如何在android里头执行adb shell命令

package net.gimite.nativeexe;

import java.io.BufferedReader;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import net.gimite.nativeexe.R;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.*;

public class MainActivity extends Activity {

private TextView outputView;
private Button localRunButton;
private EditText localPathEdit;
private Handler handler = new Handler();
private EditText urlEdit;
private Button remoteRunButton;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

outputView = (TextView)findViewById(R.id.outputView);
localPathEdit = (EditText)findViewById(R.id.localPathEdit);
localRunButton = (Button)findViewById(R.id.localRunButton);
localRunButton.setOnClickListener(onLocalRunButtonClick);

}

private OnClickListener onLocalRunButtonClick = new OnClickListener() {
public void onClick(View v) {
String output = exec(localPathEdit.getText().toString());
output(output);
// try {
//
// // Process process = Runtime.getRuntime().exec(localPathEdit.getText().toString());
//
// } catch (IOException e) {
// // TODO Auto-generated catch block
// e.printStackTrace();
// }
}
};

// Executes UNIX command.
private String exec(String command) {
try {
Process process = Runtime.getRuntime().exec(command);
BufferedReader reader = new BufferedReader(
new InputStreamReader(process.getInputStream()));
int read;
char[] buffer = new char[4096];
StringBuffer output = new StringBuffer();
while ((read = reader.read(buffer)) > 0) {
output.append(buffer, 0, read);
}
reader.close();
process.waitFor();
return output.toString();
} catch (IOException e) {
throw new RuntimeException(e);
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
}

private void download(String urlStr, String localPath) {
try {
URL url = new URL(urlStr);
HttpURLConnection urlconn = (HttpURLConnection)url.openConnection();
urlconn.setRequestMethod("GET");
urlconn.setInstanceFollowRedirects(true);
urlconn.connect();
InputStream in = urlconn.getInputStream();
FileOutputStream out = new FileOutputStream(localPath);
int read;
byte[] buffer = new byte[4096];
while ((read = in.read(buffer)) > 0) {
out.write(buffer, 0, read);
}
out.close();
in.close();
urlconn.disconnect();
} catch (MalformedURLException e) {
throw new RuntimeException(e);
} catch (IOException e) {
throw new RuntimeException(e);
}
}

private void output(final String str) {
Runnable proc = new Runnable() {
public void run() {
outputView.setText(str);
}
};
handler.post(proc);
}

}

期待看到有用的回答！