Android应用客户端自动升级
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import android.app.AlertDialog;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
public class Update extends BaseActivity {
 public ProgressDialog pBar;
 private Handler handler = new Handler();
@Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.update);
  Dialog dialog = new AlertDialog.Builder(Update.this).setTitle("系统更新")
    .setMessage("发现新版本,请更新!")// 设置内容
    .setPositiveButton("确定",// 设置确定按钮
      new DialogInterface.OnClickListener() {
@Override
       public void onClick(DialogInterface dialog,
         int which) {
        pBar = new ProgressDialog(Update.this);
        pBar.setTitle("正在下载");
        pBar.setMessage("请稍候...");
        pBar
          .setProgressStyle(ProgressDialog.STYLE_SPINNER);
        downFile(":8765/OA.apk");
        
}
}).setNegativeButton("取消", 
      new DialogInterface.OnClickListener() {
       public void onClick(DialogInterface dialog,
         int whichButton) {
        // 点击"取消"按钮之后退出程序
        
       }
      }).create();// 创建
  // 显示对话框
  dialog.show();
}
void downFile(final String url) {
  pBar.show();
  new Thread() {
   public void run() {
    HttpClient client = new DefaultHttpClient();
    // params[0]代表连接的url
    HttpGet get = new HttpGet(url);
    HttpResponse response;
    try {
     response = client.execute(get);
     HttpEntity entity = response.getEntity();
     long length = entity.getContentLength();
     InputStream is = entity.getContent();
     FileOutputStream fileOutputStream = null;
     if (is != null) {
File file = new File(Environment
        .getExternalStorageDirectory(), "OA.apk");
      fileOutputStream = new FileOutputStream(file);
      
      byte[] buf = new byte[1024];
      int ch = -1;
      int count = 0;
      while ((ch = is.read(buf)) != -1) {
       // baos.write(buf, 0, ch);
       fileOutputStream.write(buf, 0, ch);
       count += ch;
       if (length > 0) {
       
       }
}
}
     fileOutputStream.flush();
     if (fileOutputStream != null) {
      fileOutputStream.close();
     }
     down();
    } catch (ClientProtocolException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
    } catch (IOException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
    }
   }
}.start();
}
void down() {
  handler.post(new Runnable() {
   public void run() {
    pBar.cancel();
    update();
   }
  });
}
void update() {
