使用效果

初始化加载顶层节点，点击各层的>加载该节点的子节点，加载后>标识去除不再重复加载。

前端代码

vue ant-design组件

• tree-data，树节点，children方式或id、pid方式
• load-data，展开节点事件，响应该事件加载子节点

<a-tree-select v-model:value="sample" :tree-data="sampleTreeData" :load-data="onLoadSampleTreeData"
        style="width: 100%" allowClear treeDataSimpleMode 
        :dropdown-style="{ maxHeight: '400px', overflow: 'auto' }"
        placeholder="请选择测试计划/样品" >                           
</a-tree-select>

定义interface

• 异步加载通过id和pid匹配，因此没有children属性，替换为id何pid
• 添加level便于后端识别，如果后端为一个表内的数据且通过id和pid或parentid关联则不需要

export interface TreeDataItem {
  id: string | number;
  pId: string | number;
  value: string;
  title: string;
  isLeaf?: boolean;
  level: string;
}

加载（跟节点）数据

调用后端查询数据并赋值给treeData，treeData绑定控件的treeData属性。

async function loadSampleTreeRootData() {
  // loading.value = true
  let params = {"level":"0"};
  sampleTreeNode(params).then(result => { 
      console.log(result)
      sampleTreeData.value = sampleTreeData.value.concat(result);
      }).finally(() => { 
  // loading.value = false  
loadSampleTreeRootData()

加载（节点的子节点）数据

响应控件的load-data事件，查询要展开节点的子节点数据，并合并到treeData中，控件会根据id和pid显示层级关系。

const onLoadSampleTreeData = (treeNode: any) => { 
      return new Promise((resolve: (value?: unknown) => void) => {
        // console.log("node:");
        // console.log(treeNode.dataRef)
        const { id,level,value } = treeNode.dataRef; 
        // console.log("id:"+id);
        // console.log("level:"+level);
        // console.log("value:"+value); 
        setTimeout(() => { 
            let nextLevel = "1";
            if(level=="1")nextLevel="2";
            let params = {"level":nextLevel, "id":id}; 
            sampleTreeNode(params).then(result => { 
            //    console.log("result:");
            //    console.log(result); 
                sampleTreeData.value = sampleTreeData.value.concat(result); 
            }).finally(() => { 
          resolve();
        }, 300);
    };

后端代码

定义treeNodeVO

pId和isLeaf注解下，避免springMVC默认的序列化。 （默认序列化为pid\leaf）

@Data
public class PlantSampleTreeNodeVO {
    //key
    private String id;
//    private long id;
    @JsonProperty("pId")
    private String pId;
//    private long pId;
    //树节点显示的内容
    private String title;
    //默认根据此属性值进行筛选（其值在整个树范围内唯一）
    private Object value;
    //是否是叶子节点
    @JsonProperty("isLeaf")
    private boolean isLeaf;
    //节点层级
    private String level;
}

controller提供数据

因为是异步加载，三个表的查询可在一个service中实现，或直接使用各自的treeNode的service。

@Override
	public List<PlantSampleTreeNodeVO> getPlantSampleTreeNodeVO(String level, String id) {
		List<PlantSampleTreeNodeVO> plantSampleTreeVONodeList = new ArrayList<>();
		switch (level) {//顶级节点
			case "0":
				//查询所在班组,plant member
				List<Plant> plantList = plantService.list();
				for (Plant plant : plantList) {
					//创建顶层树/节点
					PlantSampleTreeNodeVO plantNode = new PlantSampleTreeNodeVO();
//					System.out.println(plant.getId());
//					System.out.println(Long.parseLong(plant.getId()));
//					System.out.println(Long.valueOf(plant.getId()).longValue());
//					plantNode.setId(Long.parseLong(plant.getId()));
					plantNode.setId(plant.getId());
					plantNode.setPId("0");//and-design tree指定的值
					plantNode.setValue(plant.getId());
					plantNode.setTitle(plant.getPlantName());
					plantNode.setLeaf(false);//需根据业务逻辑判断是否有子节点，省略处理
					plantNode.setLevel("0");
					plantSampleTreeVONodeList.add(plantNode);
				break;
			case "1":
				//查询班组相关的样品组模板
				QueryWrapper<SampleGroupTemplate> sampleGroupTemplateQueryWrapper = new QueryWrapper<>();
				sampleGroupTemplateQueryWrapper.eq("plantid",id);
				List<SampleGroupTemplate> sampleGroupTemplateList = sampleGroupTemplateService.list(sampleGroupTemplateQueryWrapper);
				//循环各样品组模板显示其下的测试计划/样品
				for(SampleGroupTemplate sampleGroupTemplate: sampleGroupTemplateList){
					//添加到树上
					PlantSampleTreeNodeVO sampleGroupNode = new PlantSampleTreeNodeVO();
//					sampleGroupNode.setId(Long.parseLong(sampleGroupTemplate.getId()));
					sampleGroupNode.setId(sampleGroupTemplate.getId());
//					sampleGroupNode.setPId(Long.parseLong(id));
					sampleGroupNode.setPId(id);
					sampleGroupNode.setValue(sampleGroupTemplate.getId());
					sampleGroupNode.setTitle(sampleGroupTemplate.getSampleGroupName());
					sampleGroupNode.setLeaf(false);
					sampleGroupNode.setLevel("1");
					plantSampleTreeVONodeList.add(sampleGroupNode);
				break;
			case "2":
				//查询样品组模板显示其下的测试计划/样品
				QueryWrapper<SgtSample> sampleQueryWrapper = new QueryWrapper<>();
				sampleQueryWrapper.eq("templateid",id);
				List<SgtSample> sampleList = this.list(sampleQueryWrapper);
				//循环各样品
				for(SgtSample sample: sampleList) {
					PlantSampleTreeNodeVO sampleNode = new PlantSampleTreeNodeVO();
//					sampleNode.setId(Long.parseLong(sample.getId()));
					sampleNode.setId(sample.getId());
//					sampleNode.setPId(Long.parseLong(id));
					sampleNode.setPId(id);
					sampleNode.setValue(sample.getId());
					sampleNode.setTitle(sample.getSampleName());
					sampleNode.setLeaf(true);//叶子节点
					sampleNode.setLevel("2");
					plantSampleTreeVONodeList.add(sampleNode);
				break;
		return plantSampleTreeVONodeList;
	}