为什么我无法使用 Jackson Java 库解包和序列化 Java 映射？
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Why I'm not able to unwrap and serialize a Java map using the Hymanson Java library?
提问by Suren Raju
My bean looks like this:
我的豆子看起来像这样：
class MyBean {
private @JsonUnwrapped HashMap<String, String> map = new HashMap<String, String>();
private String name;
public HashMap<String, String> getMap() {
return map;
}
public void setMap(HashMap<String, String> map) {
this.map = map;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
While I'm serializing the bean using the following code:
当我使用以下代码序列化 bean 时：
MyBean bean = new MyBean();
HashMap<String, String> map = new HashMap<String, String>();;
map.put("key1", "value1");
map.put("key2", "value2");
bean.setMap(map);
bean.setName("suren");
ObjectMapper mapper = new ObjectMapper();
System.out.println("\n"+mapper.writeValueAsString(bean));
I'm getting result like this:
我得到这样的结果：
{"map":{"key2":"value2","key1":"value1"},"name":"suren"}
but
但
{"key2":"value2","key1":"value1","name":"suren"}
is expected per the HymansonFeatureUnwrapping documentation. Why am I not getting the unwrapped result?
根据HymansonFeatureUnwrapping 文档预计。为什么我没有得到解包的结果？
采纳答案by Hari Menon
@JsonUnwrappeddoesn't work for maps, only for proper POJOs with getters and setters. For maps, You should use @JsonAnyGetterand @JsonAnySetter(available in Hymanson version >= 1.6).
@JsonUnwrapped不适用于地图，仅适用于具有 getter 和 setter 的适当 POJO。对于地图，您应该使用@JsonAnyGetter和@JsonAnySetter（在 Hymanson 版本 >= 1.6 中可用）。
In your case, try this:
在你的情况下，试试这个：
@JsonAnySetter
public void add(String key, String value) {
map.put(key, value);
}
@JsonAnyGetter
public Map<String,String> getMap() {
return map;
}
That way, you can also directly add properties to the map, like add('abc','xyz')will add a new key abcto the map with value xyz.
这样，您也可以直接向地图添加属性，例如add('abc','xyz')将一个新的键添加abc到地图中，并带有 value xyz。
回答by M. Justin
There is currently an an open issueat the Hymanson project to allow support for @JsonUnwrappedon Maps. It is not tagged as being in the upcoming 2.10 or 3.x versions of Hymanson, so it does not look like it's on the near-term feature roadmap.
Hymanson 项目目前有一个未解决的问题，允许@JsonUnwrapped在地图上提供支持。它没有被标记为在即将到来的 2.10 或 3.x 版本的 Hymanson 中，所以它看起来不像是在近期的功能路线图上。
Until this feature is supported, the workaround about using @JsonAnySetter/@JsonAnyGetterproposed in another answerappears to be the way to go.
在支持此功能之前，在另一个答案中使用@JsonAnySetter/@JsonAnyGetter建议的解决方法似乎是可行的方法。
