The second method of data interaction between the Android client and the server is android server.

The second method of data interaction between the Android client and the server is android server.

There are many examples on the Internet to demonstrate how the Android client interacts with the server. However, these examples are mostly complicated, which is not good for beginners, here are some examples of simple code and clear logic interaction. This blog introduces the second one:

I. server side:

Code 1: Add a file named "AndroidServerServlet. java"

Package com. ghj. packageofservlet; import java. io. IOException; import java. io. printWriter; import javax. servlet. servletException; import javax. servlet. http. httpServlet; import javax. servlet. http. httpServletRequest; import javax. servlet. http. httpServletResponse; public class AndroidServerServlet extends HttpServlet {private static final long serialVersionUID = 6792316567928634227l; public void doPost (HttpSer VletRequest request, HttpServletResponse response) throws ServletException, IOException {response. setContentType ("text/plain; charsets = UTF-8"); request. setCharacterEncoding ("UTF-8"); System. err. println (request. getParameter ("clientData"); PrintWriter printWriter = response. getWriter (); printWriter. print ("Hello Android client! "); PrintWriter. flush (); printWriter. close ();}}

Code 2: modify a file named "web. xml"

<?xml version="1.0" encoding="UTF-8"?><web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"><servlet><servlet-name>AndroidServerServlet</servlet-name><servlet-class>com.ghj.packageofservlet.AndroidServerServlet</servlet-class></servlet><servlet-mapping><servlet-name>AndroidServerServlet</servlet-name><url-pattern>/AndroidServerServlet</url-pattern></servlet-mapping></web-app>

Ii. Android mobile client:

Code 1: Add a file named "AndroidClientActivity. java"

Package com. example. androidclient; import java. io. IOException; import java. io. unsupportedEncodingException; import java. util. arrayList; import java. util. list; import org. apache. http. httpResponse; import org. apache. http. nameValuePair; import org. apache. http. client. clientProtocolException; import org. apache. http. client. httpClient; import org. apache. http. client. entity. urlEncodedFormEntity; import org. apache. htt P. client. methods. httpPost; import org. apache. http. impl. client. defaultHttpClient; import org. apache. http. message. basicNameValuePair; import org. apache. http. protocol. HTTP; import org. apache. http. util. entityUtils; import android. app. activity; import android. OS. bundle; import android. OS. handler; import android. OS. message; import android. view. view; import android. view. view. onClickListener; import android. widget. B Utton; import android. widget. toast; public class AndroidClientActivity extends Activity {@ Overrideprotected void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (R. layout. android_client); Button sendButton = (Button) findViewById (R. id. send_button); sendButton. setOnClickListener (new OnClickListener () {@ Overridepublic void onClick (View v) {new Thread (new Runnable (){ @ Override public void run () {HttpPost httpRequest = new HttpPost ("http: // 172.16.99.207: 8080/AndroidServer/AndroidServerServlet "); list <NameValuePair> params = new ArrayList <NameValuePair> (); params. add (new BasicNameValuePair ("clientData", "Hello, server! "); Try {Message message = new Message (); Bundle bundle = new Bundle (); httpRequest. setEntity (new UrlEncodedFormEntity (params, HTTP. UTF_8); // sets the request parameter item HttpClient httpClient = new DefaultHttpClient (); HttpResponse httpResponse = httpClient.exe cute (httpRequest); // executes the request to return a response if (httpResponse. getStatusLine (). getStatusCode () = 200) {// determine whether the bundle request is successful. putString ("msg", EntityUtils. toString (httpResponse. getE Ntity ();} else {bundle. putString ("msg", "no response from the Android server is obtained! ");} Message. setData (bundle); handler. sendMessage (message);} catch (ClientProtocolException e) {e. printStackTrace ();} catch (UnsupportedEncodingException e) {e. printStackTrace ();} catch (IOException e) {e. printStackTrace ();}}}). start () ;}}) ;}private Handler handler = new Handler () {@ Overridepublic void handleMessage (Message message) {super. handleMessage (message); Bundle bundle = message. getData (); String msg = bundle. getString ("msg"); Toast. makeText (getApplicationContext (), msg, Toast. LENGTH_LONG ). show ();}};}

Code 2: Add a file named "android_client.xml"

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context=".MainActivity" >   <Button       android:id="@+id/send_button"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_centerHorizontal="true"       android:layout_centerVertical="true"       android:text="@string/hello_server" /></RelativeLayout>

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