Gson

Question

我对REST和JSON有相当丰富的经验，但我想不出一种方法将一些JSON读取为Java对象。

响应如下：https://api.kraken.com/0/public/OHLC?pair=XBTCZEUR&interval=60

请注意其中一个名称(相关数据)是如何依赖于查询参数的。我不确定如何为Gson创建用于反序列化的Java对象，因为其中一个变量名可能会更改。

我想也许可以使用JsonReader以流的方式读取响应，但当我这样做时，我得到了403错误响应。

有什么想法吗？

Answer 1

如果您不知道响应将包含什么，您可以始终使用map类的实现来传递给gson，正如我在这里尝试演示的那样：

public class RestResponse {

    private boolean success;
    private String errorDescription;
    private Map<String, Object> data;

    private static Gson GSON = new Gson();

    private RestResponse()
    {
        data = new HashMap<String, Object>();
    }

    public boolean isSuccess() {
        return success;
    }

    private void setSuccess(boolean success) {
        this.success = success;
    }

    public String getErrorDescription() {
        return errorDescription;
    }

    private void setErrorDescription(String errorDescription) {
        this.errorDescription = errorDescription;
    }

    public Object getData(String... nestedKeys)
    {
        List<String> nestedKeysAsList = Arrays.asList(nestedKeys);
        return getData(nestedKeysAsList);
    }

    public Object getData(List<String> nestedKeys)
    {
        String firstKey = nestedKeys.get(0);
        if(!data.containsKey(firstKey))
            throw new IllegalArgumentException("Key not found");

        Object mapValue = data.get(firstKey);

        if(!(mapValue instanceof Map))
            return mapValue;

        String finalKey = nestedKeys.get(nestedKeys.size()-1);
        if(nestedKeys.size() > 2)
        {
            for(String nextKey : nestedKeys.subList(1,nestedKeys.size()-1))
            {
                Map<String,Object> tempMap = (Map)mapValue;
                mapValue = tempMap.get(nextKey);
            }
        }

        Map<String,Object> tempMap = (Map)mapValue;
        return tempMap.get(finalKey);
    }

    private Map<String, Object> getData() {
        return data;
    }

    private void setData(Map<String, Object> map){
        this.data = map;
    }

    public static RestResponse createUnsuccessfulResponse(Exception e)
    {
        return createUnsuccessfulResponse(e.getMessage());
    }

    public static RestResponse createUnsuccessfulResponse(String reason)
    {
        RestResponse res = new RestResponse();
        res.setSuccess(false);
        res.setErrorDescription(reason);

        return res;
    }

    public static RestResponse createSuccessfulResponse(String jsonString)
    {
        Map<String, Object> jsonToDataMap = GSON.fromJson(jsonString, Map.class);
        return createSuccessfulResponseByMap(jsonToDataMap);
    }

    private static RestResponse createSuccessfulResponseByMap(Map<String, Object> jsonToDataMap)
    {
        RestResponse res = new RestResponse();
        res.setSuccess(true);
        res.setErrorDescription("Success");
        res.setData(jsonToDataMap);

        return res;
    }
}

用法示例可以在这里找到：

https://github.com/cgunduz/btcenter/blob/master/src/main/java/com/cemgunduz/utils/entity/RestResponse.java