java - 从 map 数组列表中获取唯一名称和相应的金额总和

Question

我正在尝试迭代数组列表。 List<Map<String, Object>> majorList=new ArrayList<Map<String, Object>>();

数据格式为

1. {"ledger": "A","basicAmt": 10,"消费税": 2},{"ledger": "B","exciseAmt": 20,"grossAmt": 3}, {"ledger": "A","basicAmt": 30,"消费税": 5},{"ledger": "C","exciseAmt": 50,"grossAmt": 10},{“ledger”:“B”，“basicAmt”:40，“消费税”:8}，

   所需的结果如下:

2. {"ledger": "A","basicAmt": 40,"消费税": 7},{"ledger": "B","exciseAmt": 60,"grossAmt": 11},{"ledger": "C","basicAmt": 50,"消费税": 10},

Answer 1

您必须填充一个新的映射，然后根据公共(public)键添加值。总结后最好有一个 Map<String, Object>因为所有 map 都将用于唯一的分类帐。

    Map<String, Map<String, Object>> sumMap = new HashMap<String, Map<String,Object>>();
    for (Map<String, Object> abc : majorList) {
        Map temp = sumMap.get((String) abc.get("ledger"));
        if (temp == null) {
            sumMap.put((String) abc.get("ledger"), abc);
        } else {
            for (Entry<String, Object> entry : abc.entrySet()) {
                if (!entry.getKey().equals("ledger")) {
                    temp.put(entry.getKey(),
                            (Integer) temp.get(entry.getKey())
                                    + (Integer) entry.getValue());
                }
            }
        }
    }