Java boon JSON解析器从输出中删除空值

Question

我有一个小函数，它接受输入的JSON字符串，使用boon将其解析为Map，替换特定键的值，返回修改后的Map的JSON字符串。

代码如下：

// inputJson = {"key3":"A","key2":"B","key1":null,"keyX":[{"x":2019,"y":123,"z":456},{"x":2017,"y":234,"z":345},{"x":2018,"y":456,"z":567}]}

private static String sorter(String inputJson) {
    JsonParserAndMapper mapper = new JsonParserFactory().strict().create();

    Map<String, Object> map = mapper.parseMap(inputJson);

    List<?> l1 = (List<?>) map.get("keyX");

    sort(l1, Sort.sortBy("x"));

    map.replace("keyX", l1);

    for (String x: map.keySet())
        System.out.println(map.get(x));

    String outputJson = toJson(map);  // problem seems to be here

    return outputJson

// outputJson = {"key2":"B","key3":"A","keyX":[{"x":2017,"y":234,"z":345},{"x":2018,"y":456,"z":567},{"x":2019,"y":123,"z":456}]}

问题是，当我执行toJson(map)时，它会删除带有null值的键。因此，如果inputJson包含一个空值的键，那么它不会出现在输出中。(注意:输出中缺少key1 )

如何才能在不丢失空字段的情况下对其进行解析？

Answer 1

使用toJson时，您使用的是默认的序列化程序工厂。来自boon源代码：

public class JsonFactory {


    private static ObjectMapper json = JsonFactory.create();

    public static ObjectMapper create () {
        JsonParserFactory jsonParserFactory = new JsonParserFactory();
        jsonParserFactory.lax();

        return new ObjectMapperImpl(jsonParserFactory,  new JsonSerializerFactory());
    }
....
)

尝试使用带有includeNulls()的序列化器工厂，而不是使用toJson

JsonSerializer factory = new JsonSerializerFactory().includeNulls().create();