JSONObject 删除空值对 [英] JSONObject remove empty value pairs

问题描述

这是我的 Json 文件:

Here is my Json File:

{  
   "models":{},
   "path":[  
      {  
         "path":"/web-profiles",
         "operations":[  
            {  
               "type":"",
               "responseMessages":[]
            }
         ]
      }
   ],
   "produces":[]
}

如果键的值为空(包括 []、""、{}).如何从 Json 文件中删除这些对.

If the values of keys are empty (includes [], "", {}). How can I remove those pairs from Json file.

1. 我尝试使用 JSONObject 内置函数来删除不必要的对.但是，它不起作用.
2. 我尝试使用字符串方法逐行处理.它有太多案例，我无法在我的代码中涵盖所有这些案例.(例如，子键 'operations'，当你想删除所有空值时，这个 key(operations) 值对也应该被删除.)有什么想法吗?

推荐答案

如果你使用javax.api API:

If you use javax.api API:

public static JsonArray removeNull(JsonArray array) {
    JsonArrayBuilder builder = Json.createArrayBuilder();
    int i = 0;
    for (Iterator<JsonValue> it = array.iterator(); it.hasNext(); ++i) {
        JsonValue value = it.next();
        switch (value.getValueType()) {
        case ARRAY:
            JsonArray a = removeNull(array.getJsonArray(i));
            if (!a.isEmpty())
                builder.add(a);
            break;
        case OBJECT:
            JsonObject object = removeNull(array.getJsonObject(i));
            if (!object.isEmpty())
                builder.add(object);
            break;
        case STRING:
            String s = array.getString(i);
            if (s != null && !s.isEmpty())
                builder.add(s);
            break;
        case NUMBER:
            builder.add(array.getJsonNumber(i));
            break;
        case TRUE:
        case FALSE:
            builder.add(array.getBoolean(i));
            break;
        case NULL:
            break;
        }
    }
    return builder.build();
}

public static JsonObject removeNull(JsonObject obj) {
    JsonObjectBuilder builder = Json.createObjectBuilder();
    for (Iterator<Entry<String, JsonValue>> it = obj.entrySet().iterator(); it.hasNext();) {
        Entry<String, JsonValue> e = it.next();
        String key = e.getKey();
        JsonValue value = e.getValue();
        switch (value.getValueType()) {
        case ARRAY:
            JsonArray array = removeNull(obj.getJsonArray(key));
            if (!array.isEmpty())
                builder.add(key, array);
            break;
        case OBJECT:
            JsonObject object = removeNull(obj.getJsonObject(key));
            if (!object.isEmpty())
                builder.add(key, object);
            break;
        case STRING:
            String s = obj.getString(key);
            if (s != null && !s.isEmpty())
                builder.add(key, s);
            break;
        case NUMBER:
            builder.add(key, obj.getJsonNumber(key));
            break;
        case TRUE:
        case FALSE:
            builder.add(key, obj.getBoolean(key));
            break;
        case NULL:
            break;
        }
    }
    return builder.build();
}

@Test
public void testRemoveNullJsonObject() {
    String str = ""
        + "{"
        + "   "models":{},"
        + "   "path":["
        + "      {"
        + "         "path":"/web-profiles","
        + "         "operations":["
        + "            {"
        + "               "nickname":"CreateAWebExperienceProfile","
        + "               "type":"","
        + "               "responseMessages":[]"
        + "            }"
        + "         ]"
        + "      }"
        + "   ],"
        + "   "produces":[]"
        + "}";
    JsonObject json = Json.createReader(new StringReader(str)).readObject();
    System.out.println(json);
    JsonObject removed = removeNull(json);
    System.out.println(removed);
    // -> {"path":[{"path":"/web-profiles","operations":[{"nickname":"CreateAWebExperienceProfile"}]}]}
}

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