1、 从Transaction 的TransactionReceipt属性中得到接收的数据，并以base64编码；
2、创建JSON对象，字典格式，单键值对，键名为“receiptdata”，值为上一次编码的数据，效果：
{"receipt-data":"base64编码之后的数据"}
3、发送HTTP POST请求，将数据发送到App Store ，其地址为：https://buy.itunes.apple.com/verifyReceipt
4、App Store的返回值也是一个JSON格式对象，包括两个键值对：
{
"status" : 0,
"receipt" : { … }
}
说明：
如果status的值为0，就说明该receipt为有效的，否则就是无效的。
public int verifyReceipt( byte[] receipt) {int status = -1;//This is the URL of the REST webservice in iTunes App StoreURL url = new URL("https://buy.itunes.apple.com/verifyReceipt");//make connection, use post modeHttpsURLConnection connection = (HttpsURLConnection) url.openConnection();connection.setRequestMethod("POST");connection.setDoOutput(true);connection.setAllowUserInteraction(false);//Encode the binary receipt data into Base 64//Here I'm using org.apache.commons.codec.binary.Base64 as an encoder, since commons-codec is already in Grails classpathBase64 encoder = new Base64();String encodedReceipt = new String(encoder.encode(receipt));//Create a JSON query object//Here I'm using Grails' org.codehaus.groovy.grails.web.json.JSONObjectMap map = new HashMap();map.put("receipt-data", encodedReceipt);JSONObject jsonObject = new JSONObject(map);//Write the JSON query object to the connection output streamPrintStream ps = new PrintStream(connection.getOutputStream());ps.print(jsonObject.toString());ps.close();//Call the serviceBufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream()));//Extract responseString str;StringBuffer sb = new StringBuffer();while ((str = br.readLine()) != null) {sb.append(str);sb.append("/n");}br.close();String response = sb.toString();//Deserialize responseJSONObject result = new JSONObject(response);status = result.getInt("status");if (status == 0) {//provide content} else {//signal error, throw an exception, do your stuff honey!}return status ;}
验证的方式也可以采用HTTP协议：HttpClient，下载httpcomponents-client，然后导入lib里的几个jar包。
这也是一种方式，不再进行多余的说明了。所谓条条道路通“苹果”。