本文参考：
首先要引入GreenDao，具体引用请参考本人的前面的博客，这里就不再写了；
废话完就要开始写了
首先要写一个User类：
@Entity public class User { @Id private Long id; private Integer thread_id; private Integer start_pos; private Integer end_pos; private Integer compelete_size; private String url;} 到这一步之后不要急不要慌，深呼吸然后运行一下子，看这个类和你的gen包都好了没，方方面面好了之后就开始粘贴下面的代码；
然后就先粘贴布局（这是本人多年粘贴代码的经验，先粘贴布局）
这个布局就非常简单了，在MainActivity的布局中粘贴
App
public class App extends Application { public static UserDao userDao; @Override public void onCreate() { super.onCreate(); DaoMaster.DevOpenHelper devOpenHelper = new DaoMaster.DevOpenHelper(this, "lenvess.db", null); DaoMaster daoMaster = new DaoMaster(devOpenHelper.getWritableDb()); DaoSession daoSession = daoMaster.newSession(); userDao = daoSession.getUserDao(); }} DownlaodSqlTool
public class DownlaodSqlTool { /** * 创建下载的具体信息 */ public void insertInfos(List infos) { for (DownloadInfo info : infos) { User user = new User(null, info.getThreadId(), info.getStartPos(), info.getEndPos(), info.getCompeleteSize(), info.getUrl()); userDao.insert(user); } } /** * 得到下载具体信息 */ public List getInfos(String urlstr) { List list = new ArrayList (); List list1 = userDao.queryBuilder().where(UserDao.Properties.Url.eq(urlstr)).build().list(); for (User user : list1) { DownloadInfo infoss = new DownloadInfo( user.getThread_id(), user.getStart_pos(), user.getEnd_pos(), user.getCompelete_size(), user.getUrl()); Log.d("main-----", infoss.toString()); list.add(infoss); } return list; } /** * 更新数据库中的下载信息 */ public void updataInfos(int threadId, int compeleteSize, String urlstr) { User user = userDao.queryBuilder() .where(UserDao.Properties.Thread_id.eq(threadId), UserDao.Properties.Url.eq(urlstr)).build().unique(); user.setCompelete_size(compeleteSize); userDao.update(user); } /** * 下载完成后删除数据库中的数据 */ public void delete(String url) { userDao.deleteAll(); }} DownloadHttpTool
public class DownloadHttpTool { /** * 利用Http协议进行多线程下载具体实践类 */ private static final String TAG = DownloadHttpTool.class.getSimpleName(); private int threadCount;//线程数量 private String urlstr;//URL地址 private Context mContext; private Handler mHandler; private List downloadInfos;//保存下载信息的类 private String localPath;//目录 private String fileName;//文件名 private int fileSize; private DownlaodSqlTool sqlTool;//文件信息保存的数据库操作类 private enum Download_State { Downloading, Pause, Ready;//利用枚举表示下载的三种状态 } private Download_State state = Download_State.Ready;//当前下载状态 private int globalCompelete = 0;//所有线程下载的总数 public DownloadHttpTool(int threadCount, String urlString, String localPath, String fileName, Context context, Handler handler) { super(); this.threadCount = threadCount; this.urlstr = urlString; this.localPath = localPath; this.mContext = context; this.mHandler = handler; this.fileName = fileName; sqlTool = new DownlaodSqlTool(); } //在开始下载之前需要调用ready方法进行配置 public void ready() { Log.w(TAG, "ready"); globalCompelete = 0; downloadInfos = sqlTool.getInfos(urlstr); if (downloadInfos.size() == 0) { initFirst(); } else { File file = new File(localPath + "/" + fileName); if (!file.exists()) { sqlTool.delete(urlstr); initFirst(); } else { fileSize = downloadInfos.get(downloadInfos.size() - 1) .getEndPos(); for (DownloadInfo info : downloadInfos) { globalCompelete += info.getCompeleteSize(); } Log.w(TAG, "globalCompelete:::" + globalCompelete); } } } public void start() { Log.w(TAG, "start"); if (downloadInfos != null) { if (state == Download_State.Downloading) { return; } state = Download_State.Downloading; for (DownloadInfo info : downloadInfos) { Log.v(TAG, "startThread"); new DownloadThread(info.getThreadId(), info.getStartPos(), info.getEndPos(), info.getCompeleteSize(), info.getUrl()).start(); } } } public void pause() { state = Download_State.Pause; } public void delete() { compelete(); File file = new File(localPath + "/" + fileName); file.delete(); } public void compelete() { sqlTool.delete(urlstr); } public int getFileSize() { return fileSize; } public int getCompeleteSize() { return globalCompelete; } //第一次下载初始化 private void initFirst() { Log.w(TAG, "initFirst"); try { URL url = new URL(urlstr); HttpURLConnection connection = (HttpURLConnection) url .openConnection(); connection.setConnectTimeout(5000); connection.setRequestMethod("GET"); fileSize = connection.getContentLength(); Log.w(TAG, "fileSize::" + fileSize); File fileParent = new File(localPath); if (!fileParent.exists()) { fileParent.mkdir(); } File file = new File(fileParent, fileName); if (!file.exists()) { file.createNewFile(); } // 本地访问文件 RandomAccessFile accessFile = new RandomAccessFile(file, "rwd"); accessFile.setLength(fileSize); accessFile.close(); connection.disconnect(); } catch (Exception e) { e.printStackTrace(); } int range = fileSize / threadCount; downloadInfos = new ArrayList (); for (int i = 0; i < threadCount - 1; i++) { DownloadInfo info = new DownloadInfo(i, i * range, (i + 1) * range - 1, 0, urlstr); downloadInfos.add(info); } DownloadInfo info = new DownloadInfo(threadCount - 1, (threadCount - 1) * range, fileSize - 1, 0, urlstr); downloadInfos.add(info); sqlTool.insertInfos(downloadInfos); } //自定义下载线程 private class DownloadThread extends Thread { private int threadId; private int startPos; private int endPos; private int compeleteSize; private String urlstr; private int totalThreadSize; public DownloadThread(int threadId, int startPos, int endPos, int compeleteSize, String urlstr) { this.threadId = threadId; this.startPos = startPos; this.endPos = endPos; totalThreadSize = endPos - startPos + 1; this.urlstr = urlstr; this.compeleteSize = compeleteSize; } @Override public void run() { HttpURLConnection connection = null; RandomAccessFile randomAccessFile = null; InputStream is = null; try { randomAccessFile = new RandomAccessFile(localPath + "/" + fileName, "rwd"); randomAccessFile.seek(startPos + compeleteSize); URL url = new URL(urlstr); connection = (HttpURLConnection) url.openConnection(); connection.setConnectTimeout(5000); connection.setRequestMethod("GET"); connection.setRequestProperty("Range", "bytes=" + (startPos + compeleteSize) + "-" + endPos); is = connection.getInputStream(); byte[] buffer = new byte[1024]; int length = -1; while ((length = is.read(buffer)) != -1) { randomAccessFile.write(buffer, 0, length); compeleteSize += length; Message message = Message.obtain(); message.what = threadId; message.obj = urlstr; message.arg1 = length; mHandler.sendMessage(message); sqlTool.updataInfos(threadId, compeleteSize, urlstr); Log.w(TAG, "Threadid::" + threadId + " compelete::" + compeleteSize + " total::" + totalThreadSize); if (compeleteSize >= totalThreadSize) { break; } if (state != Download_State.Downloading) { break; } } } catch (Exception e) { e.printStackTrace(); } finally { try { if (is != null) { is.close(); } randomAccessFile.close(); connection.disconnect(); } catch (Exception e) { e.printStackTrace(); } } } }} DownloadInfo
public class DownloadInfo { /** * 保存每个下载线程下载信息类 * */ private int threadId;// 下载器id private int startPos;// 开始点 private int endPos;// 结束点 private int compeleteSize;// 完成度 private String url;// 下载文件的URL地址 public DownloadInfo(int threadId, int startPos, int endPos, int compeleteSize, String url) { this.threadId = threadId; this.startPos = startPos; this.endPos = endPos; this.compeleteSize = compeleteSize; this.url = url; } public DownloadInfo() { } public String getUrl() { return url; } public void setUrl(String url) { this.url = url; } public int getThreadId() { return threadId; } public void setThreadId(int threadId) { this.threadId = threadId; } public int getStartPos() { return startPos; } public void setStartPos(int startPos) { this.startPos = startPos; } public int getEndPos() { return endPos; } public void setEndPos(int endPos) { this.endPos = endPos; } public int getCompeleteSize() { return compeleteSize; } public void setCompeleteSize(int compeleteSize) { this.compeleteSize = compeleteSize; } @Override public String toString() { return "DownloadInfo [threadId=" + threadId + ", startPos=" + startPos + ", endPos=" + endPos + ", compeleteSize=" + compeleteSize + "]"; }} DownloadUtil
public class DownloadUtil { private DownloadHttpTool mDownloadHttpTool; private OnDownloadListener onDownloadListener; private int fileSize; private int downloadedSize = 0; @SuppressLint("HandlerLeak") private Handler mHandler = new Handler() { @Override public void handleMessage(Message msg) { // TODO Auto-generated method stub super.handleMessage(msg); int length = msg.arg1; synchronized (this) { //加锁保证已下载的正确性 downloadedSize += length; } if (onDownloadListener != null) { onDownloadListener.downloadProgress(downloadedSize); } if (downloadedSize >= fileSize) { mDownloadHttpTool.compelete(); if (onDownloadListener != null) { onDownloadListener.downloadEnd(); } } } }; public DownloadUtil(int threadCount, String filePath, String filename, String urlString, Context context) { mDownloadHttpTool = new DownloadHttpTool(threadCount, urlString, filePath, filename, context, mHandler); } //下载之前首先异步线程调用ready方法获得文件大小信息，之后调用开始方法 public void start() { new AsyncTask () { @Override protected Void doInBackground(Void... arg0) { // TODO Auto-generated method stub mDownloadHttpTool.ready(); return null; } @Override protected void onPostExecute(Void result) { // TODO Auto-generated method stub super.onPostExecute(result); fileSize = mDownloadHttpTool.getFileSize(); downloadedSize = mDownloadHttpTool.getCompeleteSize(); Log.w("Tag", "downloadedSize::" + downloadedSize); if (onDownloadListener != null) { onDownloadListener.downloadStart(fileSize); } mDownloadHttpTool.start(); } }.execute(); } public void pause() { mDownloadHttpTool.pause(); } public void delete(){ mDownloadHttpTool.delete(); } public void reset(){ mDownloadHttpTool.delete(); start(); } public void setOnDownloadListener(OnDownloadListener onDownloadListener) { this.onDownloadListener = onDownloadListener; } //下载回调接口 public interface OnDownloadListener { public void downloadStart(int fileSize); public void downloadProgress(int downloadedSize);//记录当前所有线程下总和 public void downloadEnd(); }} MainActivity（！！注意，注意这是MainActivity不是自己创的类，不要粘贴错了）
public class MainActivity extends AppCompatActivity { private static final String TAG = MainActivity.class.getSimpleName(); private ProgressBar mProgressBar; private Button start; private Button pause; private TextView total; private int max; private DownloadUtil mDownloadUtil; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); total = (TextView) findViewById(R.id.textView); start = (Button) findViewById(R.id.start); pause = (Button) findViewById(R.id.delete); mProgressBar = (ProgressBar) findViewById(R.id.progressBar); String urlString = "http://2449.vod.myqcloud.com/2449_22ca37a6ea9011e5acaaf51d105342e3.f20.mp4"; String localPath = Environment.getExternalStorageDirectory() .getAbsolutePath() + "/local2"; mDownloadUtil = new DownloadUtil(2, localPath, "adc.mp4", urlString, this); mDownloadUtil.setOnDownloadListener(new DownloadUtil.OnDownloadListener() { @Override public void downloadStart(int fileSize) { // TODO Auto-generated method stub Log.w(TAG, "fileSize::" + fileSize); max = fileSize; mProgressBar.setMax(fileSize); } @Override public void downloadProgress(int downloadedSize) { // TODO Auto-generated method stub Log.w(TAG, "Compelete::" + downloadedSize); mProgressBar.setProgress(downloadedSize); total.setText((int) downloadedSize * 100 / max + "%"); } @Override public void downloadEnd() { // TODO Auto-generated method stub Log.w(TAG, "ENd"); } }); start.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View arg0) { // TODO Auto-generated method stub mDownloadUtil.start(); } }); pause.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View arg0) { // TODO Auto-generated method stub mDownloadUtil.pause(); } }); }} 这样代码方面就完事了；如果有报错一般是Handler的事这个千万记的倒OS那个包
然后就是权限：
如果运行了还报错，可能是你的App没有配，不要慌，仔细检查