Gson反序列化跳过一个引号

Question

我必须反序列化JSON。为此，我使用GSON 库。我正在构建一个 Web 应用程序。用户填写他想飞的地方，然后将查询发送到API并返回结果。

让我们用一个响应的例子：

{"success":true,"data":{"WAW":{"0":{"price":153,"airline":"LO","flight_number":678,"departure_at":"2019-08-05T17:40:00Z","return_at":"2019-08-20T14:35:00Z","expires_at":"2019-05-24T20:55:02Z"},"1":{"price":126,"airline":"A3","flight_number":881,"departure_at":"2019-11-21T11:00:00Z","return_at":"2019-11-26T16:05:00Z","expires_at":"2019-05-27T13:39:23Z"},"2":{"price":171,"airline":"KL","flight_number":900,"departure_at":"2019-09-12T02:40:00Z","return_at":"2019-09-18T17:30:00Z","expires_at":"2019-05-27T10:40:40Z"},"3":{"price":235,"airline":"B2","flight_number":972,"departure_at":"2019-06-12T07:20:00Z","return_at":"2019-06-18T17:30:00Z","expires_at":"2019-05-26T12:31:22Z"},"4":{"price":596,"airline":"TK","flight_number":422,"departure_at":"2019-06-20T00:10:00Z","return_at":"2019-06-24T13:05:00Z","expires_at":"2019-05-26T08:08:21Z"}}},"error":null,"currency":"EUR"}

我以这种方式创建了一个类：http://pojo.sodhanalibrary.com

问题是总是有到达地的名称。在这种情况下WAW = Warsaw。

gsonConvert.gson(output).getData().getWAW().getFirst().getAirline()

我想避免它，因为到达地点将取决于用户的选择。

Answer 1

您应该能够将您的data 属性简化为输入：Map<String, Map<String, Flight>>。其中FlightPOJO 代表给定的航班。模型可能如下所示：

class FlightResponse {

    private boolean success;
    private Map<String, Map<String, Flight>> data;
    private String error;
    private String currency;

    public Map<String, Flight> getFlatData() {
        return data.entrySet()
                .stream()
                .collect(HashMap::new, (m, e) -> m.putAll(e.getValue()), Map::putAll);
    }

    // getters, setters, toString
}

class Flight {

    private BigDecimal price;
    private String airline;

    @SerializedName("flight_number")
    private int flightNumber;

    @SerializedName("departure_at")
    private String departureAt;

    @SerializedName("return_at")
    private String returnAt;

    @SerializedName("expires_at")
    private String expiresAt;

    // getters, setters, toString
}

以及如何解析JSON 的示例：

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.annotations.SerializedName;

import java.io.File;
import java.io.FileReader;
import java.math.BigDecimal;
import java.util.HashMap;
import java.util.Map;

public class GsonApp {

    public static void main(String[] args) throws Exception {
        File jsonFile = new File("./resource/test.json").getAbsoluteFile();

        Gson gson = new GsonBuilder().create();

        FlightResponse flightResponse = gson.fromJson(new FileReader(jsonFile), FlightResponse.class);

        flightResponse.getFlatData().forEach((k, v) -> {
            System.out.println(k + " => " + v);
        });
    }
}

上面的代码打印：

0 => Flight{price=153, airline='LO', flightNumber=678, departureAt='2019-08-05T17:40:00Z', returnAt='2019-08-20T14:35:00Z', expiresAt='2019-05-24T20:55:02Z'}
1 => Flight{price=126, airline='A3', flightNumber=881, departureAt='2019-11-21T11:00:00Z', returnAt='2019-11-26T16:05:00Z', expiresAt='2019-05-27T13:39:23Z'}
2 => Flight{price=171, airline='KL', flightNumber=900, departureAt='2019-09-12T02:40:00Z', returnAt='2019-09-18T17:30:00Z', expiresAt='2019-05-27T10:40:40Z'}
3 => Flight{price=235, airline='B2', flightNumber=972, departureAt='2019-06-12T07:20:00Z', returnAt='2019-06-18T17:30:00Z', expiresAt='2019-05-26T12:31:22Z'}
4 => Flight{price=596, airline='TK', flightNumber=422, departureAt='2019-06-20T00:10:00Z', returnAt='2019-06-24T13:05:00Z', expiresAt='2019-05-26T08:08:21Z'}

另见：

• Flatten a Map> to Map with stream and lambda