Question

我的输入中有一个总共13个HashMap的列表。每个HashMap只有两个键“ fieldName”和“ accessibilityType”以及相应的值：

"fieldAccessibility": [
    {
        "fieldName": "firstName",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "lastName",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "avatarUrl",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "username",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "birthDate",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "phoneNumbers",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "email",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "language",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "externalId",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "externalCode",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "punchBadgeId",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "minor",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "seniorityDate",
        "accessibilityType": "EDITABLE"
    }
]

我正在尝试遍历此过程，并将“ accessibilityType”的值更改为“ READ”，其中“ fieldName”是“ birthDate”。有人可以说一下这样做的有效方法。到目前为止，这是我尝试读取和打印每个键值对的尝试：

final List<HashMap<String, String>> list = some code to get the input;
    for (HashMap<String, String> m : list)
    {
        for (HashMap.Entry<String, String> e : m.entrySet())
        {
            String key = e.getKey();
            String value = e.getValue();

            System.out.println("SEE HERE TEST " + key + " = " + value);

        }}

Answer 1

从JDK-8开始，可以使用forEach按照以下步骤进行操作：

list.forEach(map -> {
      String fieldName = map.get("fieldName");
      if("birthDate".equals(fieldName)) map.put("accessibilityType", "READ");
});

Answer 2

您可以这样做

List<Map<String, String>> updatedMaps = list.stream()
        .map(m -> m.entrySet().stream().collect(Collectors.toMap(
        Map.Entry::getKey,
        e -> m.containsValue("birthDate") && e.getKey().equals("accessibilityType") ? "READ" : e.getValue())))
        .collect(Collectors.toList());

浏览每张地图，同时将其映射到新地图。键保持不变，只有值可以更改。如果您的地图包含键birthDate，并且当前条目的键是accessibilityType，则将READ作为该地图条目的新值。否则，请保留现有值。最后，将所有新地图收集到结果容器中。

如何更改与具有相同键的HashMap列表中的键关联的值？

2 个答案: