Android的断点续传的下载在线文件示例 _android

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android的断点续传的下载在线文件示例
文件的结构如下:
activity_main.xml:

< 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" android:orientation="vertical" tools:context=".MainActivity" > < EditText android:id="@+id/et_path" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="http://localhost:8080/gh.zip" android:hint="请输入下载路径" tools:ignore="HardcodedText" /> < EditText android:id="@+id/et_threadCount" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="请输入线程的数量" /> < Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="click" android:text="下载" /> < LinearLayout android:id="@+id/ll_pb" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > < /LinearLayout> < /LinearLayout>

【Android的断点续传的下载在线文件示例】item.xml:

< ?xml version="1.0" encoding="utf-8"?> < ProgressBar xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/progressBar1" style="?android:attr/progressBarStyleHorizontal" android:layout_width="match_parent" android:layout_height="wrap_content" />

network_security_config.xml:

< ?xml version="1.0" encoding="utf-8"?> < network-security-config> < base-config cleartextTrafficPermitted="true" /> < /network-security-config>

AndroidManifest.xml:

< ?xml version="1.0" encoding="utf-8"?> < manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.administrator.fdtest"> < uses-permission android:name="android.permission.INTERNET"> < /uses-permission> < uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"> < /uses-permission> < uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> < application android:usesCleartextTraffic="true" android:networkSecurityConfig="@xml/network_security_config" android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:roundIcon="@mipmap/ic_launcher_round" android:supportsRtl="true" android:theme="@style/AppTheme"> < activity android:name=".MainActivity"> < intent-filter> < action android:name="android.intent.action.MAIN" /> < category android:name="android.intent.category.LAUNCHER" /> < /intent-filter> < /activity> < /application> < /manifest>

MainActivity:

package com.example.administrator.fdtest; import java.io.BufferedReader; import java.io.File; import java.io.FileInputStream; import java.io.InputStream; import java.io.InputStreamReader; import java.io.RandomAccessFile; import java.net.HttpURLConnection; import java.net.URL; import java.util.ArrayList; import java.util.List; import android.Manifest; import android.content.pm.PackageManager; import android.os.Bundle; import android.os.Environment; import android.app.Activity; import android.support.v4.app.ActivityCompat; import android.view.Menu; import android.view.View; import android.widget.EditText; import android.widget.LinearLayout; import android.widget.ProgressBar; public class MainActivity extends Activity {private EditText et_path; private EditText et_threadCount; private LinearLayout ll_pb_layout; private String path; private static int runningThread; //代表当前正在运行的线程 private int threadCount; private List< ProgressBar> pbLists; //用来存进度条的引用privatefinal int REQUEST_EXTERNAL_STORAGE = 1; privateString[] PERMISSIONS_STORAGE = { Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.WRITE_EXTERNAL_STORAGE }; publicvoid verifyStoragePermissions(Activity activity) { // Check if we have write permission int permission = ActivityCompat.checkSelfPermission(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE); if (permission != PackageManager.PERMISSION_GRANTED) { // We don\'t have permission so prompt the user ActivityCompat.requestPermissions(activity, PERMISSIONS_STORAGE, REQUEST_EXTERNAL_STORAGE); } }@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); verifyStoragePermissions(this); // [1]找到我们关心的控件et_path = (EditText) findViewById(R.id.et_path); et_threadCount = (EditText) findViewById(R.id.et_threadCount); ll_pb_layout = (LinearLayout) findViewById(R.id.ll_pb); //[2]添加一个集合用来存进度条的引用 pbLists = new ArrayList< ProgressBar> (); }//点击按钮实现下载的逻辑 public void click(View v){//[2]获取下载的路径//path = et_path.getText().toString().trim(); path = "http://localhost:8080/gh.zip"; //[3]获取线程的数量 String threadCountt= et_threadCount.getText().toString().trim(); //[3.0]先移除进度条在添加 ll_pb_layout.removeAllViews(); threadCount = Integer.parseInt(threadCountt); pbLists.clear(); for (int i = 0; i < threadCount; i++) {//[3.1]把我定义的item布局转换成一个view对象 ProgressBar pbView = (ProgressBar) View.inflate(getApplicationContext(), R.layout.item, null); //[3.2]把pbView 添加到集合中 pbLists.add(pbView); //[4]动态的添加进度条 ll_pb_layout.addView(pbView); }//[5]开始移植联网获取文件长度 new Thread(){public void run() {//[一 ☆☆☆☆]获取服务器文件的大小要计算每个线程下载的开始位置和结束位置try {//(1) 创建一个url对象参数就是网址 URL url = new URL(path); //(2)获取HttpURLConnection 链接对象 HttpURLConnection conn = (HttpURLConnection) url.openConnection(); //(3)设置参数发送get请求 conn.setRequestMethod("GET"); //默认请求就是get要大写 //(4)设置链接网络的超时时间 conn.setConnectTimeout(5000); //(5)获取服务器返回的状态码 int code = conn.getResponseCode(); //200代表获取服务器资源全部成功206请求部分资源 if (code == 200) {//(6)获取服务器文件的大小 int length = conn.getContentLength(); //[6.1]把线程的数量赋值给正在运行的线程 runningThread = threadCount; System.out.println("length:"+length); //[二☆☆☆☆ ] 创建一个大小和服务器一模一样的文件目的提前把空间申请出来 RandomAccessFile rafAccessFile = new RandomAccessFile(getFilename(path), "rw"); rafAccessFile.setLength(length); //(7)算出每个线程下载的大小 int blockSize = length /threadCount; //[三☆☆☆☆计算每个线程下载的开始位置和结束位置 ] for (int i = 0; i < threadCount; i++) { int startIndex = i * blockSize; //每个线程下载的开始位置 int endIndex = (i+1)*blockSize - 1; //特殊情况就是最后一个线程 if (i == threadCount - 1) { //说明是最后一个线程 endIndex = length - 1; }System.out.println("线程id:::"+i + "理论下载的位置"+":"+startIndex+"-----"+endIndex); //四开启线程去服务器下载文件 DownLoadThread downLoadThread = new DownLoadThread(startIndex, endIndex, i); downLoadThread.start(); }}} catch (Exception e) { e.printStackTrace(); } }; }.start(); }//定义线程去服务器下载文件 privateclass DownLoadThread extends Thread{ //通过构造方法把每个线程下载的开始位置和结束位置传递进来private int startIndex; private int endIndex; private int threadId; private int PbMaxSize; //代表当前线程下载的最大值 //如果中断过获取上次下载的位置 private int pblastPostion; public DownLoadThread(int startIndex,int endIndex,int threadId){ this.startIndex = startIndex; this.endIndex= endIndex; this.threadId = threadId; }@Override public void run() { //四实现去服务器下载文件的逻辑try { //(0)计算当前进度条的最大值 PbMaxSize = endIndex - startIndex; //(1) 创建一个url对象参数就是网址 URL url = new URL(path); //(2)获取HttpURLConnection 链接对象 HttpURLConnection conn = (HttpURLConnection) url .openConnection(); //(3)设置参数发送get请求 conn.setRequestMethod("GET"); //默认请求就是get要大写 //(4)设置链接网络的超时时间 conn.setConnectTimeout(5000); //[4.0]如果中间断过继续上次的位置继续下载从文件中读取上次下载的位置File file =new File(getFilename(path)+threadId+".txt"); if (file.exists() & & file.length()> 0) { FileInputStream fis = newFileInputStream(file); BufferedReader bufr = newBufferedReader(new InputStreamReader(fis)); String lastPositionn = bufr.readLine(); //读取出来的内容就是上一次下载的位置 int lastPosition = Integer.parseInt(lastPositionn); //[4.0]给我们定义的进度条条位置赋值 pblastPostion = lastPosition - startIndex; //[4.0.1]要改变一下 startIndex 位置 startIndex = lastPosition + 1; System.out.println("线程id::"+threadId + "真实下载的位置"+":"+startIndex+"-----"+endIndex); fis.close(); //关闭流 }//[4.1]设置一个请求头Range (作用告诉服务器每个线程下载的开始位置和结束位置) conn.setRequestProperty("Range", "bytes="+startIndex+"-"+endIndex); //(5)获取服务器返回的状态码 int code = conn.getResponseCode(); //200代表获取服务器资源全部成功206请求部分资源成功 if (code == 206) { //[6]创建随机读写文件对象 RandomAccessFile raf = new RandomAccessFile(getFilename(path), "rw"); //[6]每个线程要从自己的位置开始写 raf.seek(startIndex); InputStream in = conn.getInputStream(); //存的是feiq.exe//[7]把数据写到文件中 int len = -1; byte[] buffer = new byte[1024*1024]; //1Mbint total = 0; //代表当前线程下载的大小while((len = in.read(buffer))!=-1){ raf.write(buffer, 0, len); total +=len; //[8]实现断点续传就是把当前线程下载的位置给存起来下次再下载的时候就是按照上次下载的位置继续下载就可以了 int currentThreadPosition =startIndex + total; //比如就存到一个普通的.txt文本中//[9]用来存当前线程下载的位置 RandomAccessFile raff = new RandomAccessFile(getFilename(path)+threadId+".txt", "rwd"); raff.write(String.valueOf(currentThreadPosition).getBytes()); raff.close(); //[10]设置一下当前进度条的最大值和当前进度 pbLists.get(threadId).setMax(PbMaxSize); //设置进度条的最大值 pbLists.get(threadId).setProgress(pblastPostion+total); //设置当前进度条的当前进度 } raf.close(); //关闭流释放资源System.out.println("线程id:"+threadId + "---下载完毕了"); //[10]把.txt文件删除每个线程具体什么时候下载完毕了我们不知道synchronized (DownLoadThread.class) { runningThread--; if (runningThread == 0) { //说明所有的线程都执行完毕了就把.txt文件删除 for (int i = 0; i < threadCount; i++) { FiledelteFile = new File(getFilename(path)+i+".txt"); delteFile.delete(); } } } }} catch (Exception e) { e.printStackTrace(); } } }//获取文件的名字 publicString getFilename(String path){int start =path.lastIndexOf("/")+1; String substring = path.substring(start); String fileName = Environment.getExternalStorageDirectory().getPath()+"/"+substring; return fileName; } }