1.ClientLogin
2.AuthSub
3.OAuth
この中でClientLoginをやってみました(OAuthがGAEなどで主流ですが、訳ありです)。
(i) GData ライブラリの追加
https://code.google.com/p/gdata-java-client/downloads/list
gdata-samples.java-1.47.1.zipをダウンロードして展開します。
(ii)Eclipseでプロジェクト作成
例えば
プロジェクト名：Prog_google
パッケージ：なし（つけてもOK)
クラス名：ClientLogin
ビルドパスから外部Jarファイルの追加で先ほど展開したgdata->java->lib の必要なものをインポートします（必要なものがわからなければ全部インポートしてください）
(iii)クラスの作成
以下のコードをクラスに書きます
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.*;
import java.util.StringTokenizer;
public class ClientLogin {
/**
* URL used for authenticating and obtaining an authentication token.
* More details about how it works:
*
http://code.google.com/apis/accounts/AuthForInstalledApps.html
*/
private static final String AUTHENTICATION_URL = "https://www.google.com/accounts/ClientLogin";
private String EMAIL ;
private String PASSWORD;
private String SERVICE;
public static void main(String[] args) {
ClientLogin cl = new ClientLogin(args[0], args[1], args[2]) ;
System.out.println(cl.authenticate());
}
public ClientLogin(String email, String password, String service){
this.EMAIL = email;
this.PASSWORD = password;
this.SERVICE = service;
}
/**
* Retrieves the authentication token for the provided set of credentials.
* @return the authorization token that can be used to access authenticated
* Google Base data API feeds
*/
public String authenticate() {
// create the login request
String postOutput = null;
try {
URL url = new URL(AUTHENTICATION_URL);
postOutput = makeLoginRequest(url);
} catch (IOException e) {
System.out.println("Could not connect to authentication server: "
+ e.toString());
System.exit(1);
}
// Parse the result of the login request. If everything went fine, the
// response will look like
// HTTP/1.0 200 OK
// Server: GFE/1.3
// Content-Type: text/plain
// SID=DQAAAGgA...7Zg8CTN
// LSID=DQAAAGsA...lk8BBbG
// Auth=DQAAAGgA...dk3fA5N
// so all we need to do is look for "Auth" and get the token that comes after it
StringTokenizer tokenizer = new StringTokenizer(postOutput, "=\n ");
String token = null;
while (tokenizer.hasMoreElements()) {
if (tokenizer.nextToken().equals("Auth")) {
if (tokenizer.hasMoreElements()) {
token = tokenizer.nextToken();
}
break;
}
}
if (token == null) {
System.out.println("Authentication error. Response from server:\n" + postOutput);
System.exit(1);
}
return token;
}
/**
* Makes a HTTP POST request to the provided {@code url} given the provided
* {@code parameters}. It returns the output from the POST handler as a
* String object.
*
* @param url the URL to post the request
* @return the output from the Google Accounts server, as string
* @throws IOException if an I/O exception occurs while
* creating/writing/reading the request
*/
private String makeLoginRequest(URL url)
throws IOException {
// Create a login request. A login request is a POST request that looks like
// POST /accounts/ClientLogin HTTP/1.0
// Content-type: application/x-www-form-urlencoded
// Email=johndoe@gmail.com&Passwd=north23AZ&service=gbase&source=Insert Example
// Open connection
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
// Set properties of the connection
urlConnection.setRequestMethod("POST");
urlConnection.setDoInput(true);
urlConnection.setDoOutput(true);
urlConnection.setUseCaches(false);
urlConnection.setRequestProperty("Content-Type",
"application/x-www-form-urlencoded");
// Form the POST parameters
StringBuilder content = new StringBuilder();
content.append("Email=").append(URLEncoder.encode(EMAIL, "UTF-8"));
content.append("&Passwd=").append(URLEncoder.encode(PASSWORD, "UTF-8"));
content.append("&service=").append(URLEncoder.encode(SERVICE, "UTF-8"));
content.append("&source=").append(URLEncoder.encode("Google Base data API", "UTF-8"));
OutputStream outputStream = urlConnection.getOutputStream();
outputStream.write(content.toString().getBytes("UTF-8"));
outputStream.close();
// Retrieve the output
int responseCode = urlConnection.getResponseCode();
InputStream inputStream;
if (responseCode == HttpURLConnection.HTTP_OK) {
inputStream = urlConnection.getInputStream();
} else {
inputStream = urlConnection.getErrorStream();
}
return toString(inputStream);
}
/**
* Writes the content of the input stream to a
String.*/
private String toString(InputStream inputStream) throws IOException {
String string;
StringBuilder outputBuilder = new StringBuilder();
if (inputStream != null) {
BufferedReader reader =
new BufferedReader(new InputStreamReader(inputStream));
while (null != (string = reader.readLine())) {
outputBuilder.append(string).append('\n');
}
}
return outputBuilder.toString();
}
}
もとはここからhttp://gcs-admin-toolkit.googlecode.com/svn/trunk/src/apiinsert/ClientLogin.java
(iv)実行
これを実行するには３つの引数が必要です。
this.EMAIL = email;
this.PASSWORD = password;
this.SERVICE = service;
これがmain関数の引数になっています。
Eclipseでmain関数の引数を指定するには、実行->実行構成->引数を指定します。
第１引数がメールアドレス、
第２引数がパスワード
第３引数がサービス名です。
サービス名は図のようになっています。
これで実行して認証がうまくいけば、トークンが返ってきます。
ダメな場合はエラーが表示されます。
この認証後、トークンを使ってサービスを利用できます。
