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", ).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[], "utf-8")+"&pass="+URLEncoder.encode(params[], "utf-8");

                 //3.执行并得到回应
                 HttpResponse response=client.execute(new HttpGet(urlPath));

                 if(response.getStatusLine().getStatusCode()==)
                 {

                 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, ).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", ).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[]);
                 NameValuePair p = new BasicNameValuePair("pass",params[]);
                 parameters.add(n);
                 parameters.add(p);
                 Bitmap map=BitmapFactory.decodeResource(getResources(), R.drawable.myphoto);
                 ByteArrayOutputStream out=new ByteArrayOutputStream();
                 map.compress(Bitmap.CompressFormat.PNG, , out);

                 byte[] result=out.toByteArray();
             String img=    Base64.encodeToString(result, , 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()==)
                 {

                 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, ).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="" >

         <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=""
         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);
     }

 }