诸位大神，这段代码我已经打了3次，每次都报异常（每次在启动service的），和解呀?

MainActivity中：

public class MainActivity extends Activity {
    private ProgressBar progressBar;
    private Button mBtStart,mBtStop;
    private static final String DOWNLOAD_PATH="kugoo://|Music|Chris Medina - What Are Words" +
            "|3000271|88bf6bc1a381c384af8858c6efdc6585|/";
    private static final String FileName="kugouSong.mp3";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        progressBar=(ProgressBar)findViewById(R.id.progressBarid);
        progressBar.setMax(100);
        mBtStart=(Button)findViewById(R.id.btstart);
        mBtStop=(Button)findViewById(R.id.btstop);    
        //创建文件信息对象
         final FileInfo fileInfo=new FileInfo(1,DOWNLOAD_PATH,FileName,0,0);
        mBtStart.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
               Intent intent=new Intent(MainActivity.this,DownloadService.class);
                 intent.setAction(DownloadService.ACTION_START);
                 intent.putExtra("fileInfo",fileInfo);
                startService(intent);
            }
        });
        mBtStop.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
               Intent intent=new Intent(MainActivity.this,DownloadService.class);
                 intent.setAction(DownloadService.ACTION_STOP);
                 intent.putExtra("fileInfo",fileInfo);
                startService(intent);
            }
        });

service类中：

public class DownloadService extends Service{
    public static final String ACTION_START="ACTION_START";
    public static final String ACTION_STOP="ACTION_STOP";
    public static final String ACTION_UPDATE="ACTION_UPDATE";
    //保存下载文件所到的路经
    public static final String SAVE_PATH=
            Environment.getExternalStorageDirectory().getAbsolutePath()+"/downloads/";
    public MyHandler myHandler;
    public static final int MSG_INIT=0;
    private DownloadTask mTask=null;
    
    @Override
    public IBinder onBind(Intent intent) {
        // TODO Auto-generated method stub
        return null;
    }
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        //实例化 MyHandler类
        myHandler=new MyHandler();
        if(ACTION_START.equals(intent.getAction())){        
            FileInfo fileInfo=(FileInfo)intent.getSerializableExtra("fileInfo");
            //启动初始化线程
            new InitThread(fileInfo).start();
        }else if(ACTION_STOP.equals(intent.getAction())){
            FileInfo fileInfo=(FileInfo)intent.getSerializableExtra("fileInfo");
            if(mTask!=null){
                mTask.isPause=true;
            }
        }
        return super.onStartCommand(intent, flags, startId);
    }
    @Override
    public void onDestroy() {
        // TODO Auto-generated method stub
        super.onDestroy();
    }    
    //继承 Handler
    public class MyHandler extends Handler{
        @Override
        public void handleMessage(Message msg) {
            // TODO Auto-generated method stub
            super.handleMessage(msg);
            switch(msg.what){
              case MSG_INIT:
                  FileInfo fileInfo=(FileInfo)msg.obj;
                  //启动下载任务
//                  mTask=new DownloadTask(DownloadService.this,fileInfo);
//                  mTask.download();
                 break;
            }
        }
    }
    /*
     * 初始化子线程
     */
    class InitThread extends Thread{
        private FileInfo mFileInfo=null;
        public InitThread(FileInfo mfileInfo){
            this.mFileInfo=mfileInfo;
        }
        public void run() {
            HttpURLConnection conn=null;
            RandomAccessFile raf=null;
            try{
               //链接网络文件
                URL url=new URL(mFileInfo.geturl());
                 conn=(HttpURLConnection)url.openConnection();
                 conn.setConnectTimeout(5000);
                 conn.setRequestMethod("GET");
                int length=-1;
                if(conn.getResponseCode()==200){
                   //获得文件长度
                    length=conn.getContentLength();
                }
                if(length<=0){
                    return;
                }
                //在本地创建文件
                File dir=new File(SAVE_PATH);
                if(!dir.exists()){
                    dir.mkdir();
                }
                File file=new File(dir,mFileInfo.getfileName());
                raf=new RandomAccessFile(file,"rwd");
                raf.setLength(length);
                
                //设置文件长度,用MyHandler的对象传递Message到被继承的Handler方法中
                mFileInfo.setlength(length);
                Message message=Message.obtain();
                 message.what=MSG_INIT;
                 message.obj=mFileInfo;
                 myHandler.sendMessage(message);
            }catch(Exception e){
                e.printStackTrace();
            }finally{
                try {
                    raf.close();
                    conn.disconnect();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    }