本文和大家一起了解了一下android客户端与服务端是怎样交互的，具体内容如下
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
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<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。
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<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。
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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。
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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。
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<!--?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。
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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; } } |
以上就是本文的全部内容，希望对大家的学习有所帮助。
