使用谷歌地图API JSON获取纬度和经度有时为NULL [英] Get the lat and lng sometime is NULL with google map api json

问题描述

通过以下代码将大量地址转换为经纬度时，有时结果为空. 我认为原因是过多使用了此网址，因此获取了空值. 如何解决此问题以获取正确的经纬度?

When lots of address be transformed to lat&lng by following code, sometimes the result is null. I think that reason is using this url too much, so getting null value. how do I solve this problem to get correct lat&lng?

String transformerUrl = "http://maps.google.com/maps/api/geocode/json?address=%s&language=zh-TW&sensor=false&region=tw";

private String readAll(Reader rd) throws IOException {
    StringBuilder sb = new StringBuilder();
    int cp;
    while ((cp = rd.read()) != -1) {
        sb.append((char) cp);
    }
    return sb.toString();
}

public String[] getLocationInfoByAddress(String address)
        throws IOException, JSONException {

    String[] latLngStr = new String[2];

    String encodeAddress = URLEncoder.encode(address, "Utf-8");
    String formatAddress = String.format(transformerUrl, encodeAddress);
    InputStream is = new URL(formatAddress).openConnection().getInputStream();
    try {
        BufferedReader rd = new BufferedReader(new InputStreamReader(is,
                Charset.forName("UTF-8")));
        String jsonText = readAll(rd);
        //System.out.println(jsonText);

        try {
            JSONArray arr = new JSONObject(jsonText)
                    .getJSONArray("results");
            for (int i = 0; i < arr.length(); ++i) {
                if (arr.getJSONObject(i).get("geometry") != null) {
                    Object lat =  arr.getJSONObject(i).getJSONObject("geometry").getJSONObject("location").get("lat");
                    Object lng =  arr.getJSONObject(i).getJSONObject("geometry").getJSONObject("location").get("lng") ;

                    latLngStr[0] = lat.toString();
                    latLngStr[1] = lng.toString();

                    break;
                }
            }
        } catch (JSONException e) {
        }


    } finally {
        is.close();
    }

    return latLngStr;
}

推荐答案

检查返回的状态，然后再使用结果.

Check the returned Status before using the result.

Google Maps地理编码网络服务受配额和费率限制.如果您不遵守这些规定，则会获得OVER_QUERY_LIMIT的状态.

The Google Maps Geocoding Web Service is subject to a quota and a rate limit. If you don't comply to those, you will get a status of OVER_QUERY_LIMIT.

如果您没有在您的密钥中添加 URL(我在您的问题中没有看到)，向您的请求添加密钥可能会允许您拥有自己的独立配额(仅在共享服务器上才真正适用).

If you aren't including a key in your URL (which I don't see in your question), adding a key to your request may allow you your own independent quota (only really applicable if you are on a shared server).

如果这没有帮助，则需要限制您的请求以符合配额/费率限制.有关如何在StackOverflow上执行此操作的问题.

If that doesn't help, you need to throttle your requests to comply with quota/rate limit. There are questions on how to do that on StackOverflow.

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