- Android客户端与服务端交互之登陆示例
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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
<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 <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">
2
3 <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登陆示例"> <edittext
android:ems="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"> <requestfocus>
</requestfocus>
</edittext> <edittext
android:ems="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"> <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="登陆">
</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="登陆成功"> </textview></relativelayout>3.HTTP的访问公共类，用于处理GET和POST请求
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 {
// 创建HttpClient对象
public static HttpClient httpClient = new DefaultHttpClient();
public static final String BASE_URL = http://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<string, string=""> 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<namevaluepair> params = new ArrayList<namevaluepair>();
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;
}
}
</namevaluepair></namevaluepair></string,>4.IntentService服务，用于在后台以队列方式处理耗时操作。
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
/**
* 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<string, string=""> map = new HashMap<string, string="">();
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;
} }
}
</string,></string,>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。
<!--?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。
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：
- 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。