杰克逊+建筑师模式？ [英] Jackson + Builder Pattern?

问题描述

我希望Jackson使用以下构造函数对类进行反序列化：

I'd like Jackson to deserialize a class with the following constructor:

public Clinic(String name, Address address)

反序列化第一个参数很容易。问题是地址被定义为：

Deserializing the first argument is easy. The problem is that Address is defined as:

public class Address {
  private Address(Map<LocationType, String> components)
  ...

  public static class Builder {
    public Builder setCity(String value);
    public Builder setCountry(String value);
    public Address create();
  }
}

并且构造如下： new Address.Builder（）。setCity（foo）。setCountry（bar）。create（）;

是否有从杰克逊获得键值对的方法，以便自己构建地址？或者，有没有办法让Jackson使用Builder类本身？

Is there a way to get key-value pairs from Jackson in order to construct the Address myself? Alternatively, is there a way to get Jackson to use the Builder class itself?

推荐答案

我最终使用@JsonDeserialize实现了这个如下：

I ended up implementing this using the @JsonDeserialize as follows:

@JsonDeserialize(using = JacksonDeserializer.class)
public class Address
{...}

@JsonCachable
static class JacksonDeserializer extends JsonDeserializer<Address>
{
    @Override
    public Address deserialize(JsonParser parser, DeserializationContext context)
        throws IOException, JsonProcessingException
    {
        JsonToken token = parser.getCurrentToken();
        if (token != JsonToken.START_OBJECT)
        {
            throw new JsonMappingException("Expected START_OBJECT: " + token, parser.getCurrentLocation());
        }
        token = parser.nextToken();
        Builder result = new Builder();
        while (token != JsonToken.END_OBJECT)
        {
            if (token != JsonToken.FIELD_NAME)
            {
                throw new JsonMappingException("Expected FIELD_NAME: " + token, parser.getCurrentLocation());
            }
            LocationType key = LocationType.valueOf(parser.getText());

            token = parser.nextToken();
            if (token != JsonToken.VALUE_STRING)
            {
                throw new JsonMappingException("Expected VALUE_STRING: " + token, parser.getCurrentLocation());
            }
            String value = parser.getText();

            // Our Builder allows passing key-value pairs
            // alongside the normal setter methods.
            result.put(key, value);
            token = parser.nextToken();
        }
        return result.create();
    }
}

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