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
我要评论
<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 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。
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;
}
}
以上就是本文的全部内容，希望对大家的学习有所帮助。
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