Shulou(Shulou.com)06/02 Report--

Editor to share with you how to use the okhttp framework to achieve the user login including CAPTCHA and maintain the session operation, I believe that most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to know it!

First, what problems can be solved and what can be learned from this article?

Recently, I will work on a hospital administration system project, which will record my process of learning new knowledge. this article is to realize the login operation. I originally thought that the login process was a relatively simple thing, but there is still some difficulty after in-depth understanding:

1. In the login process to get the CAPTCHA photo, after using the get operation of http, to pass the parameters to the server, you need to use post.

two。 The above get and post operations can be implemented in many current network frameworks, such as volley, but it is necessary to maintain a session after obtaining the CAPTCHA photo, so it is more convenient and quick to use the okhttp framework to build this project after consulting the data.

Q: what are session and cookie?

To put it simply, cookie is the session id on the client side, and session is the session id on the server side. Your session content can be queried according to this id number.

(to learn more about cookie and session, please click here.)

Http://blog.csdn.net/androidxiaogang/article/details/51925388

What is used in this project is the acquisition of CAPTCHA photos, because the url of each refresh CAPTCHA will have a different CAPTCHA photo, so you need to save the CAPTCHA session, otherwise how will others know which CAPTCHA you have a "conversation" with. Take the photo first:

As shown in the figure, there are four steps, which are easier to understand when combined with the text:

1. The client sends a request for a CAPTCHA photo, bringing back the photo and a jsessionid field to be stored in the user's cookie.

two。 Let's take the session out of the cookie header and bring the session along when we send the package parameters to let the server guy know who sent it.

Summarize the four steps and two points, and add the code to make it easier to understand.

Analyze some important codes * * and paste all the codes

Let's take a look at the data given to us at the backend. Url_randCodeImage is used to send get requests to get photos, and url_login is used to post data in the past. These are the data we need to package and send:

And our xml interface.

The first is the acquisition of our CAPTCHA photos and the asynchronous loading of images.

/ / send a request to get the verification code photo private void ChangeImage () {Request request = new Request.Builder () .url (App.url_randCodeImage) .build (); Call call = okHttpClient.newCall (request) Call.enqueue (new Callback () {@ Override public void onFailure (Call call, IOException e) {Log.i ("info_callFailure", e.toString ());} @ Override public void onResponse (Call call, Response response) throws IOException {byte [] byte_image = response.body () .bytes () / / Update UI Message message = handler.obtainMessage () via handler; message.obj = byte_image; message.what = SUCCESS; Log.i ("info_handler", "handler"); handler.sendMessage (message) / / the operation of getting session. The session is placed in the cookie header and contains " ", take out the following s (i.e. jsesseionid) Headers headers = response.headers (); Log.d (" info_headers "," header "+ headers); List cookies = headers.values (" Set-Cookie "); String session = cookies.get (0); Log.d (" info_cookies "," onResponse-size: "+ cookies) S = session.substring (0, session.indexOf (";"); Log.i ("info_s", "session is:" + s);}}) } / / asynchronously load pictures public Handler handler = new Handler () {@ Override public void handleMessage (Message msg) {switch (msg.what) {/ / load the network successfully to update the UI, and get the image resources case SUCCESS: / / through message Get the byte array byte [] Picture = (byte []) msg.obj / / use the BitmapFactory factory to convert the byte array to bitmap Bitmap bitmap = BitmapFactory.decodeByteArray (Picture, 0, Picture.length); / / set the picture img_identy.setImageBitmap (bitmap) through imageview; break / / the logic code case FALL: Toast.makeText (MainActivity.this, "network problems", Toast.LENGTH_SHORT) executed when loading the network failed. Show (); break;}

After getting the photos and session, we package and send the data:

Private void LoginServer () {Log.i ("info_Login", "know session:" + s); OkHttpClient client = new OkHttpClient () FormBody body = new FormBody.Builder () .add ("userName", et_username.getText (). ToString ()) .add ("password", et_code.getText (). ToString ()) .add ("randCode", et_identy.getText (). ToString ()) .add ("langCode") "zh-cn") .build () Request request = new Request.Builder () .addHeader ("cookie", s) .url (App.url_login) .post (body) .build (); Call call2 = okHttpClient.newCall (request) Call2.enqueue (new Callback () {@ Override public void onFailure (Call call, IOException e) {Log.i ("info_call2fail", e.toString ()) } @ Override public void onResponse (Call call, Response response) throws IOException {if (response.isSuccessful ()) {Log.i ("info_call2success", response.body (). String ());} Headers headers = response.headers () Log.i ("info_respons.headers", headers+ ");}});}

* take a look at the information from log after we have successfully logged in.

The above is all the contents of the article "how to use the okhttp framework to achieve user login with CAPTCHA and maintain session operation". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.