如何在JavaME中获取最新的汇率数据

我是JavaMe新手，我想创建一个可以在线获取特定货币最新汇率的应用程序，我如何才能做到这一点

我已经能够创建HttpConnection对象并从URL检索数据，但它不适用于google

我在这里看到了一个问题的例子，题为。然而，如果我在移动应用程序上尝试它，它将一无所获。 我怎样才能解决这个问题

String url = "http://www.google.com/ig/calculator?hl=en&q=1USD%3D%3FCAD";//test URL
c = (HttpConnection)Connector.open(url);
s = c.openInputStream();//open an input stream
if( l != -1 ) {
  for (i =0 ; i < l ; i++ )
  if((ch = s.read()) != -1){
     b.append((char) ch);
    }
}
stringItem2.setText("\n " + b.toString());

我能够获得网站数据，但是

String url = "http://www.google.com/ig/calculator?hl=en&q=1USD%3D%3FCAD";

我没有得到任何东西

我会用它来检索最新的汇率，但如果你每天查询超过10次，你必须为此支付29.99英镑。页面的文档部分解释了如何使用API。例如，检索您使用的美元兑欧元汇率。 如果您将其输入浏览器并查看源，您将看到检索到的响应。响应是JSON格式的

您需要使用类似的方法将JSON数据转换为Java对象。执行此操作的代码应该非常简单，例如：

    URL url = new URL("http://xurrency.com/api/usd/eur/1");
    URLConnection yc = url.openConnection();
    BufferedReader in = new BufferedReader(
                            new InputStreamReader(
                            yc.getInputStream()));
    String jsonObject = "";
    String line;
    while ((line = in.readLine()) != null) 
        jsonObject += line;

    in.close();
    Gson gson = new Gson();
    ExchangeRate = gson.fromJson(jsonObject, ExchangeRate.class);

ExchnageRate类是一个定制类，用于封装从这个JSON API检索到的数据

您可以使用正在使用的链接使上述代码正常工作。请尝试以下代码：

  import com.google.gson.Gson;
  import java.io.BufferedReader;
  import java.io.InputStreamReader;
  import java.net.URL;
  import java.net.URLConnection;

  public class Main {
    public static void main(String[] args) throws Exception {
        URL url = new URL("http://www.google.com/ig/calculator?hl=en&q=1USD%3D%3FCAD");
        URLConnection yc = url.openConnection();
        BufferedReader in = new BufferedReader(
                            new InputStreamReader(
                            yc.getInputStream()));
        String jsonObject = "";
        String line;
        while ((line = in.readLine()) != null) 
            jsonObject += line;

        in.close();
        System.out.println(jsonObject);
        Gson gson = new Gson();
        GoogleCurrency another = gson.fromJson(jsonObject, GoogleCurrency.class);
        another.print();
    }

  }


  public class GoogleCurrency {
     private String lhs;
     private String rhs;
     private String error;
     private String icc;

   public GoogleCurrency() {
    lhs = "0 U.S Dollar";
    rhs = "0 U.S Dollar";
    error = "true";
    icc = "false";
   }

   public GoogleCurrency(String lhs,String rhs,String error,String icc) {
    this.lhs = lhs;
    this.rhs = rhs;
    this.error = error;
    this.icc = icc;
   }

   public void print() {
    System.out.println(lhs + " = " + rhs);
   }
 }

---

请查找下面的代码，该代码返回json响应以获取转换率。

    HttpClient client = new HttpClient();       

    NameValuePair arg1 = new NameValuePair("method","runJob");

    //Change your currency types here in which you would want to convert

    NameValuePair arg2 = new NameValuePair("from","USD");
    NameValuePair arg3 = new NameValuePair("to", "PKR");

    //getting the method
    GetMethod method = new GetMethod("http://rate-exchange.appspot.com/currency");
    method.setQueryString(new NameValuePair[]{arg1, arg2, arg3});

    //executes the link
    client.executeMethod(method);

    //getting response in string
    JSONObject obj = new JSONObject(method.getResponseBodyAsString());

    //getting rate from the json response
    double rate = obj.getDouble("rate");

    //closing conncetion
    method.releaseConnection();     


    //returning value
    return rate;

---

没有要检查的代码？或者你只是想让我们帮你写下来？什么不管用？你从哪里获得汇率数据？如果你需要帮助，请告诉我们代码。好的，非常感谢。这是否意味着谷歌不可能做到这一点，因为它看起来简单得多？我以前从未见过谷歌计算器，但它会工作得很好。这只是一个将此URL中的数据用于你的应用程序是否违反了谷歌规定的使用条款的问题。好的，我听说谷歌之前就存在使用条款问题，这种方法对我很有效，非常感谢，你解决了我的问题。

    HttpClient client = new HttpClient();       

    NameValuePair arg1 = new NameValuePair("method","runJob");

    //Change your currency types here in which you would want to convert

    NameValuePair arg2 = new NameValuePair("from","USD");
    NameValuePair arg3 = new NameValuePair("to", "PKR");

    //getting the method
    GetMethod method = new GetMethod("http://rate-exchange.appspot.com/currency");
    method.setQueryString(new NameValuePair[]{arg1, arg2, arg3});

    //executes the link
    client.executeMethod(method);

    //getting response in string
    JSONObject obj = new JSONObject(method.getResponseBodyAsString());

    //getting rate from the json response
    double rate = obj.getDouble("rate");

    //closing conncetion
    method.releaseConnection();     


    //returning value
    return rate;