javax.json：将新的JsonNumber添加到现有的JsonObject

I want to add properties to an existing instance of JsonObject. If this property is boolean, this is quite easy:

我想将属性添加到现有的JsonObject实例。如果此属性是布尔值，这很容易：

JsonObject jo = ....;
jo.put("booleanProperty", JsonValue.TRUE);

However, I also want to add a JsonNumber but I couldn't find a way to create an instance of JsonNumber. Here's what I could do:

但是，我还想添加一个JsonNumber但是我找不到创建JsonNumber实例的方法。这是我能做的：

JsonObjectBuilder job = Json.createObjectBuilder();
JsonNumber jn = job.add("number", 42).build().getJsonNumber("number");
jo.put("numberProperty", jn);

But I couldn't think of a more dirty way to accomplish my task. So - is there are more direct, cleaner approach to add a JsonNumber to an existing instance of JsonObject?

但我想不出一个更脏的方式来完成我的任务。那么 - 是否有更直接，更清晰的方法将JsonNumber添加到现有的JsonObject实例中？

2 个解决方案

#1

Okay, I just figured it out myself: You can't.

好吧，我只是想出了自己：你做不到。

JsonObject is supposed to be immutable. Even if JsonObject.put(key, value) exists, at runtime this will throw an UnsupportedOperationException. So if you want to add a key/value-pair to an existing JsonObject you'll need something like

JsonObject应该是不可变的。即使JsonObject.put（key，value）存在，在运行时也会抛出UnsupportedOperationException。因此，如果要为现有的JsonObject添加键/值对，则需要类似的东西

private JsonObjectBuilder jsonObjectToBuilder(JsonObject jo) {
    JsonObjectBuilder job = Json.createObjectBuilder();

    for (Entry<String, JsonValue> entry : jo.entrySet()) {
        job.add(entry.getKey(), entry.getValue());
    }

    return job;
}

and then use it with

然后用它

JsonObject jo = ...;
jo = jsonObjectToBuilder(jo).add("numberProperty", 42).build();

#2

JsonObject is immutable but can be copied into a JsonObjecBuilder using lambdas.

JsonObject是不可变的，但可以使用lambdas复制到JsonObjecBuilder中。

JsonObject source = ...
JsonObjectBuilder target = Json.createObjectBuilder();
source.forEach(target::add); // copy source into target
target.add("name", "value"); // add or update values
JsonObject destination = target.build(); // build destination

#1