查詢菜單樹

public List<Map<String, Object>> queryCategoryInfo() {List<Map<String, Object>> allMenu = queryAllCategory();//根節(jié)點(diǎn)List<Map<String, Object>> rootMenu = new ArrayList<Map<String, Object>>();for (Map<String, Object> nav : allMenu) {String parentId = String.valueOf(nav.get("parent_id"));if(parentId.equals("0")){//父節(jié)點(diǎn)是0的，為根節(jié)點(diǎn)。rootMenu.add(nav);}}/* 根據(jù)Menu類的order排序 */ // Collections.sort(rootMenu, order());//為根菜單設(shè)置子菜單，getClild是遞歸調(diào)用的for (Map<String, Object> nav : rootMenu) {/* 獲取根節(jié)點(diǎn)下的所有子節(jié)點(diǎn) 使用getChild方法*/String id = String.valueOf(nav.get("category_id"));List<Map<String, Object>> childList = getChild(id, allMenu); // nav.setChildren(childList);//給根節(jié)點(diǎn)設(shè)置子節(jié)點(diǎn)nav.put("child", childList);}return rootMenu;} /*** 獲取子節(jié)點(diǎn)* @param id 父節(jié)點(diǎn)id* @param allMenu 所有菜單列表* @return 每個根節(jié)點(diǎn)下，所有子菜單列表*/private List<Map<String, Object>> getChild(String id,List<Map<String, Object>> allMenu){//子菜單List<Map<String, Object>> childList = new ArrayList<Map<String, Object>>();for (Map<String, Object> nav : allMenu) {// 遍歷所有節(jié)點(diǎn)，將所有菜單的父id與傳過來的根節(jié)點(diǎn)的id比較//相等說明：為該根節(jié)點(diǎn)的子節(jié)點(diǎn)。String parentId = String.valueOf(nav.get("parent_id"));if(id.equals(parentId)){childList.add(nav);}}//遞歸for (Map<String, Object> nav : childList) {String tempId = String.valueOf(nav.get("category_id"));//nav.setChildren(,getChild(tempId, allMenu));nav.put("child", getChild(tempId, allMenu));}//Collections.sort(childList,order());//排序//如果節(jié)點(diǎn)下沒有子節(jié)點(diǎn)，返回一個空List（遞歸退出）if(childList.size() == 0){return new ArrayList<Map<String, Object>>();}return childList;}

總結(jié)

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