查询数据库生成树状数据逻辑，全部查询，并且生成树状结构，全部查出，并且在内存中生成树形结构，再转为map存储，key为父节点ID，value为数据集合，进行封装-Query tree data generated logic, all queries, and generate a tree structure, identified all, and generate a tree structure in memory, then stored as map, key parent nod