Android客户端与服务端交互之登陆示例

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。

<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" >

<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="40dp"
android:text="HelloWorld登陆示例" />

<EditText
android:id="@+id/et_user"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/textView1"
android:layout_centerHorizontal="true"
android:layout_marginTop="33dp"
android:ems="10"
android:hint="请输入账号" >

<requestFocus />
</EditText>

<EditText
android:id="@+id/et_psw"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/et_user"
android:layout_centerHorizontal="true"
android:layout_marginTop="40dp"
android:ems="10"
android:hint="请输入密码"
android:inputType="textPassword" />

<Button
android:id="@+id/btn_login"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/et_psw"
android:layout_centerHorizontal="true"
android:layout_marginTop="37dp"
android:text="登陆" />

</RelativeLayout>

<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=".NaviActivity" >

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="46dp"
android:text="登陆成功" />

</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;
}
}

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;
}

}
}

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 xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.logindemo"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="18" />

<uses-permission android:name="android.permission.INTERNET" />

<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.logindemo.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="com.example.logindemo.NaviActivity"
android:label="@string/title_activity_navi" >
</activity>

<service android:name="com.example.logindemo.ConnectService" >
</service>
</application>

</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;
}

}