Question

我将Object（我无法控制）映射到jsonString，映射后我在JSON中获得重复的键值对，示例

 {
 "id":"123",
 "email":"someEmail@gmail.com",
 "UserName":"someOne",
 "EMAIL":"someEmail@gmail.com"
 }

副本完全相同，只是它是大写字母。我试图获得jsonInString格式而不重复。像这样：

 {
 "id":"123",
 "email":"someEmail@gmail.com",
 "UserName":"someOne"
 }

我试过了

String jsonInStringWithOutDuplication=mapper.enable(
    JsonParser.Feature.STRICT_DUPLICATE_DETECTION).writeValueAsString(users);

没有运气，有什么建议吗？

Answer 1

如果您找不到配置ObjectMapper来过滤掉重复属性的方法，可以将有问题的对象序列化为JSON，然后将JSON序列化为Map对象，合并重复属性并再次将其序列化为JSON：

Map<String, String> objectWithDuplicates = new HashMap<>();
map.put("name", "MyName");
map.put("email", "em@ail");
map.put("EMAIL", "em@ail");

ObjectMapper mapper = new ObjectMapper();

String jsonWithDuplicates = mapper.writeValueAsString(objectWithDuplicates);
Map<String, Object> attributesWithDuplicates = mapper
        .readValue(jsonWithDuplicates, Map.class);

Map<String, Object> withoutDuplicates = new HashMap<>();
attributesWithDuplicates.forEach((key, value) -> {
    if (! withoutDuplicates.containsKey(key.toLowerCase())) {
        withoutDuplicates.put(key.toLowerCase(), value);
    }
});
String json = mapper.writeValueAsString(withoutDuplicates);

Answer 2

杰克逊的ObjectMapper有一个功能，可以将相同的键放入数组中。这不是可以帮助你的东西吗？

ObjectMapper objectMapper = new ObjectMapper();
objectMapper.registerModule(new GuavaModule());
objectMapper.configure(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY, true);    
Multimap resultAsMultimap = mapper.readValue(json, Multimap.class);
System.out.println(resultAsMultimap);

从java中的json中删除重复的键和值

2 个答案: