[英]Jackson: Deserialize JSON-Array in different attributes of an object
I need to decode the following JSON-Structure: 我需要解码以下JSON结构:
{
"id":1
"categories": [
value_of_category1,
value_of_category2,
value_of_category3
]
}
The object I am trying to deserialize into is of the following class: 我尝试反序列化的对象属于以下类:
class MyClass {
public Integer id;
public Category1 category1;
public Category2 category2;
public Category3 category3;
...
}
public enum Category1{
...
}
public enum Category2{
...
}
public enum Category3{
...
}
In the JSON the first entry of the categories-Array is always a value of the enum Category1, the second entry is always a value of the enum Category2 and the third entry is always a value of the enum Category3. 在JSON中,类别数组的第一个条目始终是枚举Category1的值,第二个条目始终是枚举Category2的值,而第三个条目始终是枚举Category3的值。
How can I deserialize this JSON into my class structure using Jackson? 如何使用Jackson将此JSON反序列化为类结构?
You can create your custom deserializer by extending the JsonDeserializer<T>
class. 您可以通过扩展
JsonDeserializer<T>
类来创建自定义解串器。
Here is a sample implementation to fit your needs 这是一个适合您需求的示例实现
public class MyClassDeserializer extends JsonDeserializer<MyClass>{
@Override
public MyClass deserialize(JsonParser jp, DeserializationContext ctxt)
throws IOException, JsonProcessingException {
JsonNode node = jp.getCodec().readTree(jp);
int id = (Integer) ((IntNode) node.get("id")).numberValue();
JsonNode categories = node.get("categories");
Iterator<JsonNode> iter = categories.elements();
while(iter.hasNext()){
//create Category object based on an incrementing counter
}
MyClass myClass = //compose myClass from the values deserialized above.
return myClass;
}
}
To use it, you just have to annotate MyClass
with @JsonDeserialize
pointing to your custom deserializer. 要使用它,您只需用指向您的自定义反序列化器的
@JsonDeserialize
注释MyClass
。
@JsonDeserialize(using = MyClassDeserializer.class)
public class MyClass {
private Integer id;
private Category1 category1;
private Category2 category2;
private Category3 category3;
}
Not related, but as a good practice, make all your fields private then expose public setters and getters in order to control the fields of the class. 不相关,但是作为一种好习惯,请将您所有的字段都设为私有,然后公开公共的setter和getter以便控制类的字段。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.