010_04用户登录（用户名，密码交给服务器并验证）

　　该代码主要使用了get和post两种方式提交数据到服务器

　　将常用的代码块封装成工具类一提高代码的重用性。

package com.cskaoyan.webutils;

import java.io.ByteArrayOutputStream;
import java.io.InputStream;

public class WebUtils {

    public static String gettextFromInputStream(InputStream is ,String charset){
        String text = null;
    
        if(charset==null){
            charset="utf-8";
        }
        try {
            ByteArrayOutputStream baos= new ByteArrayOutputStream();    
            byte[] b = new byte[1024];
            int len = 0;
            while ((len=is.read(b))!=-1) {
                baos.write(b, 0, len);                            
            }
            baos.close();            
            text = new String(baos.toByteArray(), charset);            
        } catch (Exception e) {
            e.printStackTrace();
        }
        return  text;
    }
}

MainActivity.java

package com.example.day10_04login;

import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
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) {
            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;
            }
        }    
    };
    
    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();    

        //发请求的线程
        Thread thread = new Thread(){    
            public void run() {
                String path = "http://192.168.3.30:8080/LoginDemo/servlet/Login?username="
                        +URLEncoder.encode(username)+"&password="+password;
                try {
                    URL url = new URL(path);
                    HttpURLConnection conn= (HttpURLConnection) url.openConnection();
                    conn.setReadTimeout(5000);
                    conn.setConnectTimeout(5000);    
                    conn.setRequestMethod("GET");
                    conn.connect();
                    
                    if(conn.getResponseCode()==200){
                        InputStream  is= conn.getInputStream();
                        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) {
                    e.printStackTrace();
                }    
            };
        };
        thread.start();    
    }
    
    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://192.168.3.30:8080/LoginDemo/servlet/Login";
                     //data = username=%E7%8E%8B%E9%81%93&password=123456
                String data = "username="+URLEncoder.encode(username)+"&password="+password;
                try {
                    URL url = new URL(path);
                    HttpURLConnection conn= (HttpURLConnection) url.openConnection();
                    //发送请求的三个参数
                    conn.setReadTimeout(5000);
                    conn.setConnectTimeout(5000);                    
                    conn.setRequestMethod("POST");
                    //使用post提交的时候需要设置的两参数正文发送数据的长度及类型
                    conn.setRequestProperty("content-Length", data.length()+"");
                    conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");                    
                    //将data 放到request的请求正文
                    conn.setDoOutput(true);
                    OutputStream os = conn.getOutputStream();
                    os.write(data.getBytes());
                    //向服务器发送链接
                    conn.connect();
                    
                    if(conn.getResponseCode()==200){
                        InputStream  is= conn.getInputStream();
                        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) {
                    e.printStackTrace();
                }                
            };
        };
        thread.start();    
    }     
}

activity_main.java

<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.day10_04login.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>

</LinearLayout>

使用MyEclipse创建一个web project，并将该project部署到tomcat上。其中servlet代码如下：

Login.java

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");
        
//           byte[] b=  username.getBytes("iso-8859-1"); 
//           username =  new String(b, "utf-8");
        
        //woodrow 123456
        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);
    }
}

效果图：