本文和大家一起了解了一下android客戶端與服務端是怎樣交互的，具體內容如下
1.后臺使用簡單的servlet，支持GET或POST。這個servlet最終返回給前臺一個字符串flag，值是true或false，表示登錄是否成功。
servlet使用之前需要配置，主義servlet的servlet-name要和servlet-mapping的servlet-name一致，否則找不到路徑
我是在myEclipse上創建的一個web service 項目，然后部署到tomcat服務器上以便android客戶端訪問
<servlet> <servlet-name>helloWorld</servlet-name> <servlet-class>com.zhongzhong.wap.action.HelloServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>helloWorld</servlet-name> <url-pattern>/queryOrder</url-pattern> </servlet-mapping> 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;import javax.servlet.http.HttpSession; import com.zhongzhong.wap.bean.UserBean; public class HelloServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doPost(req, resp); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { resp.setContentType(text/html); PrintWriter out = resp.getWriter(); Boolean flag = false; String userName = req.getParameter(un); String password = req.getParameter(pw); if(userName.equals(htp)&&password.equals(123)) { flag = true; } else flag = false; System.out.println(userName:+userName+ password:+password); out.print(flag); out.flush(); out.close(); } }2.然后我是在安卓的ADT上創建一個安卓項目，建立兩個Activity，分別作為登錄界面和登錄成功界面。
<relativelayout android:layout_height="match_parent" android:layout_width="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" xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools"> <textview android:id="@+id/textView1" android:layout_alignparenttop="true" android:layout_centerhorizontal="true" android:layout_height="wrap_content" android:layout_margintop="40dp" android:layout_width="wrap_content" android:text="HelloWorld登陸示例"> <edittext android:ems="10" android:hint="請輸入賬號" android:id="@+id/et_user" android:layout_below="@+id/textView1" android:layout_centerhorizontal="true" android:layout_height="wrap_content" android:layout_margintop="33dp" android:layout_width="wrap_content"> <requestfocus> </requestfocus></edittext> <edittext android:ems="10" android:hint="請輸入密碼" android:id="@+id/et_psw" android:inputtype="textPassword" android:layout_below="@+id/et_user" android:layout_centerhorizontal="true" android:layout_height="wrap_content" android:layout_margintop="40dp" android:layout_width="wrap_content"><button android:id="@+id/btn_login" android:layout_below="@+id/et_psw" android:layout_centerhorizontal="true" android:layout_height="wrap_content" android:layout_margintop="37dp" android:layout_width="wrap_content" android:text="登陸"></button></edittext></textview></relativelayout> <relativelayout android:layout_height="match_parent" android:layout_width="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=".NaviActivity" xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools"> <textview android:layout_alignparenttop="true" android:layout_centerhorizontal="true" android:layout_height="wrap_content" android:layout_margintop="46dp" android:layout_width="wrap_content" android:text="登陸成功"> </textview></relativelayout>
3.HTTP的訪問公共類，用于處理GET和POST請求。
package com.example.logindemo; import java.util.ArrayList;import java.util.List;import java.util.Map; import org.apache.http.HttpResponse;import org.apache.http.NameValuePair;import org.apache.http.client.HttpClient;import org.apache.http.client.entity.UrlEncodedFormEntity;import org.apache.http.client.methods.HttpGet;import org.apache.http.client.methods.HttpPost;import org.apache.http.impl.client.DefaultHttpClient;import org.apache.http.message.BasicNameValuePair;import org.apache.http.util.EntityUtils; import android.content.Entity;import android.util.Log; public class HttpUtil { // 創建HttpClient對象 public static HttpClient httpClient = new DefaultHttpClient(); public static final String BASE_URL = http://192.168.3.14:8090/HelloWord/; /** * * @param url * 發送請求的URL * @return 服務器響應字符串 * @throws Exception */ public static String getRequest(String url) throws Exception { // 創建HttpGet對象。 HttpGet get = new HttpGet(url); // 發送GET請求 HttpResponse httpResponse = httpClient.execute(get); // 如果服務器成功地返回響應 if (httpResponse.getStatusLine().getStatusCode() == 200) { // 獲取服務器響應字符串 String result = EntityUtils.toString(httpResponse.getEntity()); return result; } else { Log.d(服務器響應代碼, (new Integer(httpResponse.getStatusLine() .getStatusCode())).toString()); return null; } } /** * * @param url * 發送請求的URL * @param params * 請求參數 * @return 服務器響應字符串 * @throws Exception */ public static String postRequest(String url, Map<string, string=""> rawParams) throws Exception { // 創建HttpPost對象。 HttpPost post = new HttpPost(url); // 如果傳遞參數個數比較多的話可以對傳遞的參數進行封裝 List<namevaluepair> params = new ArrayList<namevaluepair>(); for (String key : rawParams.keySet()) { // 封裝請求參數 params.add(new BasicNameValuePair(key, rawParams.get(key))); } // 設置請求參數 post.setEntity(new UrlEncodedFormEntity(params, UTF-8)); // 發送POST請求 HttpResponse httpResponse = httpClient.execute(post); // 如果服務器成功地返回響應 if (httpResponse.getStatusLine().getStatusCode() == 200) { // 獲取服務器響應字符串 String result = EntityUtils.toString(httpResponse.getEntity()); return result; } return null; }}</namevaluepair></namevaluepair></string,>4.IntentService服務，用于在后臺以隊列方式處理耗時操作。
package com.example.logindemo; import java.util.HashMap; import android.app.IntentService;import android.content.Intent;import android.util.Log; public class ConnectService extends IntentService { private static final String ACTION_RECV_MSG = com.example.logindemo.action.RECEIVE_MESSAGE; public ConnectService() { super(TestIntentService); // TODO Auto-generated constructor stub } @Override protected void onHandleIntent(Intent intent) { // TODO Auto-generated method stub /** * 經測試，IntentService里面是可以進行耗時的操作的 * IntentService使用隊列的方式將請求的Intent加入隊列， * 然后開啟一個worker thread(線程)來處理隊列中的Intent * 對于異步的startService請求，IntentService會處理完成一個之后再處理第二個 */ Boolean flag = false; //通過intent獲取主線程傳來的用戶名和密碼字符串 String username = intent.getStringExtra(username); String password = intent.getStringExtra(password); flag = doLogin(username, password); Log.d(登錄結果, flag.toString()); Intent broadcastIntent = new Intent(); broadcastIntent.setAction(ACTION_RECV_MSG); broadcastIntent.addCategory(Intent.CATEGORY_DEFAULT); broadcastIntent.putExtra(result, flag.toString()); sendBroadcast(broadcastIntent); } // 定義發送請求的方法 private Boolean doLogin(String username, String password) { String strFlag = ; // 使用Map封裝請求參數 HashMap<string, string=""> map = new HashMap<string, string="">(); map.put(un, username); map.put(pw, password); // 定義發送請求的URL String url = HttpUtil.BASE_URL + queryOrder?un= + username + &pw= + password; //GET方式 // String url = HttpUtil.BASE_URL + LoginServlet; //POST方式 Log.d(url, url); Log.d(username, username); Log.d(password, password); try { // 發送請求 strFlag = HttpUtil.postRequest(url, map); //POST方式 // strFlag = HttpUtil.getRequest(url); //GET方式 Log.d(服務器返回值, strFlag); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } if(strFlag.trim().equals(true)){ return true; }else{ return false; } } }</string,></string,>5.在AndroidManifest.xml中注冊IntentService。注意uses-permission節點，為程序開啟訪問網絡的權限。
<!--?xml version=1.0 encoding=utf-8?--><manifest android:versioncode="1" android:versionname="1.0" package="com.example.logindemo" xmlns:android="http://schemas.android.com/apk/res/android"> <uses-sdk android:minsdkversion="8" android:targetsdkversion="18"> <uses-permission android:name="android.permission.INTERNET"> <intent-filter> <category android:name="android.intent.category.LAUNCHER"> </category></action></intent-filter> </activity> </activity> <service android:name="com.example.logindemo.ConnectService"> </service> </application> </uses-permission></uses-sdk></manifest>
6.登陸界面處理，注意
按鈕監聽事件中，使用Intent將要傳遞的值傳給service。接收廣播類中，同樣使用Intent將要傳遞的值傳給下一個Activity。在onCreate()中，動態注冊接收廣播類的實例receiver。在接收廣播類中，不要使用完畢后忘記注銷接收器，否則會報一個Are you missing a call to unregisterReceiver()? 的異常。
package com.example.logindemo; import android.os.Bundle;import android.app.Activity;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;import android.content.IntentFilter;import android.util.Log;import android.view.Menu;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.Toast; public class MainActivity extends Activity { private static final String ACTION_RECV_MSG = com.example.logindemo.action.RECEIVE_MESSAGE; private Button loginBtn; private EditText et_username; private EditText et_password; private String userName; private String passWord; private MessageReceiver receiver ; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initView(); //動態注冊receiver IntentFilter filter = new IntentFilter(ACTION_RECV_MSG); filter.addCategory(Intent.CATEGORY_DEFAULT); receiver = new MessageReceiver(); registerReceiver(receiver, filter); } private void initView() { // TODO Auto-generated method stub et_username = (EditText)findViewById(R.id.et_user); et_password =( EditText)findViewById(R.id.et_psw); loginBtn = (Button)findViewById(R.id.btn_login); loginBtn.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub if(matchLoginMsg()) { // 如果校驗成功 Intent msgIntent = new Intent(MainActivity.this, ConnectService.class); msgIntent.putExtra(username, et_username.getText().toString().trim()); msgIntent.putExtra(password, et_password.getText().toString().trim()); startService(msgIntent); } } }); } protected boolean matchLoginMsg() { // TODO Auto-generated method stub userName = et_username.getText().toString().trim(); passWord = et_password.getText().toString().trim(); if(userName.equals()) { Toast.makeText(MainActivity.this, 賬號不能為空,Toast.LENGTH_SHORT).show(); return false; } if(passWord.equals()) { Toast.makeText(MainActivity.this, 密碼不能為空,Toast.LENGTH_SHORT).show(); return false; } return true; } //接收廣播類 public class MessageReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { String message = intent.getStringExtra(result); Log.i(MessageReceiver, message); // 如果登錄成功 if (message.equals(true)){ // 啟動Main Activity Intent nextIntent = new Intent(MainActivity.this, NaviActivity.class); startActivity(nextIntent); // 結束該Activity finish(); //注銷廣播接收器 context.unregisterReceiver(this); }else{ Toast.makeText(MainActivity.this, 用戶名或密碼錯誤，請重新輸入!,Toast.LENGTH_SHORT).show(); } } } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } }以上就是本文的全部內容，希望對大家的學習有所幫助。
新聞熱點
疑難解答
圖片精選
