Create a tree structure

 //Create a tree structurepublic List buildTree() {List treeMenus = new ArrayList<>();for (BasicMenuInfoVo menuNode : getRootNode()) {menuNode = buildChildTree(menuNode);treeMenus.add(menuNode);}return treeMenus;}//get root nodeprivate List getRootNode() {List rootMenuLists = new ArrayList<>();for (BasicMenuInfoVo menuNode : menuList) {if (menuNode.getParentId().longValue() == 0) {menuNode.setAccess(permissionMap.get(menuNode.getPermissionId()));if (flag == 0) rootMenuLists.add(menuNode);if (flag == 1 && menuNode.getState() == 1) rootMenuLists.add(menuNode);}}return rootMenuLists;}// recursively, create a subtree structureprivate BasicMenuInfoVo buildChildTree(BasicMenuInfoVo pNode) {List childMenus = new ArrayList<>();for (BasicMenuInfoVo menuNode : menuList) {if (menuNode.getParentId().longValue() == pNode.getId().longValue()) {menuNode.setAccess(permissionMap.get(menuNode.getPermissionId()));if (flag == 0) childMenus.add(buildChildTree(menuNode));if (flag == 1 && menuNode.getState() == 1) childMenus.add(buildChildTree(menuNode));}}pNode.setRoutes(childMenus);return pNode;}