正文
AsyncTask实现登录功能，上传图片，get，post
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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);
} }
