一、 这篇文章要解决什么问题,能学习到什么?
最近要做一个院务系统的项目,会把我的学习新知识的过程记录下来,本篇文章是实现登录的操作,本来以为登录的过程是一件比较简单的事情,但是深入了解过后还是有一定难度:
- 1 在登录过程中要获取验证码照片,利用http的get操作后,要穿参数过去服务器,就要用post。
- 2 上述的get和post操作用很多现在网络的框架都能实现,比如volley,但是在获取验证码照片后是要进行一个session的保持的,所以在查阅资料后利用okhttp框架来构建这个项目比较方便快捷。
先来了解一下怎么使用okhttp:http://blog.csdn.net/itachi85/article/details/51190687
还有快速入门利用okhttp加载照片:
http://blog.csdn.net/bo543937071/article/details/53380651
二、问:什么是session和cookie?
简单来说,cookie就是客户端的会话id,而session就是服务器端的会话id,根据这个id号可以查询到你的会话内容。
(想要了解更多cookie和session的知识可以点击这里)
在本项目中用到的是验证码照片的获取,因为每次刷新验证码的url都会有不同的验证码照片出现,所以需要保存验证码的session,不然别人怎么知道你和哪个验证码进行了“会话”。先上照片:
如图分为四个步骤,结合文字更容易理解:
- 1客户端发个请求验证码照片的请求,带回来了照片和一个jsessionid的字段存在用户的cookie中。
- 2我们从cookie头中取出这个session,然后打包参数发过去的时候顺便带上这个session,让服务器这个家伙知道是谁发的。
四个步骤两点总结,在加上代码就更好理解了。
三、分析部分重要代码 最后再贴上全部代码
看一下后台那边给我们的数据有什么,有url_randCodeImage用来发送get请求获取照片,还有url_login用来post数据过去,这些就是我们要打包发送过去的数据:
还有我们的xml界面
首先是我们的验证码照片的获取与异步加载图片
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//发送请求获取验证码照片 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(); //通过handler更新UI Message message = handler.obtainMessage(); message.obj = byte_image; message.what = SUCCESS; Log.i("info_handler","handler"); handler.sendMessage(message); //获取session的操作,session放在cookie头,且取出后含有“;”,取出后为下面的 s (也就是jsesseionid) Headers headers = response.headers(); Log.d("info_headers", "header " + headers); List<String> 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); } }); } //异步加载图片 public Handler handler = new Handler(){ @Override public void handleMessage(Message msg) { switch (msg.what){ //加载网络成功进行UI的更新,处理得到的图片资源 case SUCCESS: //通过message,拿到字节数组 byte[] Picture = (byte[]) msg.obj; //使用BitmapFactory工厂,把字节数组转化为bitmap Bitmap bitmap = BitmapFactory.decodeByteArray(Picture, 0, Picture.length); //通过imageview,设置图片 img_identy.setImageBitmap(bitmap); break; //当加载网络失败执行的逻辑代码 case FALL: Toast.makeText(MainActivity.this, "网络出现了问题", Toast.LENGTH_SHORT).show(); break; } } }; |
获取了照片和session之后,我们就打包发送数据过去:
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private void LoginServer() { Log.i("info_Login","知道了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+""); } }); } |
最后来看看我们成功登录后log出来的信息
最后贴上我们的全部代码,希望对过程不太理解的小伙伴有所帮助:
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public class MainActivity extends Activity { private EditText et_username,et_code,et_identy; private Button btn_login,btn_changeImg; private ImageView img_identy; private Context context; private OkHttpClient okHttpClient; public String s ; private static final int SUCCESS = 1; private static final int FALL = 2; public Handler handler = new Handler(){ @Override public void handleMessage(Message msg) { switch (msg.what){ //加载网络成功进行UI的更新,处理得到的图片资源 case SUCCESS: //通过message,拿到字节数组 byte[] Picture = (byte[]) msg.obj; //使用BitmapFactory工厂,把字节数组转化为bitmap Bitmap bitmap = BitmapFactory.decodeByteArray(Picture, 0, Picture.length); //通过imageview,设置图片 img_identy.setImageBitmap(bitmap); break; //当加载网络失败执行的逻辑代码 case FALL: Toast.makeText(MainActivity.this, "网络出现了问题", Toast.LENGTH_SHORT).show(); break; } } }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); init(); context = getApplicationContext(); ChangeImage(); btn_changeImg.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { ChangeImage(); } }); btn_login.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { LoginServer(); } }); } private void LoginServer() { Log.i("info_Login","知道了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+""); } }); } 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(); //通过handler更新UI Message message = handler.obtainMessage(); message.obj = byte_image; message.what = SUCCESS; Log.i("info_handler","handler"); handler.sendMessage(message); //session Headers headers = response.headers(); Log.d("info_headers", "header " + headers); List<String> 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); } }); } private void init() { et_username = (EditText) findViewById(R.id.et_username); et_code = (EditText) findViewById(R.id.et_code); et_identy = (EditText) findViewById(R.id.et_identy); btn_login = (Button) findViewById(R.id.btn_login); img_identy = (ImageView) findViewById(R.id.img_identy); btn_changeImg = (Button) findViewById(R.id.btn_changeImg); okHttpClient = new OkHttpClient(); } } |
来,头伸过来,给你们几个宝贝看看(我在学习过程中参考查阅的文章的):
http://blog.csdn.net/itachi85/article/details/51190687
http://blog.csdn.net/bo543937071/article/details/53380651
http://blog.csdn.net/androidxiaogang/article/details/51943216
最新评论
嗯,很不错,看了的确很受用,谢谢楼主
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使用基于okhttp的okGo会不会更方便呢?
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很不错,正好有用,谢谢
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谢谢,非常有用。
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