查询树形目录（内存遍历成树返回）

实体

@Data
@TableName("dtp_sm_servicetype")
@ApiModel(value = "SmServicetype对象", description = "服务类型")
@EqualsAndHashCode(callSuper = true)
public class SmServicetype extends BaseEntity {@ApiModelProperty("服务类型名称")private String name;@ApiModelProperty("服务标题")private String title;@ApiModelProperty("服务分类描述")private String descinfo;@ApiModelProperty("服务分类父节点编号")private Long parentId;@ApiModelProperty("排序")private Integer orderIndex;// 存储下（子）级节点信息@TableField(exist = false)private List<SmServicetype> childrenList;
}

调用

/*** 服务类型 分页*/
@ApiOperation(value = "查询所有服务类型", notes = "传入smServicetype")
public R<List<SmServicetypeVO>> serviceTypeTree(SmServicetype smServicetype) {//查询所有树数据listList<SmServicetype> allList = smServicetypeService.list();// 内存中递归成树List<SmServicetype> typeTreeList = this.selectSmServicetypeTrees(allList);return R.data(SmServicetypeWrapper.build().listVO(typeTreeList));
}private List<SmServicetype> selectSmServicetypeTrees(List<SmServicetype> smServicetypeList) {List<SmServicetype> collect = smServicetypeList.stream().filter(item -> item.getParentId() == -1)   //ParentId=-1的节点为根节点（根据具体情况修改）    filter为过滤不符合条件的.map(item -> {item.setChildrenList(getChildrenList(item, smServicetypeList));return item;}).collect(Collectors.toList());return collect.size() == 0 ? smServicetypeList : collect;}private List<SmServicetype> getChildrenList(SmServicetype smServicetype, List<SmServicetype> smServicetypeList) {List<SmServicetype> collect = smServicetypeList.stream().filter(item -> item.getParentId().equals(smServicetype.getId())).map(item -> {item.setChildrenList(getChildrenList(item, smServicetypeList));return item;}).collect(Collectors.toList());return collect;
}