專案中查詢選單目錄表，裡面有父子關係，根據父子關係，把選單目錄表展示成樹的形式

　　查詢出所有的選單目錄內容

SysUserMVO sessionUser = SecurityManager.getSessionUser();
List<MenuCatalogMVO> catalogs = sessionUser.getMenuCatalog();

　　將資料根據父子關係展示成json格式

Map<String,Object> leafMap = getLevelMenuCatalog(catalogs,leafNodeIds,MENU_LV);

public Map<String, Object> getLevelMenuCatalog(List<MenuCatalogMVO> catalogs, List<String> parentCatalogIds, String... catalogCodes) {
    List
 
<Object> treeList = new LinkedList<Object>();
    List<String> leafNodeId = new LinkedList<String>();
    Map<String, Object> rsMap = new HashMap<String, Object>();
    for (MenuCatalogMVO menuCatalog : catalogs) {
        if ((parentCatalogIds != null && parentCatalogIds.size() > 0) ? parentCatalogIds.contains(menuCatalog.getParentCatalogId()) : StringUtils.isBlank(menuCatalog.getParentCatalogId())) {
            
 
if (catalogCodes.length > 0 && Arrays.asList(catalogCodes).contains(menuCatalog.getCatalogCode())) {
                Map<String, Object> treeMap = new HashMap<String, Object>();
                treeMap.put("id", menuCatalog.getMenuCatalogId());
                treeMap.put("text", menuCatalog.getCatalogName());
                treeMap.put(
 
"code", menuCatalog.getCatalogCode());
                treeMap.put("parentId", menuCatalog.getParentCatalogId());
                childMenuCatalog(treeMap, catalogs, catalogCodes, leafNodeId);
                treeList.add(treeMap);
            }
        }
    }
    rsMap.put("LEAFNODEIDS", leafNodeId);
    JSONArray jo = JSONArray.fromObject(treeList);
    String rs = jo.toString();
    rsMap.put("RS", rs);
    return rsMap;
}

public void childMenuCatalog(Map<String, Object> parentMap, List<MenuCatalogMVO> catalogs, String[] catalogCodes, List<String> leafNodeId) {
    List<Object> treeList = new LinkedList<Object>();
    for (MenuCatalogMVO menuCatalog : catalogs) {
        Map<String, Object> treeMap = new HashMap<String, Object>();
        if (catalogCodes.length > 0 && Arrays.asList(catalogCodes).contains(menuCatalog.getCatalogCode())) {
            if (parentMap.get("id").equals(menuCatalog.getParentCatalogId())) {
                treeMap.put("id", menuCatalog.getMenuCatalogId());
                treeMap.put("text", menuCatalog.getCatalogName());
                treeMap.put("code", menuCatalog.getCatalogCode());
                treeMap.put("parentId", menuCatalog.getParentCatalogId());
                childMenuCatalog(treeMap, catalogs, catalogCodes, leafNodeId);
                treeList.add(treeMap);
            }
        }
    }
    if (treeList.size() > 0) {
        parentMap.put("children", treeList);
    } else {
        leafNodeId.add((String) parentMap.get("id"));
    }
}

　catalog = (String) leafMap.get("RS");

　　這樣打印出的catalog就是有層級關係的了