县"
           },
           {
             "nodeId": 13,
             "text": "枣阳市"
           },
           {
             "nodeId": 14,
             "text": "保康县"
           },
           {
             "nodeId": 15,
             "text": "宜城市"
           }
         ],
         "text": "襄阳市"
       }
     ],
     "text": "湖北省"
   }
 ]

参考代码

package cn.chendd.tips.examples.treeview;
 
import ...;
 
 /**
  * 数据转换测试
  *
  * @author chendd
  * @date 2020/x/xx 22:34
  */
 public class DataConvertTest {
 
     private Integer ROOT_ID = -1;//约定根节点为-1
     private List<City> cityList;
 
     @Test
     public void test(){
         System.out.println("======原始数据======");
         System.out.println(JSONObject.toJSONString(cityList , true));
         Stream<City> rootCity = cityList.stream().filter(city -> ROOT_ID.equals(city.getParentId()));
         List<Treeview> treeviewList = new ArrayList<>();
         this.convertTreeview(rootCity, treeviewList);
         for (Treeview treeview : treeviewList) {
             this.collectList(treeview , this.cityList);
         }
         System.out.println("======转换后的数据======");
         System.out.println(JSON.toJSONString(treeviewList , true));
     }
 
     /**
      * 获取原始数据中的一级菜单
      */
     private void convertTreeview(Stream<City> cityStream, List<Treeview> treeviewList) {
         cityStream.forEach(city -> {
             Treeview treeview = new Treeview();
             treeview.setNodeId(city.getId());
             treeview.setText(city.getName());
             treeview.setState(null);
             treeview.setNodes(null);
             treeviewList.add(treeview);
         });
     }
 
     /**
      * 遍历一级菜单，并递归调用字级菜单，查找对应的菜单节点
      */
     private void collectList(Treeview treeview, List<City> cityList) {
         Integer nodeId = treeview.getNodeId();
         for (City city : cityList) {
             Integer parentId = city.getParentId();
             if(parentId != null && parentId.equals(nodeId)){
                 if(treeview.getNodes() == null){
                     treeview.setNodes(new ArrayList<>());
                 }
                 Treeview childMenuTreeview = new Treeview();
                 childMenuTreeview.setNodeId(city.getId());
                 childMenuTreeview.setText(city.getName());
                 childMenuTreeview.setState(null);
                 treeview.getNodes().add(childMenuTreeview);
                 this.collectList(childMenuTreeview , cityList);
             }
         }
     }
 
     @Before
     public void init(){
         cityList = new ArrayList<>();
         cityList.add(new City(1 , "北京市" , ROOT_ID));
         cityList.add(new City(2 , "海淀区" , 1));
         cityList.add(new City(3 , "朝阳区" , 1));
         cityList.add(new City(4 , "湖北省" , ROOT_ID));
         cityList.add(new City(5 , "武汉市" , 4));
         cityList.add(new City(6 , "襄阳市" , 4));
         cityList.add(new City(7 , "襄城区" , 6));
         cityList.add(new City(8 , "襄州区" , 6));
         cityList.add(new City(9 , "樊城区" , 6));
         cityList.add(new City(10 , "老河口市" , 6));
         cityList.add(new City(11 , "谷城县" , 6));
         cityList.add(new City(12 , "南漳县" , 6));
         cityList.add(new City(13 , "枣阳市" , 6));
         cityList.add(new City(14 , "保康县" , 6));
         cityList.add(new City(15 , "宜城市" , 6));
     }
 
 }

源码下载

https://gitee.com/88911006/chendd-examples/tree/master/tips/test/main/java/cn/chendd/tips/examples/treeview