android学习之访问互联网--服务端的登录验证
实现原理概述：通过客户端输入用户名和密码，然后提交到服务端进行验证的过程！因为考虑到是联系，数据较小，所以服务端的用户名与密码就存到list集合里面了！
首先，需要配置服务端的代码！这里是有sevlet来实现的：
package cn.cxrh.daomain;
import java.io.IOException;
import java.util.*;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.omg.CORBA.Request;
import cn.cxrh.daomain.*;
import com.sun.xml.internal.bind.v2.schemagen.xmlschema.List;
public class UserSer extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
boolean flag = false;
ArrayList<User> users =new ArrayList<User>();
users.add(new User("xiaobaima","123","2014-11-07 17:14:45"));
users.add(new User("xiaojiayu","345","2014-11-07 17:18:34"));
String username = new String(req.getParameter("username"));
String password = req.getParameter("password");
System.out.println("username=" + username);
System.out.println("password=" + password);
if(username != null && !"".equals(username) && password != null && !"".equals(password))
{
for(User user : users)
{
if(username.equals(user.getUsername()) && password.equals(user.getPassword())) 如果用户名与密码匹配的话
{
resp.getOutputStream().write("登录成功！".getBytes());//就给送这个数据给客户端
flag = true;
break;
}
}
if(!flag)
{
resp.getOutputStream().write("登录失败!".getBytes());
}
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
this.doGet(req, resp);
}
}
然后在客户单这边的话，就需要与服务端产生链接与交互：
首先是访问互联网的权限：
<uses-permission android:name="android.permission.INTERNET"/
然后在java代码里面写交互的代码：
public static byte[] loadDate(InputStream is) throws Exception
{ <font color="#2e8b57">//将服务端像客户端发来的输入流里面的数据转化为字节数组的形式</font>
ByteArrayOutputStream bos = new ByteArrayOutputStream();
byte[] buffer = new byte;
int len = -1;
while((len = is.read(buffer)) != -1)
{
bos.write(buffer,0,len);
}
is.close();
bos.close();
return bos.toByteArray();
}
首先要说明的是一般的写法有两种：
1.用HttpURLConnection实现：
其关键代码如下：
GET请求：
String path = "http://192.168.0.115:8080/qqServer/loginServlet?username=" +
URLEncoder.encode(username,"utf-8") + "&password="+URLEncoder.encode(password,"utf-8");
URL url = new URL(path);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");
conn.setConnectTimeout(5000);
int code = conn.getResponseCode();
if(code == 200)
{
InputStream is = conn.getInputStream();
return new String(loadDate(is),"GBK");
}POST请求：
String path="http://192.168.0.115:8080/qqServer/loginServlet";
String data = "username=" + URLEncoder.encode(username,"utf-8") +
"&password=" + URLEncoder.encode(password,"utf-8");
URL url = new URL(path);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();//获取链接的对象
conn.setRequestMethod("POST");
conn.setConnectTimeout(5000);
conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
conn.setRequestProperty("Content-Length", data.length()+"");
conn.setDoOutput(true);
conn.getOutputStream().write(data.getBytes());//获取输出流，将data的参数发出去
int code = conn.getResponseCode();//接收返回码
if(code == 200)
{
InputStream is = conn.getInputStream(); //通过链接对象获得输入流
return new String(loadDate(is),"GBK");
}
2.用HttpClient实现：
GET请求：
String path = "http://192.168.0.115:8080/qqServer/loginServlet?username=" +
URLEncoder.encode(username,"utf-8") + "&password=" + URLEncoder.encode(password,"utf-8");
HttpClient client = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(path);
HttpResponse response = client.execute(httpGet);
int code = response.getStatusLine().getStatusCode();
if(code == 200)
{
InputStream is = response.getEntity().getContent();
return new String(loadDate(is), "GBK");
}POST请求：
String path = "http://192.168.0.115:8080/qqServer/loginServlet";
HttpClient client=new DefaultHttpClient();
//创建请求路径的HttpGet对象
HttpPost httpPost=new HttpPost(path);
//建立一个List集合，集合中的类型为NameVluePair对象
List<NameValuePair> list=new ArrayList<NameValuePair>();
list.add(new BasicNameValuePair("username",username));
list.add(new BasicNameValuePair("password",password));
UrlEncodedFormEntity entity=new UrlEncodedFormEntity(list,"utf-8");
//设置实体数据
httpPost.setEntity(entity);
//让HttpClient往服务器发送数据
HttpResponse response=client.execute(httpPost);
//找到服务返回的状态码 200表示成功
int code=response.getStatusLine().getStatusCode();
if(code==200)
{
InputStream is=response.getEntity().getContent();
return new String(loadDate(is),"GBK");
}还有就是上面的方法可以通过开一个子线程，再接收返回来的数据，再将这个数据以消息的形式传给主线程，
这样的话，主线程就不会容易造成主线程的堵塞问题：
new Thread()
{
public void run()
{
String data = SendDataUtils.HttpPostSendData(username, password);
if(data != null)
{
Message msg = Message.obtain();
msg.what = 1;
msg.obj = data;
handler.sendMessage(msg);
}
}
}.start();
恩~~ 以上就是普通的实现方法，可是还有一种更加简单的实现方法就是，利用网上的一个开源框架来实现；
这需要在网上下载这个jar文件：android-async-http-1.4.5.jar；值得注意的是这个开源框架是基于阿帕奇服务的！！
其主要实现的代码如下：
GET请求的实现：
String url = "http://192.168.0.115:8080/qqServer/loginServlet?username=" +
URLEncoder.encode(username,"utf-8") + "&password="+URLEncoder.encode(password,"utf-8");
AsyncHttpClient client = new AsyncHttpClient();
client.get(url, new AsyncHttpResponseHandler() {
@Override
public void onSuccess(int arg0, Header[] arg1, byte[] arg2) {
// TODO Auto-generated method stub
try
{
Toast.makeText(MainActivity.this, new String(arg2,"GBK"), 0).show();
}catch(Exception e)
{
e.printStackTrace();
}
}
@Override
public void onFailure(int arg0, Header[] arg1, byte[] arg2, Throwable arg3) {
// TODO Auto-generated method stub
}
});POST请求的实现：
String url = "http://192.168.0.115:8080/qqServer/loginServlet";
username = URLEncoder.encode(username,"utf-8");
password = URLEncoder.encode(password,"utf-8");
AsyncHttpClient client = new AsyncHttpClient(); //异步http
RequestParams params = new RequestParams(); //请求参数
params.put("username", username); //将用户名设置进去
params.put("password", password);
client.post(url, params,new AsyncHttpResponseHandler() { //调用post方法
@Override
public void onSuccess(int arg0, Header[] arg1, byte[] arg2) { //回调方法
// TODO Auto-generated method stub
try
{
Toast.makeText(MainActivity.this, new String(arg2,"GBK"), 0).show();
}catch(Exception e)
{
e.printStackTrace();
}
}
@Override
public void onFailure(int arg0, Header[] arg1, byte[] arg2, Throwable arg3) {
// TODO Auto-generated method stub
}
});
:loveliness:既然进来了就要留脚印 支持下玄玄~ 请问下那个HTTPCLIENT 的url地址怎么请求的,我用android studio请求整天无法请求过去 哇 ，求 服务端教程
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