java ssm使用递归写树形结构

实体类:

private String dspId;

    private String parentId; //父类id

    private String dataName;

    private Integer sortingNumber;

    private String remarks;

    private Date createTime;

    private Date updateTime;

    private Date deleteTime;

    private Integer dataFlag;

    private Integer anId;

    private Integer isParent;//是否有父类

    private List<DataSpecies> chlidSpecies;

dao层和接口使用mybatis逆向生成,这里就不住解释.

service层:

    public List<DataSpecies> findDataspecies() {
       // TODO Auto-generated method stub
   //查询所有的结果
       DataSpeciesExample example = new DataSpeciesExample();
       Criteria criteria = example.createCriteria();
       criteria.andDataFlagEqualTo(0);
       List<DataSpecies> dataSpecies = dataspeciesMapper.selectByExample(example);
       //创建最后的结果想最后结果填充数据
       List<DataSpecies> dataSpeciesList= new ArrayList<>();
   for (DataSpecies species : dataSpecies) {
           if(StringUtils.isBlank(species.getParentId()) ){
               //一级菜单没有ParentId
               dataSpeciesList.add(species);
           }
   }
   //为一级菜单设计子菜单使用getchild递归
   for (DataSpecies daSpecies : dataSpeciesList) {
       daSpecies.setChlidSpecies(getChild(daSpecies.getDspId(),dataSpecies));//这里getchild方法是递归
   }
       return dataSpeciesList;
   }

//递归方法:

    public List<DataSpecies> getChild(String id,List<DataSpecies> rootDataSpecies){
       //创建子菜单
       List<DataSpecies> speciesList = new ArrayList<>();
       for (DataSpecies dataSpecies : rootDataSpecies) {
           //遍历蓑鲉节点 ,将父类id与传过来的id进行对比
           if(StringUtils.isNotBlank(dataSpecies.getParentId())){
               if(dataSpecies.getParentId().equals(id)){
                   speciesList.add(dataSpecies);
               }
           }
       }
       //把子菜单循环遍历
       for (DataSpecies childSpecies : speciesList) {
           if(childSpecies.getIsParent()==1){
               childSpecies.setChlidSpecies(getChild(childSpecies.getDspId(),rootDataSpecies));
           }
       }
       if(speciesList.size()==0){
           return null;
       }
       return speciesList;
   }

web层直接调用service 的方法就行,这里不做说明.

来源：https://www.cnblogs.com/guotao123/p/8818108.html

标签

递归调用

树形结构

递归

ssm