AsyncTask实现登录功能，上传图片，get，post

提交成功时，从服务器端返回数据“load success”

用户名、密码正确后成功登录，并且在服务器端的文件保存目录上看到了从客户端上传的图片。

客户端代码：

MainActivity.java

import java.io.ByteArrayOutputStream;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.List;

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.app.Activity;
import android.app.ProgressDialog;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.text.TextUtils;
import android.util.Base64;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class Activity2 extends Activity {

    private ProgressDialog dialog;
    private EditText name;
    private EditText pass;
    private Context context;
    private static final String PATH="http://172.16.30.146:8080/Lesson/servlet/LoginServlet?";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main2);
        context=this;
        name=(EditText) findViewById(R.id.name);
        pass=(EditText) findViewById(R.id.pass);
        dialog= new ProgressDialog(context);
        dialog.setCancelable(false);
        dialog.setTitle("提示");
        dialog.setMessage("下载中,请稍等.....");
        dialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
        
        
        
    }
    
    public void myget(View v)
    {
        String myname=name.getText().toString().trim();
        String mypass=pass.getText().toString().trim();
        if(TextUtils.isEmpty(myname) || TextUtils.isEmpty(mypass))
        {
            Toast.makeText(context, "用户名或密码不能为空", 1).show();
            return;
        }
        
        new MyGetTask().execute(myname,mypass);
    }

    /*采用异步任务
     * 参数一代表 执行异步任务时传递的参数的类型
     * 参数二 如果不采用进度，则填Void,否则填 Integer
     * 参数三 是指网络回传回来的数据类型
     */
    public class MyGetTask extends AsyncTask<String,Void,String>{

        @Override
        protected void onPreExecute() {
            dialog.show();
            super.onPreExecute();
        }
        @Override
        protected String doInBackground(String... params) {
            //1.打开浏览器
            HttpClient client=new DefaultHttpClient();
            //2.输入网址
            String urlPath=null;
            try {
                urlPath=PATH+"name="+URLEncoder.encode(params[0], "utf-8")+"&pass="+URLEncoder.encode(params[1], "utf-8");
            
                //3.执行并得到回应
                HttpResponse response=client.execute(new HttpGet(urlPath));
            
                if(response.getStatusLine().getStatusCode()==200)
                {
                    
                String str=    EntityUtils.toString(response.getEntity());
                return str;
                }
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            
        
            return null;
        }
        
        @Override
        protected void onPostExecute(String result) {
            dialog.dismiss();
            Toast.makeText(context, "得到的回应是："+result, 1).show();
            
            super.onPostExecute(result);
        }
        
    }
    
    
    public void mypost(View v)
    {
        String myname=name.getText().toString().trim();
        String mypass=pass.getText().toString().trim();
        if(TextUtils.isEmpty(myname) || TextUtils.isEmpty(mypass))
        {
            Toast.makeText(context, "用户名或密码不能为空", 1).show();
            return;
        }
        
        new MyTaskByPost().execute(myname,mypass);
        
/*        
        */    
    }
   
    public class MyTaskByPost extends AsyncTask<String, Void, String>{

        //Volley  AsyncHttpClient

        @Override
        protected void onPreExecute() {
            dialog.show();
            super.onPreExecute();
        }
        @Override
        protected String doInBackground(String... params) {
            //1.打开浏览器
            HttpClient client=new DefaultHttpClient();
            //2.输入网址
            String urlPath="http://172.16.30.146:8080/Lesson/servlet/LoginServlet";
            try {
                //3.设置向服务器提交的数据
                List<NameValuePair> parameters=new ArrayList();
                NameValuePair n = new BasicNameValuePair("name",params[0]);
                NameValuePair p = new BasicNameValuePair("pass",params[1]);
                parameters.add(n);
                parameters.add(p);
                Bitmap map=BitmapFactory.decodeResource(getResources(), R.drawable.myphoto);
                ByteArrayOutputStream out=new ByteArrayOutputStream();
                map.compress(Bitmap.CompressFormat.PNG, 100, out);
                
                byte[] result=out.toByteArray();
            String img=    Base64.encodeToString(result, 0, result.length, Base64.DEFAULT);
            
                NameValuePair m = new BasicNameValuePair("img",img);
                parameters.add(m);
                
            UrlEncodedFormEntity    entity = new UrlEncodedFormEntity(parameters, "utf-8");
                
            HttpPost httpPost = new HttpPost(urlPath);
            httpPost.setEntity(entity);
                //3.执行并得到回应
                HttpResponse response=client.execute(httpPost);
            
                if(response.getStatusLine().getStatusCode()==200)
                {
                    
                String str=    EntityUtils.toString(response.getEntity());
                return str;
                }
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            
        
            return null;
        }
        @Override
        protected void onPostExecute(String result) {
            dialog.dismiss();
            Toast.makeText(context, "得到的回应是："+result, 1).show();
            
            super.onPostExecute(result);
        }
    }

}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginLeft="36dp"
        android:layout_marginTop="58dp"
        android:text="用户名" />

    <EditText
        android:id="@+id/name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/textView1"
        android:layout_alignBottom="@+id/textView1"
        android:layout_marginLeft="53dp"
        android:layout_toRightOf="@+id/textView1"
        android:ems="10" >

        <requestFocus />
    </EditText>

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/textView1"
        android:layout_below="@+id/name"
        android:layout_marginTop="49dp"
        android:text="密码" />

    <EditText
        android:id="@+id/pass"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/textView2"
        android:layout_alignLeft="@+id/name"
        android:ems="10"
        android:inputType="textPassword" />

    <Button
        android:id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_below="@+id/textView2"
        android:layout_marginTop="33dp"
        android:onClick="myget"
        android:text="get方式向服务器提交数据" />

    <Button
        android:id="@+id/button2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_below="@+id/button1"
        android:layout_marginTop="33dp"
        android:onClick="mypost"
        android:text="post方式向服务器提交数据" />

</RelativeLayout>

清单里注册权限：<uses-permission android:name="android.permission.INTERNET"/>

服务器端代码：

新建Servlet: LoginServlet.java

package com.my.android;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import sun.misc.BASE64Decoder;

/**
 * Servlet implementation class LoginServlet
 */
public class LoginServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {

        response.setContentType("text/html;charset=utf-8");
        response.setCharacterEncoding("utf-8");

        request.setCharacterEncoding("utf-8");
        String myname = request.getParameter("name");
        String mypass = request.getParameter("pass");
        PrintWriter writer = response.getWriter();
        System.out.println("myname=" + myname + " mypass=" + mypass);
        
         
         

        String img = request.getParameter("img");
        byte[] b = new BASE64Decoder().decodeBuffer(img);
        File file = new File("F:", "myphoto.png");
        if (!file.exists())
            file.createNewFile();
        OutputStream myout = new FileOutputStream(file);
        myout.write(b);
        myout.close();
        
        
        
        writer.write("load success");
        writer.flush();
        writer.close();
    

    }

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

}