012_01HttpClient用户登录

　　HttpClient 是 Apache Jakarta Common 下的子项目，可以用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包，并且它支持 HTTP 协议最新的版本和建议。

　　

使用 HttpClient 需要以下 6 个步骤：

1. 创建 HttpClient 的实例

2. 创建某种连接方法的实例，在这里是 GetMethod。在 GetMethod 的构造函数中传入待连接的地址

3. 调用第一步中创建好的实例的 execute 方法来执行第二步中创建好的 method 实例

4. 读 response

5. 释放连接。无论执行方法是否成功，都必须释放连接

6. 对得到后的内容进行处理

MainActivity.java

package com.example.day12_01login;

import java.io.InputStream;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpEntity;
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 com.cskaoyan.webutils.WebUtils;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    Handler hanlder = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            // TODO Auto-generated method stub
            super.handleMessage(msg);
            
            switch (msg.what) {
            case 1:
                Toast.makeText(MainActivity.this, (String)msg.obj, 1).show();
                break;
            case 2:
                Toast.makeText(MainActivity.this, (String)msg.obj, 0).show();
                break;
            default:
                break;
            }
        }
    };
    
    
    //http client 的get请求
    public void login(View v){    
        EditText et_username = (EditText) findViewById(R.id.et_uername);
        EditText et_password = (EditText) findViewById(R.id.et_password);
        
        final String username= et_username.getText().toString();
        final String password= et_password.getText().toString();
        //http://localhost/LoginDemo/servlet/Login
        //发请求的线程
        Thread thread = new Thread(){
             public void run() {
                String path = "http://192.168.3.30/LoginDemo/servlet/Login?username="+URLEncoder.encode(username)+"&password="+password;
                HttpClient httpClient =null;
                try {
                    
                     httpClient = new DefaultHttpClient();
                    HttpGet httpget= new HttpGet(path);
                    
                    HttpResponse httpResponse =httpClient.execute(httpget);
                    
                    //conn.getResponseCode()==200
                    if(httpResponse.getStatusLine().getStatusCode()==200){
                        InputStream  is=httpResponse.getEntity().getContent();                        
                        String text = WebUtils.gettextFromInputStream(is, null);
                        Message msg = hanlder.obtainMessage();
                        msg.what=1;
                        msg.obj=text;
                        hanlder.sendMessage(msg);    
                    }
                    else {            
                        Message msg = hanlder.obtainMessage();
                        msg.what=2;
                        msg.obj="连接服务器失败";
                        hanlder.sendMessage(msg);                        
                    }        
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                finally{                    
                    if (httpClient!=null) {
                        httpClient.getConnectionManager().shutdown();     
                    }
                }
                
            };
        };
        thread.start();    
    }
    
    //http client Post 请求实现
    public void login2(View v){
        
        EditText et_username = (EditText) findViewById(R.id.et_uername);
        EditText et_password = (EditText) findViewById(R.id.et_password);
        
        final String username= et_username.getText().toString();
        final String password= et_password.getText().toString();
        
        //http://localhost/LoginDemo/servlet/Login
        //发请求的线程
        Thread thread = new Thread(){    
            public void run() {
                String path = "http://192.168.3.39/LoginDemo/servlet/Login";
                     //data = username=%E7%8E%8B%E9%81%93&password=123456
                String data = "username="+URLEncoder.encode(username)+"&password="+password;
                HttpClient httpClient = null;
                try {
                    httpClient = new DefaultHttpClient();
                    HttpPost   httpPost     = new HttpPost(path);
                    //HttpEntity httpEntity = new StringEntity(s);
                    List<NameValuePair> parameters = new ArrayList<NameValuePair>();
                    
                    NameValuePair namevp= new BasicNameValuePair("username",username );                    
                    parameters.add(namevp);
                    NameValuePair namevp2= new BasicNameValuePair("password",password );
                    parameters.add(namevp2);
                    HttpEntity httpEntity = new  UrlEncodedFormEntity(parameters,"utf-8");
                    httpPost.setEntity(httpEntity);
                    
                    HttpResponse httpResponse =httpClient.execute(httpPost);
                    if(httpResponse.getStatusLine().getStatusCode()==200){                    
                        InputStream  is= httpResponse.getEntity().getContent();
                        String text = WebUtils.gettextFromInputStream(is, null);
                        is.close();
                        Message msg = hanlder.obtainMessage();
                        msg.what=1;
                        msg.obj=text;
                        hanlder.sendMessage(msg);    
                    }
                    else {            
                        Message msg = hanlder.obtainMessage();
                        msg.what=2;
                        msg.obj="连接服务器失败";
                        hanlder.sendMessage(msg);                        
                    }                
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                finally{                    
                    if (httpClient!=null) {
                        httpClient.getConnectionManager().shutdown();     
                    }
                }    
            };
        };
        thread.start();    
    } 
}

activity_main.xml

<LinearLayout 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"
    tools:context="com.example.day12_01login.MainActivity"
    android:orientation="vertical" >

   
    <EditText
        android:id="@+id/et_uername"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" 
         />
    <EditText
        android:id="@+id/et_password"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" 
         />
    
    <RelativeLayout
         android:layout_width="fill_parent"
         android:layout_height="wrap_content" 
         >
        <CheckBox 
         android:id="@+id/cb_remeber"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content" 
         android:layout_alignParentLeft="true"
        />
        <Button
        android:id="@+id/bt_login"      
        android:layout_width="wrap_content"
         android:layout_height="wrap_content"  
         android:layout_alignParentRight="true"
         android:onClick="login"
                  android:text="get login"
        />
        
    </RelativeLayout>
 
       <RelativeLayout
         android:layout_width="fill_parent"
         android:layout_height="wrap_content" 
         >
        <CheckBox 
         android:id="@+id/cb_remeber2"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content" 
         android:layout_alignParentLeft="true"
        />
        <Button
        android:id="@+id/bt_login2"      
        android:layout_width="wrap_content"
         android:layout_height="wrap_content"  
         android:layout_alignParentRight="true"
         android:onClick="login2"
         android:text="post login"
        />
        
    </RelativeLayout>

         <Button
        android:id="@+id/bt_upload"      
        android:layout_width="wrap_content"
         android:layout_height="wrap_content"  
         android:layout_alignParentRight="true"
         android:onClick="upload"
                  android:text="uploadfile"
        />
</LinearLayout>

MyEclipse 创建的服务器端代码：

package com.example.login;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class Login extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        
        if("woodrow".equals(username)&&"123456".equals(password))
        {
            response.getWriter().write("登陆成功");
        }
        else {
            response.getWriter().write("登陆失败");
        }
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        this.doGet(request, response);
    }
}