android - jackson 2 反序列化

Question

我在使用 google geocoding api 时遇到问题。例如，使用此网址 http://maps.google.com/maps/api/geocode/json?latlng=47.3195254,5.0430687&sensor=true ，我想用 jackson 2 解析 json 来创建 POJO。

所以我的课是

public class GeocoderResult {

@JsonProperty("results") private List<GeocoderGoog> geocoder;
@JsonProperty("status") private String status;

public List<GeocoderGoog> getGeocoder() {
    return geocoder;
}
public String getStatus() {
    return status;
}

}

为了反序列化json，我使用

HttpURLConnection connection = (HttpURLConnection) new URL(baseUrl).openConnection();
ObjectMapper mapper = new ObjectMapper();
// disable exceptions when there is unknown properties
mapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
int statusCode = connection.getResponseCode();
Log.d(Constants.D_TAG, "Status : "+statusCode);
if (statusCode == HttpURLConnection.HTTP_OK) {  // 200
    InputStream is = new BufferedInputStream(connection.getInputStream());
    status = (Status) mapper.readValue(is, GeocoderResult.class);
}

我有以下错误:

09:38:42.737 Thread-24889 An exception occurred during request network execution :Unexpected close marker '}': expected ']' (for ROOT starting at [Source: java.io.BufferedInputStream@428a1840; line: 1, column: 0])                                       
 at [Source: java.io.BufferedInputStream@428a1840; line: 2, column: 14]
 com.fasterxml.jackson.core.JsonParseException: Unexpected close marker '}': expected ']' (for ROOT starting at [Source: java.io.BufferedInputStream@428a1840; line: 1, column: 0])

我不明白问题出在哪里...

ps : 我使用 jackson-core, jackson-databind 和 jackson-annotations 2.1.4

Answer 1

我是 Jackson 的粉丝，我可以说你让我很好奇。我使用了您公开的 URL 并使其像下面一样工作。 使用当前 API 版本:2.2.3

模型类:

地理编码器结果

public class GeocoderResult {

    @JsonProperty("results")
    private ArrayList<GeocoderGoog> geocoder;

    @JsonProperty("status")
    private String status;

    public ArrayList<GeocoderGoog> getGeocoder() {
        return geocoder;
    }

    public String getStatus() {
        return status;
    }
}

GeocoderGoog

public class GeocoderGoog {

    @JsonProperty("address_components")
    private ArrayList<AddressComponent> addressComponents;

    @JsonProperty("formatted_address")
    private String formattedAddress;

    private ArrayList<String> types;

    private Geometry geometry;

    public ArrayList<AddressComponent> getAddressComponents() {
        return addressComponents;
    }

    public String getFormattedAddress() {
        return formattedAddress;
    }

    public ArrayList<String> getTypes() {
        return types;
    }

    public Geometry getGeometry() {
        return geometry;
    }

}

地址组件

public class AddressComponent {
    @JsonProperty("long_name")
    private String longName;

    @JsonProperty("short_name")
    private String shortName;

    private ArrayList<String> types;

    public String getLongName() {
        return longName;
    }

    public String getShortName() {
        return shortName;
    }

    public ArrayList<String> getTypes() {
        return types;
    }

}

在其他类中使用的坐标

public class Coordinates {
    private double lat;
    private double lng;

    public double getLat() {
        return lat;
    }

    public void setLat(double lat) {
        this.lat = lat;
    }

    public double getLng() {
        return lng;
    }

    public void setLng(double lng) {
        this.lng = lng;
    }

}

和一个带有Viewport的Geometry:

public class Geometry {
    private Coordinates location;

    @JsonProperty("location_type")
    private String locationType;

    private ViewPort viewport;

    public Coordinates getLocation() {
        return location;
    }

    public String getLocationType() {
        return locationType;
    }

    public ViewPort getViewport() {
        return viewport;
    }

    public static class ViewPort {
        private Coordinates northeast;
        private Coordinates southwest;

        public Coordinates getNortheast() {
            return northeast;
        }

        public Coordinates getSouthwest() {
            return southwest;
        }

    }
}

总结一下——对我来说这从第一次尝试开始就成功了:

protected void performJackson() {
    new AsyncTask<Void, Void, Void>() {
        @Override
        protected Void doInBackground(Void... params) {
            try {
                String baseUrl = "http://maps.google.com/maps/api/geocode/json?latlng=47.3195254,5.0430687&sensor=true";
                HttpURLConnection connection = (HttpURLConnection) new URL(baseUrl).openConnection();
                ObjectMapper mapper = new ObjectMapper();
                // disable exceptions when there is unknown properties
                mapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
                int statusCode = connection.getResponseCode();
                Log.d("SJackson", "Status : " + statusCode);
                if (statusCode == HttpURLConnection.HTTP_OK) { // 200
                    InputStream is = new BufferedInputStream(connection.getInputStream());
                    GeocoderResult result = mapper.readValue(is, GeocoderResult.class);
                    Log.d("SJackson", "Done: " + (result != null));
                }
            } catch (Exception ex) {
                Log.e("SJackson", null, ex);
            }

            return null;
        }
    }.execute();
}