android - 在Volley中创建Jackson解析的请​​求

我想在截击中创建一个jacksonjsonrequest实现。与大多数请求/响应一样，我的请求/响应将有一个x类型的请求对象和一个y类型的响应对象。
截击请求基类将两者定义为相同的…

public class JacksonRequest<T> extends Request<T>
...
protected Response<T> parseNetworkResponse(NetworkResponse response)

这对我来说没什么意义。我无法想象许多rest请求对请求和响应使用相同的结构。
我是不是遗漏了一些显而易见的东西？

最佳答案

这是我的实现…

public class JacksonRequest<T> extends JsonRequest<T>
{
    private Class<T>    responseType;

    /**
     * Creates a new request.
     *
     * @param method
     *            the HTTP method to use
     * @param url
     *            URL to fetch the JSON from
     * @param requestData
     *            A {@link Object} to post and convert into json as the request. Null is allowed and indicates no parameters will be posted along with request.
     * @param listener
     *            Listener to receive the JSON response
     * @param errorListener
     *            Error listener, or null to ignore errors.
     */
    public JacksonRequest(int method, String url, Object requestData, Class<T> responseType, Listener<T> listener, ErrorListener errorListener)
    {
        super(method, url, (requestData == null) ? null : Mapper.string(requestData), listener, errorListener);
        this.responseType = responseType;
    }

    @Override
    protected Response<T> parseNetworkResponse(NetworkResponse response)
    {
        try
        {
            String jsonString = new String(response.data, HttpHeaderParser.parseCharset(response.headers));
            return Response.success(Mapper.objectOrThrow(jsonString, responseType), HttpHeaderParser.parseCacheHeaders(response));
        }
        catch (Exception e)
        {
            return Response.error(new ParseError(e));
        }
    }
}

上面使用的映射器类只是一个小包装器类…

/**
 * Singleton wrapper class which configures the Jackson JSON parser.
 */
public final class Mapper
{
    private static ObjectMapper MAPPER;

    public static ObjectMapper get()
    {
        if (MAPPER == null)
        {
            MAPPER = new ObjectMapper();

            // This is useful for me in case I add new object properties on the server side which are not yet available on the client.
            MAPPER.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        }

        return MAPPER;
    }

    public static String string(Object data)
    {
        try
        {
            return get().writeValueAsString(data);
        }
        catch (Exception e)
        {
            e.printStackTrace();
            return null;
        }
    }

    public static <T> T objectOrThrow(String data, Class<T> type) throws JsonParseException, JsonMappingException, IOException
    {
        return get().readValue(data, type);
    }

    public static <T> T object(String data, Class<T> type)
    {
        try
        {
            return objectOrThrow(data, type);
        }
        catch (Exception e)
        {
            e.printStackTrace();
            return null;
        }
    }
}