Retrofit2.0 完美同步Cookie实现免登录

原文出自csdn：
http://blog.csdn.net/sk719887916/article/details/51700659；

通过对Retrofit2.0的<Retrofit 2.0 超能实践，完美支持Https传输>基础入门和案例实践，掌握了怎么样使用Retrofit访问网络，加入自定义header，包括加入SSL证书，基本的调试基础，但是正常的开发中会涉及cookie同步问题，可以实现一些自动或免登录登陆问题，接下来进入cookie同步姿势

Cookie

Cookies是一种能够让网站服务器把少量数据储存到客户端的硬盘或内存，或是从客户端的硬盘读取数据的一种技术。Cookies是当你浏览某网站时，由Web服务器置于你硬盘上的一个非常小的文本文件，它可以记录你的用户ID、密码、浏览过的网页、停留的时间等信息。当你再次来到该网站时，网站通过读取Cookies，得知你的相关信息，就可以做出相应的动作，如在页面显示欢迎你的标语，或者让你不用输入ID、密码就直接登录等等。

从本质上讲，它可以看作是你的身份证。但Cookies不能作为代码执行，也不会传送病毒，且为你所专有，并只能由提供它的服务器来读取。保存的信息片断以“名/值”对(name-value pairs)的形式储存，一个“名/值”对仅仅是一条命名的数据。一个网站只能取得它放在你的电脑中的信息，它无法从其它的Cookies文件中取得信息，也无法得到你的电脑上的其它任何东西。

Cookies中的内容大多数经过了加密处理，因此一般用户看来只是一些毫无意义的字母数字组合，只有服务器的CGI处理程序才知道它们真正的含义。

Cookie也是http的会话跟踪技术，也包含web端的session。cookie的作用就是为了解决HTTP协议无状态的缺陷所作的努力.

自定义cookie

HttpClient中大家都知道加入cookie的方式

AsyncHttpClient client = new AsyncHttpClient();
PersistentCookieStore myCookieStore = new PersistentCookieStore(MainActivity.this);
client.setCookieStore(myCookieStore);

因此Retrofit中需自我实现一个PersistentCookieStore 用来储存OkHttpCookies。

-PersistentCookieStore

/**
  * Created by LIUYONGKUI on 2016-06-09.
  */
public class PersistentCookieStore {
private static final String LOG_TAG = "PersistentCookieStore";
private static final String COOKIE_PREFS = "Cookies_Prefs";

private final Map<String, ConcurrentHashMap<String, Cookie>> cookies;
private final SharedPreferences cookiePrefs;


public PersistentCookieStore(Context context) {
    cookiePrefs = context.getSharedPreferences(COOKIE_PREFS, 0);
    cookies = new HashMap<>();

    //将持久化的cookies缓存到内存中 即map cookies
    Map<String, ?> prefsMap = cookiePrefs.getAll();
    for (Map.Entry<String, ?> entry : prefsMap.entrySet()) {
        String[] cookieNames = TextUtils.split((String) entry.getValue(), ",");
        for (String name : cookieNames) {
            String encodedCookie = cookiePrefs.getString(name, null);
            if (encodedCookie != null) {
                Cookie decodedCookie = decodeCookie(encodedCookie);
                if (decodedCookie != null) {
                    if (!cookies.containsKey(entry.getKey())) {
                        cookies.put(entry.getKey(), new ConcurrentHashMap<String, Cookie>());
                    }
                    cookies.get(entry.getKey()).put(name, decodedCookie);
                }
            }
        }
    }
}

protected String getCookieToken(Cookie cookie) {
    return cookie.name() + "@" + cookie.domain();
}

public void add(HttpUrl url, Cookie cookie) {
    String name = getCookieToken(cookie);

    //将cookies缓存到内存中 如果缓存过期 就重置此cookie
    if (!cookie.persistent()) {
        if (!cookies.containsKey(url.host())) {
            cookies.put(url.host(), new ConcurrentHashMap<String, Cookie>());
        }
        cookies.get(url.host()).put(name, cookie);
    } else {
        if (cookies.containsKey(url.host())) {
            cookies.get(url.host()).remove(name);
        }
    }

    //讲cookies持久化到本地
    SharedPreferences.Editor prefsWriter = cookiePrefs.edit();
    prefsWriter.putString(url.host(), TextUtils.join(",", cookies.get(url.host()).keySet()));
    prefsWriter.putString(name, encodeCookie(new OkHttpCookies(cookie)));
    prefsWriter.apply();
}

public List<Cookie> get(HttpUrl url) {
    ArrayList<Cookie> ret = new ArrayList<>();
    if (cookies.containsKey(url.host()))
        ret.addAll(cookies.get(url.host()).values());
    return ret;
}

public boolean removeAll() {
    SharedPreferences.Editor prefsWriter = cookiePrefs.edit();
    prefsWriter.clear();
    prefsWriter.apply();
    cookies.clear();
    return true;
}

public boolean remove(HttpUrl url, Cookie cookie) {
    String name = getCookieToken(cookie);

    if (cookies.containsKey(url.host()) && cookies.get(url.host()).containsKey(name)) {
        cookies.get(url.host()).remove(name);

        SharedPreferences.Editor prefsWriter = cookiePrefs.edit();
        if (cookiePrefs.contains(name)) {
            prefsWriter.remove(name);
        }
        prefsWriter.putString(url.host(), TextUtils.join(",", cookies.get(url.host()).keySet()));
        prefsWriter.apply();

        return true;
    } else {
        return false;
    }
}

public List<Cookie> getCookies() {
    ArrayList<Cookie> ret = new ArrayList<>();
    for (String key : cookies.keySet())
        ret.addAll(cookies.get(key).values());

    return ret;
}

/**
 * cookies 序列化成 string
 *
 * @param cookie 要序列化的cookie
 * @return 序列化之后的string
 */
protected String encodeCookie(OkHttpCookies cookie) {
    if (cookie == null)
        return null;
    ByteArrayOutputStream os = new ByteArrayOutputStream();
    try {
        ObjectOutputStream outputStream = new ObjectOutputStream(os);
        outputStream.writeObject(cookie);
    } catch (IOException e) {
        Log.d(LOG_TAG, "IOException in encodeCookie", e);
        return null;
    }

    return byteArrayToHexString(os.toByteArray());
}

/**
 * 将字符串反序列化成cookies
 *
 * @param cookieString cookies string
 * @return cookie object
 */
protected Cookie decodeCookie(String cookieString) {
    byte[] bytes = hexStringToByteArray(cookieString);
    ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(bytes);
    Cookie cookie = null;
    try {
        ObjectInputStream objectInputStream = new ObjectInputStream(byteArrayInputStream);
        cookie = ((OkHttpCookies) objectInputStream.readObject()).getCookies();
    } catch (IOException e) {
        Log.d(LOG_TAG, "IOException in decodeCookie", e);
    } catch (ClassNotFoundException e) {
        Log.d(LOG_TAG, "ClassNotFoundException in decodeCookie", e);
    }

    return cookie;
}

/**
 * 二进制数组转十六进制字符串
 *
 * @param bytes byte array to be converted
 * @return string containing hex values
 */
protected String byteArrayToHexString(byte[] bytes) {
    StringBuilder sb = new StringBuilder(bytes.length * 2);
    for (byte element : bytes) {
        int v = element & 0xff;
        if (v < 16) {
            sb.append('0');
        }
        sb.append(Integer.toHexString(v));
    }
    return sb.toString().toUpperCase(Locale.US);
}

/**
 * 十六进制字符串转二进制数组
 *
 * @param hexString string of hex-encoded values
 * @return decoded byte array
 */
protected byte[] hexStringToByteArray(String hexString) {
    int len = hexString.length();
    byte[] data = new byte[len / 2];
    for (int i = 0; i < len; i += 2) {
        data[i / 2] = (byte) ((Character.digit(hexString.charAt(i), 16) << 4) + Character.digit(hexString.charAt(i + 1), 16));
    }
    return data;
}

- OkHttpCookies

需要实现序列化的 OkHttpCookies 用来持久OkHttpCookies

   /**
 * Created by LIUYONGKUI on 2016-05-20.
  */
public class OkHttpCookies implements Serializable {

private transient final Cookie cookies;
private transient Cookie clientCookies;

public OkHttpCookies(Cookie cookies) {
    this.cookies = cookies;
}

public Cookie getCookies() {
    Cookie bestCookies = cookies;
    if (clientCookies != null) {
        bestCookies = clientCookies;
    }
    return bestCookies;
}

private void writeObject(ObjectOutputStream out) throws IOException {
    out.writeObject(cookies.name());
    out.writeObject(cookies.value());
    out.writeLong(cookies.expiresAt());
    out.writeObject(cookies.domain());
    out.writeObject(cookies.path());
    out.writeBoolean(cookies.secure());
    out.writeBoolean(cookies.httpOnly());
    out.writeBoolean(cookies.hostOnly());
    out.writeBoolean(cookies.persistent());
}

private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
    String name = (String) in.readObject();
    String value = (String) in.readObject();
    long expiresAt = in.readLong();
    String domain = (String) in.readObject();
    String path = (String) in.readObject();
    boolean secure = in.readBoolean();
    boolean httpOnly = in.readBoolean();
    boolean hostOnly = in.readBoolean();
    boolean persistent = in.readBoolean();
    Cookie.Builder builder = new Cookie.Builder();
    builder = builder.name(name);
    builder = builder.value(value);
    builder = builder.expiresAt(expiresAt);
    builder = hostOnly ? builder.hostOnlyDomain(domain) : builder.domain(domain);
    builder = builder.path(path);
    builder = secure ? builder.secure() : builder;
    builder = httpOnly ? builder.httpOnly() : builder;
    clientCookies =builder.build();
}

}

-自定义CookieManger

实现有一个自定义的CookieManger来管理cookies,实现以K-V结构获取set,getCookier

    public class CookieManger implements CookieJar {


public static String APP_PLATFORM = "app-platform";


private static Context mContext;

private static PersistentCookieStore cookieStore;

public CookieManger(Context context) {
    mContext = context;
    if (cookieStore == null ) {
        cookieStore = new PersistentCookieStore(mContext);
    }

}





@Override
public void saveFromResponse(HttpUrl url, List<Cookie> cookies) {
    if (cookies != null && cookies.size() > 0) {
        for (Cookie item : cookies) {
            cookieStore.add(url, item);
        }
    }
}

@Override
public List<Cookie> loadForRequest(HttpUrl url) {
    List<Cookie> cookies =cookieStore.get(url);
    return cookies;
}

static class Customer {

    private String userID;
    private String token;

    public Customer(String userID, String token) {
        this.userID = userID;
        this.token = token;
    }

    public String getUserID() {
        return userID;
    }

    public void setUserID(String userID) {
        this.userID = userID;
    }

    public String getToken() {
        return token;
    }

    public void setToken(String token) {
        this.token = token;
    }

}

- Retrofit加入cookie

OkHttpClient okHttpClient = new OkHttpClient.Builder()
            .addNetworkInterceptor(
                    new HttpLoggingInterceptor().setLevel(HttpLoggingInterceptor.Level.HEADERS))
            .cookieJar(new CookieManger(context))
            .addInterceptor(loginInterceptor)
            .connectTimeout(DEFAULT_TIMEOUT, TimeUnit.SECONDS)
            .build();


    Retrofit retrofit = new Retrofit.Builder()
            .client(okHttpClient)
            .build();

总结

实现加入cookies持久，实现免登陆基本步骤

1 实现可序列化的OkHttpcookies
2 实现储存OkHttpcookies的PersistentCookieStore
3 实现cookies管理工具CookieManger
4 构建OKHttpClient
5 Retrofit加入自定义的okHttpClient
6直接调用RetrofitClient

so iz 或许下一步你将会Retrofit遇到文件和图片上传问题，别急会 干货即将来临！

Retrofit入门:
Retrofit 2.0 超能实践，完美支持Https传输