Android 客户端与服务端交互之登陆示例（Android+servlet+JavaBean+tomcat）

今天了解了一下 android 客户端与服务端是怎样交互的，发现其实跟 web 有点类似吧，然后网上找了大神的登陆示例，是基于 IntentService 的

1. 后台使用简单的 servlet，支持 GET 或 POST。这个 servlet 最终返回给前台一个字符串 flag，值是 true 或 false，表示登录是否成功。

servlet 使用之前需要配置，主义 servlet 的 servlet-name 要和 servlet-mapping 的 servlet-name 一致，否则找不到路径

我是在 myEclipse 上创建的一个 web service 项目，然后部署到 tomcat 服务器上以便 android 客户端访问

1 2 3 4 5 6 7 8 helloWorld class >com.zhongzhong.wap.action.HelloServlet class > helloWorld /queryOrder

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 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 上创建一个安卓项目，建立两个 Activity，分别作为登录界面和登录成功界面。

1 2 3 4 5 6 7 8 9 10 "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= "https://schemas.android.com/apk/res/android" xmlns:tools= "https://schemas.android.com/tools" > "@+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登陆示例" > "10" android:hint= "请输入账号" 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" > "10" android:hint= "请输入密码" 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" >

1 2 3 4 5 "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= "https://schemas.android.com/apk/res/android" xmlns:tools= "https://schemas.android.com/tools" > "true" android:layout_centerhorizontal= "true" android:layout_height= "wrap_content" android:layout_margintop= "46dp" android:layout_width= "wrap_content" android:text= "登陆成功" >

3.HTTP 的访问公共类，用于处理 GET 和 POST 请求

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 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 { // 创建HttpClient对象 public static HttpClient httpClient = new DefaultHttpClient(); public static final String BASE_URL = https: //192.168.3.14:8090/HelloWord/; /** * * @param url * 发送请求的URL * @return 服务器响应字符串 * @throws Exception */ public static String getRequest(String url) throws Exception { // 创建HttpGet对象。 HttpGet get = new HttpGet(url); // 发送GET请求 HttpResponse httpResponse = httpClient.execute(get); // 如果服务器成功地返回响应 if (httpResponse.getStatusLine().getStatusCode() == 200 ) { // 获取服务器响应字符串 String result = EntityUtils.toString(httpResponse.getEntity()); return result; } else { Log.d(服务器响应代码, ( new Integer(httpResponse.getStatusLine() .getStatusCode())).toString()); return null ; } } /** * * @param url * 发送请求的URL * @param params * 请求参数 * @return 服务器响应字符串 * @throws Exception */ public static String postRequest(String url, Map "" > rawParams) throws Exception { // 创建HttpPost对象。 HttpPost post = new HttpPost(url); // 如果传递参数个数比较多的话可以对传递的参数进行封装 List params = new ArrayList(); for (String key : rawParams.keySet()) { // 封装请求参数 params.add( new BasicNameValuePair(key, rawParams.get(key))); } // 设置请求参数 post.setEntity( new UrlEncodedFormEntity(params, UTF- 8 )); // 发送POST请求 HttpResponse httpResponse = httpClient.execute(post); // 如果服务器成功地返回响应 if (httpResponse.getStatusLine().getStatusCode() == 200 ) { // 获取服务器响应字符串 String result = EntityUtils.toString(httpResponse.getEntity()); return result; } return null ; } }

4.IntentService 服务，用于在后台以队列方式处理耗时操作。

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 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 /** * 经测试，IntentService里面是可以进行耗时的操作的 * IntentService使用队列的方式将请求的Intent加入队列， * 然后开启一个worker thread(线程)来处理队列中的Intent * 对于异步的startService请求，IntentService会处理完成一个之后再处理第二个 */ Boolean flag = false ; //通过intent获取主线程传来的用户名和密码字符串 String username = intent.getStringExtra(username); String password = intent.getStringExtra(password); flag = doLogin(username, password); Log.d(登录结果, flag.toString()); Intent broadcastIntent = new Intent(); broadcastIntent.setAction(ACTION_RECV_MSG); broadcastIntent.addCategory(Intent.CATEGORY_DEFAULT); broadcastIntent.putExtra(result, flag.toString()); sendBroadcast(broadcastIntent); } // 定义发送请求的方法 private Boolean doLogin(String username, String password) { String strFlag = ; // 使用Map封装请求参数 HashMap "" > map = new HashMap "" >(); map.put(un, username); map.put(pw, password); // 定义发送请求的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 { // 发送请求 strFlag = HttpUtil.postRequest(url, map); //POST方式 // strFlag = HttpUtil.getRequest(url); //GET方式 Log.d(服务器返回值, strFlag); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } if (strFlag.trim().equals( true )){ return true ; } else { return false ; } } }

5。在 AndroidManifest.xml 中注册 IntentService。注意 uses-permission 节点，为程序开启访问网络的权限。

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 "1" android:versionname= "1.0" package = "com.example.logindemo" xmlns:android= "https://schemas.android.com/apk/res/android" > "8" android:targetsdkversion= "18" > "android.permission.INTERNET" > "android.intent.category.LAUNCHER" > "com.example.logindemo.ConnectService" >

6. 登陆界面处理，注意

按钮监听事件中，使用 Intent 将要传递的值传给 service。接收广播类中，同样使用 Intent 将要传递的值传给下一个 Activity。在 onCreate() 中，动态注册接收广播类的实例 receiver。在接收广播类中，不要使用完毕后忘记注销接收器，否则会报一个 Are you missing a call to unregisterReceiver()? 的异常。

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 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(); //动态注册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()) { // 如果校验成功 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 , 账号不能为空,Toast.LENGTH_SHORT).show(); return false ; } if (passWord.equals()) { Toast.makeText(MainActivity. this , 密码不能为空,Toast.LENGTH_SHORT).show(); return false ; } return true ; } //接收广播类 public class MessageReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { String message = intent.getStringExtra(result); Log.i(MessageReceiver, message); // 如果登录成功 if (message.equals( true )){ // 启动Main Activity Intent nextIntent = new Intent(MainActivity. this , NaviActivity. class ); startActivity(nextIntent); // 结束该Activity finish(); //注销广播接收器 context.unregisterReceiver( this ); } else { Toast.makeText(MainActivity. this , 用户名或密码错误，请重新输入!,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 ; } }

运行截图：

转自：https://www.2cto.com/kf/201408/328118.html

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