分组方法

public static Map<String, List<Map<String, Object>>> list2Map(String key, List<Map<String, Object>> data) {

 

if (data == null) return null;

Map<String, List<Map<String, Object>>> result = new HashMap<String, List<Map<String, Object>>>();

for (Map<String, Object> map : data) {

if (map.get(key) == null) continue;

List<Map<String, Object>> tempList = result.get(map.get(key).toString());

// 如果取不到数据,那么直接new一个空的ArrayList

if (tempList == null) {

tempList = new ArrayList<>();

tempList.add(map);

result.put(map.get(key).toString(), tempList);

} else {

// 某个sku之前已经存放过了,则直接追加数据到原来的List里

tempList.add(map);

}

}

return result;

}