android{useLibrary 'org.apache.http.legacy'
}

public static List<Activity> activityList = new LinkedList();

    public void exit()  {  for(Activity act:activityList)  {  act.finish();  }  System.exit(0);  }

MainActivity.activityList.add(this)

exit();

public class MainActivity extends Activity {Handler handler = new Handler(){@Overridepublic void handleMessage(Message msg) {Toast.makeText(MainActivity.this, (String)msg.obj, 0).show();}};@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);}public void get(View v){EditText et_name = (EditText) findViewById(R.id.et_name);EditText et_pass = (EditText) findViewById(R.id.et_pass);final String name = et_name.getText().toString();final String pass = et_pass.getText().toString();Thread t = new Thread(){@Overridepublic void run() {String path = "http://10.32.189.73:8080/d0301/LoginServlet?username=" + URLEncoder.encode(name) + "&password=" + pass;//使用httpClient框架做get方式提交//1.创建HttpClient对象HttpClient hc = new DefaultHttpClient();//2.创建httpGet对象，构造方法的参数就是网址HttpGet hg = new HttpGet(path);//3.使用客户端对象，把get请求对象发送出去try {HttpResponse hr = hc.execute(hg);//拿到响应头中的状态行StatusLine sl = hr.getStatusLine();if(sl.getStatusCode() == 200){//拿到响应头的实体HttpEntity he = hr.getEntity();//拿到实体中的内容，其实就是服务器返回的输入流InputStream is = he.getContent();String text = Utils.getTextFromStream(is);//发送消息，让主线程刷新ui显示textMessage msg = handler.obtainMessage();msg.obj = text;handler.sendMessage(msg);}} catch (Exception e) {// TODO Auto-generated catch block
                    e.printStackTrace();}}};t.start();}public void post(View v){EditText et_name = (EditText) findViewById(R.id.et_name);EditText et_pass = (EditText) findViewById(R.id.et_pass);final String name = et_name.getText().toString();final String pass = et_pass.getText().toString();Thread t = new Thread(){@Overridepublic void run() {String path = "http://10.32.189.73:8080/d0301/LoginServlet";//1.创建客户端对象HttpClient hc = new DefaultHttpClient();//2.创建post请求对象HttpPost hp = new HttpPost(path);//封装form表单提交的数据BasicNameValuePair bnvp = new BasicNameValuePair("username", name);BasicNameValuePair bnvp2 = new BasicNameValuePair("password", pass);List<BasicNameValuePair> parameters = new ArrayList<BasicNameValuePair>();//把BasicNameValuePair放入集合中
                parameters.add(bnvp);parameters.add(bnvp2);try {//要提交的数据都已经在集合中了，把集合传给实体对象UrlEncodedFormEntity entity = new UrlEncodedFormEntity(parameters, "utf-8");//设置post请求对象的实体，其实就是把要提交的数据封装至post请求的输出流中
                    hp.setEntity(entity);//3.使用客户端发送post请求HttpResponse hr = hc.execute(hp);if(hr.getStatusLine().getStatusCode() == 200){InputStream is = hr.getEntity().getContent();String text = Utils.getTextFromStream(is);//发送消息，让主线程刷新ui显示textMessage msg = handler.obtainMessage();msg.obj = text;handler.sendMessage(msg);}} catch (Exception e) {// TODO Auto-generated catch block
                    e.printStackTrace();}}};t.start();}
}

public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);}public void get(View v){EditText et_name = (EditText) findViewById(R.id.et_name);EditText et_pass = (EditText) findViewById(R.id.et_pass);final String name = et_name.getText().toString();final String pass = et_pass.getText().toString();String url = "http://10.32.189.73:8080/d0301/LoginServlet?username=" + URLEncoder.encode(name) + "&password=" + pass;//创建异步httpclientAsyncHttpClient ahc = new AsyncHttpClient();//发送get请求提交数据ahc.get(url, new MyResponseHandler());}public void post(View v){EditText et_name = (EditText) findViewById(R.id.et_name);EditText et_pass = (EditText) findViewById(R.id.et_pass);final String name = et_name.getText().toString();final String pass = et_pass.getText().toString();String url = "http://10.32.189.73:8080/d0301/LoginServlet";//创建异步httpclientAsyncHttpClient ahc = new AsyncHttpClient();//发送post请求提交数据//把要提交的数据封装至RequestParams对象RequestParams params = new RequestParams();params.add("username", name);params.add("password", pass);ahc.post(url, params, new MyResponseHandler());}class MyResponseHandler extends AsyncHttpResponseHandler {//请求服务器成功时，此方法调用
        @Overridepublic void onSuccess(int statusCode, org.apache.http.Header[] headers,byte[] responseBody) {Toast.makeText(MainActivity.this, new String(responseBody), Toast.LENGTH_SHORT).show();}//请求失败此方法调用
        @Overridepublic void onFailure(int statusCode, org.apache.http.Header[] headers,byte[] responseBody, Throwable error) {Toast.makeText(MainActivity.this, "请求失败", Toast.LENGTH_SHORT).show();}}
}

public class MainActivity extends AppCompatActivity {private static int ThreadCount = 3;private static int finishedThread = 0;public static List<Activity> activityList = new LinkedList();private String filepath= Environment.getExternalStorageDirectory()+"/ahmk/";private String downloadFilename=filepath+"test.zip";private static final String TAG = "MainActivity";int currentProgress;private int length;private String fileName = "test.zip";private static class Lock{};private static Object lock=new Lock();//确定下载地址private String path = "https://files.cnblogs.com/files/index42/" + fileName;private ProgressBar pb;TextView tv;Handler handler = new Handler() {public void handleMessage(android.os.Message msg) {//把变量改成long，在long下运算tv.setText((long) pb.getProgress() * 100 / pb.getMax() + "%");}};Handler handler2 = new Handler() {public void handleMessage(android.os.Message msg) {//把变量改成long，在long下运算tv.setText("文件已存在");}};@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);MainActivity.activityList.add(this);Log.e(TAG, filepath);pb = (ProgressBar) findViewById(R.id.pb);tv = (TextView) findViewById(R.id.tv);if (ContextCompat.checkSelfPermission(MainActivity.this,Manifest.permission.READ_EXTERNAL_STORAGE)!= PackageManager.PERMISSION_GRANTED  ){//申请权限ActivityCompat.requestPermissions(MainActivity.this,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE,Manifest.permission.READ_EXTERNAL_STORAGE},1);}else {//把动作告诉系统
}}public void click(View v) {Thread t = new Thread() {@Overridepublic void run() {//发送get请求，请求这个地址的资源try {File file = new File(downloadFilename);if(file.exists()) {handler2.sendEmptyMessage(1);Log.e(TAG, "已经存在文件");return;}URL url = new URL(path);HttpURLConnection conn = (HttpURLConnection) url.openConnection();conn.setRequestMethod("GET");conn.setConnectTimeout(5000);conn.setReadTimeout(5000);Log.e(TAG, conn.getResponseCode()+"");if (conn.getResponseCode() == 200) {//拿到所请求资源文件的长度length = conn.getContentLength();Log.e(TAG, length+"");//设置进度条的最大值就是原文件的总长度
                        pb.setMax(length);Log.e(TAG, "run3: ");File dir = new File(filepath);if(!dir.exists()){dir.mkdirs();}//生成临时文件BufferedRandomAccessFile raf = new BufferedRandomAccessFile(file, "rwd");//设置临时文件的大小
                        raf.setLength(length);raf.close();//计算出每个线程应该下载多少字节int size = length / ThreadCount;for (int i = 0; i < ThreadCount; i++) {//计算线程下载的开始位置和结束位置int startIndex = i * size;int endIndex = (i + 1) * size - 1;//如果是最后一个线程，那么结束位置写死if (i == ThreadCount - 1) {endIndex = length - 1;}
//                            System.out.println("线程" + i + "的下载区间是：" + startIndex + "---" + endIndex);new DownLoadThread(startIndex, endIndex, i).start();}}} catch (Exception e) {// TODO Auto-generated catch block
                    e.printStackTrace();}}};t.start();}class DownLoadThread extends Thread{int startIndex;int endIndex;int threadId;public DownLoadThread(int startIndex, int endIndex, int threadId) {super();this.startIndex = startIndex;this.endIndex = endIndex;this.threadId = threadId;}@Overridepublic void run() {//再次发送http请求，下载原文件try {File progressFile = new File(filepath,threadId + ".txt");//判断进度临时文件是否存在if(progressFile.exists()){FileInputStream fis = new FileInputStream(progressFile);BufferedReader br = new BufferedReader(new InputStreamReader(fis));//从进度临时文件中读取出上一次下载的总进度，然后与原本的开始位置相加，得到新的开始位置int lastProgress = Integer.parseInt(br.readLine());startIndex += lastProgress;//把上次下载的进度显示至进度条currentProgress += lastProgress;pb.setProgress(currentProgress);//发送消息，让主线程刷新文本进度handler.sendEmptyMessage(1);fis.close();}Log.e(TAG, "线程" + threadId + "的下载区间是：" + startIndex + "---" + endIndex);HttpURLConnection conn;URL url = new URL(path);conn = (HttpURLConnection) url.openConnection();conn.setRequestMethod("GET");conn.setConnectTimeout(5000);conn.setReadTimeout(5000);//设置本次http请求所请求的数据的区间conn.setRequestProperty("Range", "bytes=" + startIndex + "-" + endIndex);//请求部分数据，相应码是206if(conn.getResponseCode() == 206){//流里此时只有1/3原文件的数据InputStream is = conn.getInputStream();byte[] b = new byte[1024];int len = 0;int total = 0;//拿到临时文件的输出流File file = new File(downloadFilename);BufferedRandomAccessFile raf = new BufferedRandomAccessFile(file, "rwd");//把文件的写入位置移动至startIndex
                    raf.seek(startIndex);while((len = is.read(b)) != -1){//每次读取流里数据之后，同步把数据写入临时文件raf.write(b, 0, len);total += len;//Log.e(TAG, "线程" + threadId + "下载了" + total);//每次读取流里数据之后，把本次读取的数据的长度显示至进度条currentProgress += len;pb.setProgress(currentProgress);//发送消息，让主线程刷新文本进度handler.sendEmptyMessage(1);//生成一个专门用来记录下载进度的临时文件BufferedRandomAccessFile progressRaf = new BufferedRandomAccessFile(progressFile, "rwd");//每次读取流里数据之后，同步把当前线程下载的总进度写入进度临时文件中progressRaf.write((total + "").getBytes());progressRaf.close();}Log.e(TAG, "线程" + threadId + "下载完毕-------------------小志参上！");raf.close();finishedThread++;synchronized (lock) {Log.e(TAG, "synchron");if(finishedThread == ThreadCount){for (int i = 0; i < ThreadCount; i++) {File f = new File(filepath, i + ".txt");f.delete();}Log.e(TAG, "over synchron");finishedThread = 0;pb.setProgress(length);handler.sendEmptyMessage(1);}}}} catch (Exception e) {// TODO Auto-generated catch block
                e.printStackTrace();}}}public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {switch (requestCode){case 1://权限回调if (grantResults[0]==PackageManager.PERMISSION_GRANTED&&grantResults[1]==PackageManager.PERMISSION_GRANTED){}else {//提示用户权限未被授予Log.e("MainActivity","未授予权限");exit();}break;}}public void exit(){for(Activity act:activityList){act.finish();}System.exit(0);}
}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".MainActivity" android:orientation="vertical"><Buttonandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="开始下载" android:onClick="click"/><ProgressBar android:id="@+id/pb"android:layout_width="match_parent"android:layout_height="wrap_content"style="@android:style/Widget.ProgressBar.Horizontal"/><TextView android:id="@+id/tv"android:layout_width="wrap_content"android:layout_height="wrap_content"/>
</LinearLayout>

public class MainActivity extends Activity {private TextView tv_failure;private TextView tv_progress;private ProgressBar pb;public static List<Activity> activityList = new LinkedList();private static final String TAG = "MainActivity";@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);MainActivity.activityList.add(this);tv_failure = (TextView) findViewById(R.id.tv_failure);tv_progress = (TextView) findViewById(R.id.tv_progress);pb = (ProgressBar) findViewById(R.id.pb);if (ContextCompat.checkSelfPermission(MainActivity.this,Manifest.permission.READ_EXTERNAL_STORAGE)!= PackageManager.PERMISSION_GRANTED  ){//申请权限ActivityCompat.requestPermissions(MainActivity.this,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE,Manifest.permission.READ_EXTERNAL_STORAGE},1);}else {//把动作告诉系统
}}public void click(View v){HttpUtils utils = new HttpUtils();String fileName = "test.zip";//确定下载地址String path = "https://files.cnblogs.com/files/index42/" + fileName;String filepath= Environment.getExternalStorageDirectory()+"/ahmk/";String downloadFilename=filepath+"test.zip";File file = new File(downloadFilename);if(file.exists()) {tv_progress.setText("已经存在文件");Log.e(TAG, "已经存在文件");return;}utils.download(path, //下载地址downloadFilename, //文件保存路径true,//是否支持断点续传true, new RequestCallBack<File>() {//下载成功后调用
                    @Overridepublic void onSuccess(ResponseInfo<File> arg0) {Toast.makeText(MainActivity.this, arg0.result.getPath(), Toast.LENGTH_SHORT).show();}//下载失败调用
                    @Overridepublic void onFailure(HttpException arg0, String arg1) {// TODO Auto-generated method stub
                        tv_failure.setText(arg1);}@Overridepublic void onLoading(long total, long current,boolean isUploading) {// TODO Auto-generated method stubsuper.onLoading(total, current, isUploading);pb.setMax((int)total);pb.setProgress((int)current);tv_progress.setText(current * 100 / total + "%");}});}public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {switch (requestCode){case 1://权限回调if (grantResults[0]==PackageManager.PERMISSION_GRANTED&&grantResults[1]==PackageManager.PERMISSION_GRANTED){}else {//提示用户权限未被授予Log.e("MainActivity","未授予权限");exit();}break;}}public void exit(){for(Activity act:activityList){act.finish();}System.exit(0);}
}