javaでAmozon Product Advertising API
Amozon Product Advertising APIを使ってみる。
Product Advertising API Signed Requests Sample Code - Java REST/QUERY : Sample Code & Libraries : Amazon Web Services
ここからサンプルコードをダウンロードする。Codec – Home
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Codec 1.10 (mirrors) requires Java 1.6を選択(最新のもの)。
commons-codec-1.10-bin.zipをダウンロードする。commons-codec-1.9.jar
commons-codec-1.9-javadoc.jar
commons-codec-1.9-sources.jar
をeclipseに入れる。
導入方法→commons-langを入れる方法 - プログラミングMEMO
エラー
titleがnullになってしまいエラーが出る。
解決方法
AssociateTagがないのが原因みたい?
AssociateTagはアソシエイトIDの事。
AssociateTagが必要なところに追加してみたら解決した。
ItemLookupSample.java
package test; import java.util.HashMap; import java.util.Map; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import org.w3c.dom.Document; import org.w3c.dom.Node; /* * This class shows how to make a simple authenticated ItemLookup call to the * Amazon Product Advertising API. * * See the README.html that came with this sample for instructions on * configuring and running the sample. */ public class ItemLookupSample { /* * Your AWS Access Key ID, as taken from the AWS Your Account page. */ private static final String AWS_ACCESS_KEY_ID = "自分のID"; /* * Your AWS Secret Key corresponding to the above ID, as taken from the AWS * Your Account page. */ private static final String AWS_SECRET_KEY = "自分のID"; private static final String ASSOCIATE_TAG = "自分のID-22"; //ここに追加 /* * Use one of the following end-points, according to the region you are * interested in: * * US: ecs.amazonaws.com * CA: ecs.amazonaws.ca * UK: ecs.amazonaws.co.uk * DE: ecs.amazonaws.de * FR: ecs.amazonaws.fr * JP: ecs.amazonaws.jp * */ private static final String ENDPOINT = "ecs.amazonaws.jp"; /* * The Item ID to lookup. The value below was selected for the US locale. * You can choose a different value if this value does not work in the * locale of your choice. */ private static final String ITEM_ID = "0545010225"; public static void main(String[] args) { /* * Set up the signed requests helper */ SignedRequestsHelper helper; try { helper = SignedRequestsHelper.getInstance(ENDPOINT, AWS_ACCESS_KEY_ID, AWS_SECRET_KEY, ASSOCIATE_TAG); //ここに追加 } catch (Exception e) { e.printStackTrace(); return; } String requestUrl = null; String title = null; /* The helper can sign requests in two forms - map form and string form */ /* * Here is an example in map form, where the request parameters are stored in a map. */ System.out.println("Map form example:"); Map<String, String> params = new HashMap<String, String>(); params.put("Service", "AWSECommerceService"); params.put("Version", "2009-03-31"); params.put("Operation", "ItemLookup"); params.put("ItemId", ITEM_ID); params.put("ResponseGroup", "Small"); params.put("AssociateTag", ASSOCIATE_TAG); //ここに追加 requestUrl = helper.sign(params); System.out.println("Signed Request is \"" + requestUrl + "\""); title = fetchTitle(requestUrl); System.out.println("Signed Title is \"" + title + "\""); System.out.println(); /* Here is an example with string form, where the requests parameters have already been concatenated * into a query string. */ System.out.println("String form example:"); String queryString = "Service=AWSECommerceService&Version=2009-03-31&Operation=ItemLookup&ResponseGroup=Small&ItemId=" + ITEM_ID; requestUrl = helper.sign(queryString); System.out.println("Request is \"" + requestUrl + "\""); title = fetchTitle(requestUrl); System.out.println("Title is \"" + title + "\""); System.out.println(); } /* * Utility function to fetch the response from the service and extract the * title from the XML. */ private static String fetchTitle(String requestUrl) { String title = null; try { DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); DocumentBuilder db = dbf.newDocumentBuilder(); Document doc = db.parse(requestUrl); Node titleNode = doc.getElementsByTagName("Title").item(0); title = titleNode.getTextContent(); } catch (Exception e) { throw new RuntimeException(e); } return title; } }
SignedRequestsHelper.java
package test; import java.io.UnsupportedEncodingException; import java.net.URLDecoder; import java.net.URLEncoder; import java.security.InvalidKeyException; import java.security.NoSuchAlgorithmException; import java.text.DateFormat; import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.SortedMap; import java.util.TimeZone; import java.util.TreeMap; import javax.crypto.Mac; import javax.crypto.spec.SecretKeySpec; import org.apache.commons.codec.binary.Base64; /** * This class contains all the logic for signing requests * to the Amazon Product Advertising API. */ public class SignedRequestsHelper { /** * All strings are handled as UTF-8 */ private static final String UTF8_CHARSET = "UTF-8"; /** * The HMAC algorithm required by Amazon */ private static final String HMAC_SHA256_ALGORITHM = "HmacSHA256"; /** * This is the URI for the service, don't change unless you really know * what you're doing. */ private static final String REQUEST_URI = "/onca/xml"; /** * The sample uses HTTP GET to fetch the response. If you changed the sample * to use HTTP POST instead, change the value below to POST. */ private static final String REQUEST_METHOD = "GET"; private String endpoint = null; private String awsAccessKeyId = null; private String awsSecretKey = null; private String associateTag = null; //ここに追加 private SecretKeySpec secretKeySpec = null; private Mac mac = null; /** * You must provide the three values below to initialize the helper. * * @param endpoint Destination for the requests. * @param awsAccessKeyId Your AWS Access Key ID * @param awsSecretKey Your AWS Secret Key * @param associateTag Your Associate Tag //ここに追加 */ public static SignedRequestsHelper getInstance( String endpoint, String awsAccessKeyId, String awsSecretKey, String associateTag //ここに追加 ) throws IllegalArgumentException, UnsupportedEncodingException, NoSuchAlgorithmException, InvalidKeyException { if (null == endpoint || endpoint.length() == 0) { throw new IllegalArgumentException("endpoint is null or empty"); } if (null == awsAccessKeyId || awsAccessKeyId.length() == 0) { throw new IllegalArgumentException("awsAccessKeyId is null or empty"); } if (null == awsSecretKey || awsSecretKey.length() == 0) { throw new IllegalArgumentException("awsSecretKey is null or empty"); } SignedRequestsHelper instance = new SignedRequestsHelper(); instance.endpoint = endpoint.toLowerCase(); instance.awsAccessKeyId = awsAccessKeyId; instance.awsSecretKey = awsSecretKey; instance.associateTag = associateTag; //ここに追加 byte[] secretyKeyBytes = instance.awsSecretKey.getBytes(UTF8_CHARSET); instance.secretKeySpec = new SecretKeySpec(secretyKeyBytes, HMAC_SHA256_ALGORITHM); instance.mac = Mac.getInstance(HMAC_SHA256_ALGORITHM); instance.mac.init(instance.secretKeySpec); return instance; } /** * The construct is private since we'd rather use getInstance() */ private SignedRequestsHelper() {} /** * This method signs requests in hashmap form. It returns a URL that should * be used to fetch the response. The URL returned should not be modified in * any way, doing so will invalidate the signature and Amazon will reject * the request. */ public String sign(Map<String, String> params) { // Let's add the AWSAccessKeyId and Timestamp parameters to the request. params.put("AWSAccessKeyId", this.awsAccessKeyId); params.put("Timestamp", this.timestamp()); params.put("AssociateTag", this.associateTag); // The parameters need to be processed in lexicographical order, so we'll // use a TreeMap implementation for that. SortedMap<String, String> sortedParamMap = new TreeMap<String, String>(params); // get the canonical form the query string String canonicalQS = this.canonicalize(sortedParamMap); // create the string upon which the signature is calculated String toSign = REQUEST_METHOD + "\n" + this.endpoint + "\n" + REQUEST_URI + "\n" + canonicalQS; // get the signature String hmac = this.hmac(toSign); String sig = this.percentEncodeRfc3986(hmac); // construct the URL String url = "http://" + this.endpoint + REQUEST_URI + "?" + canonicalQS + "&Signature=" + sig; return url; } /** * This method signs requests in query-string form. It returns a URL that * should be used to fetch the response. The URL returned should not be * modified in any way, doing so will invalidate the signature and Amazon * will reject the request. */ public String sign(String queryString) { // let's break the query string into it's constituent name-value pairs Map<String, String> params = this.createParameterMap(queryString); // then we can sign the request as before return this.sign(params); } /** * Compute the HMAC. * * @param stringToSign String to compute the HMAC over. * @return base64-encoded hmac value. */ private String hmac(String stringToSign) { String signature = null; byte[] data; byte[] rawHmac; try { data = stringToSign.getBytes(UTF8_CHARSET); rawHmac = mac.doFinal(data); Base64 encoder = new Base64(); signature = new String(encoder.encode(rawHmac)); } catch (UnsupportedEncodingException e) { throw new RuntimeException(UTF8_CHARSET + " is unsupported!", e); } return signature; } /** * Generate a ISO-8601 format timestamp as required by Amazon. * * @return ISO-8601 format timestamp. */ private String timestamp() { String timestamp = null; Calendar cal = Calendar.getInstance(); DateFormat dfm = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'"); dfm.setTimeZone(TimeZone.getTimeZone("GMT")); timestamp = dfm.format(cal.getTime()); return timestamp; } /** * Canonicalize the query string as required by Amazon. * * @param sortedParamMap Parameter name-value pairs in lexicographical order. * @return Canonical form of query string. */ private String canonicalize(SortedMap<String, String> sortedParamMap) { if (sortedParamMap.isEmpty()) { return ""; } StringBuffer buffer = new StringBuffer(); Iterator<Map.Entry<String, String>> iter = sortedParamMap.entrySet().iterator(); while (iter.hasNext()) { Map.Entry<String, String> kvpair = iter.next(); buffer.append(percentEncodeRfc3986(kvpair.getKey())); buffer.append("="); buffer.append(percentEncodeRfc3986(kvpair.getValue())); if (iter.hasNext()) { buffer.append("&"); } } String cannoical = buffer.toString(); return cannoical; } /** * Percent-encode values according the RFC 3986. The built-in Java * URLEncoder does not encode according to the RFC, so we make the * extra replacements. * * @param s decoded string * @return encoded string per RFC 3986 */ private String percentEncodeRfc3986(String s) { String out; try { out = URLEncoder.encode(s, UTF8_CHARSET) .replace("+", "%20") .replace("*", "%2A") .replace("%7E", "~"); } catch (UnsupportedEncodingException e) { out = s; } return out; } /** * Takes a query string, separates the constituent name-value pairs * and stores them in a hashmap. * * @param queryString * @return */ private Map<String, String> createParameterMap(String queryString) { Map<String, String> map = new HashMap<String, String>(); String[] pairs = queryString.split("&"); for (String pair: pairs) { if (pair.length() < 1) { continue; } String[] tokens = pair.split("=",2); for(int j=0; j<tokens.length; j++) { try { tokens[j] = URLDecoder.decode(tokens[j], UTF8_CHARSET); } catch (UnsupportedEncodingException e) { } } switch (tokens.length) { case 1: { if (pair.charAt(0) == '=') { map.put("", tokens[0]); } else { map.put(tokens[0], ""); } break; } case 2: { map.put(tokens[0], tokens[1]); break; } } } return map; } }
参照:Amazon Product Advertising API を利用して世界各国の商品価格差リサーチツールを作ってみる | imagination-i