改型：将嵌套的JSON元素解析为列表

Question

{
    "type": "FeatureCollection",
    "features": [
        {
            "type": "Feature",
            "properties": {
                "mag": 6.6,
                "place": "192km ESE of Tadine, New Caledonia"
            }
        },
        {
            "type": "Feature",
            "properties": {
                "mag": 7.5,
                "place": "168km ESE of Tadine, New Caledonia"
            }
        },
        {
            "type": "Feature",
            "properties": {
                "mag": 6,
                "place": "155km ESE of Tadine, New Caledonia"
            }
        }
    ]
}

public class Earthquake {
    @SerializedName("mag")
    private double magnitude;
    @SerializedName("place")
    private String location;

    public   Earthquake(double magnitude, String location) {
        this.magnitude = magnitude;
        this.location = location;
    }
    // getters
}

public class EarthquakeDeserializer implements JsonDeserializer<ArrayList<Earthquake>> {

    @Override
    public ArrayList<Earthquake> deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
        // get list of "features"
        JsonElement features = json.getAsJsonObject().get("features");

        JsonArray earthquakeElements = new JsonArray();
        for (JsonElement feature : features.getAsJsonArray()){
            JsonElement properties = feature.getAsJsonObject().get("properties");
            earthquakeElements.add(properties);
        }

        Type listType = new TypeToken<ArrayList<Earthquake>>(){}.getType();

        return new Gson().fromJson(earthquakeElements, listType);
    }
}

你知道这是怎么回事吗？

Answer 1

您可以为Json创建这种POJO类，无论您只想要响应体的单个部分，您都需要为整个响应创建POJO，并且需要从该POJO中获得适当的属性。->

这是您的主要json对象->

public class Example {

    @SerializedName("type")
    @Expose
    private String type;
    @SerializedName("features")
    @Expose
    private List<Feature> features = null;

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

    public List<Feature> getFeatures() {
        return features;
    }

    public void setFeatures(List<Feature> features) {
        this.features = features;
    }

}

这是您的特性类->

package com.example;

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Feature {

    @SerializedName("type")
    @Expose
    private String type;
    @SerializedName("properties")
    @Expose
    private Properties properties;

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

    public Properties getProperties() {
        return properties;
    }

    public void setProperties(Properties properties) {
        this.properties = properties;
    }

}

package com.example;

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Properties {

    @SerializedName("mag")
    @Expose
    private Integer mag;
    @SerializedName("place")
    @Expose
    private String place;

    public Integer getMag() {
        return mag;
    }

    public void setMag(Integer mag) {
        this.mag = mag;
    }

    public String getPlace() {
        return place;
    }

    public void setPlace(String place) {
        this.place = place;
    }

}