多线程下载Android

多线程下载

1.新建:MultiDownloader\app\src\main\res\xml\network_security_config.xml

配置支持HTTP请求

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

2. AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"package="com.glsite.multidownloader"><uses-permission android:name="android.permission.INTERNET"/><applicationandroid: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"android:networkSecurityConfig="@xml/network_security_config"><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>

3.新建MultiDownloader\app\src\main\res\layout\pb.xml

进度条

<?xml version="1.0" encoding="utf-8"?>
<ProgressBar xmlns:android="http://schemas.android.com/apk/res/android"style="@style/Widget.AppCompat.ProgressBar.Horizontal"android:layout_width="match_parent"android:layout_height="match_parent"></ProgressBar>

4.activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".MainActivity"><EditTextandroid:id="@+id/et_threadcount"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_marginStart="8dp"android:layout_marginLeft="8dp"android:layout_marginTop="36dp"android:layout_marginEnd="8dp"android:layout_marginRight="8dp"android:ems="10"android:hint="请输入下载线程的数量"android:inputType="textPersonName"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toTopOf="parent" /><EditTextandroid:id="@+id/et_path"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_marginStart="8dp"android:layout_marginLeft="8dp"android:layout_marginTop="16dp"android:layout_marginEnd="8dp"android:layout_marginRight="8dp"android:ems="10"android:inputType="textPersonName"android:text="http://192.168.1.130:8080/Day10/QQ.exe"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toBottomOf="@+id/et_threadcount" /><Buttonandroid:id="@+id/bt_self"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_marginStart="16dp"android:layout_marginLeft="16dp"android:layout_marginTop="16dp"android:text="自己的下载方式"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toBottomOf="@+id/et_path" /><Buttonandroid:id="@+id/bt_other"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_marginTop="16dp"android:layout_marginEnd="16dp"android:layout_marginRight="16dp"android:text="第三方的下载方式"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintTop_toBottomOf="@+id/et_path" /><LinearLayoutandroid:id="@+id/ll_container"android:layout_width="match_parent"android:layout_height="wrap_content"android:layout_marginStart="8dp"android:layout_marginLeft="8dp"android:layout_marginTop="100dp"android:layout_marginEnd="8dp"android:layout_marginRight="8dp"android:orientation="vertical"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintHorizontal_bias="0.503"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toBottomOf="@+id/et_path"></LinearLayout>
</android.support.constraint.ConstraintLayout>

5.MultiDownloader\lib\src\main\java\com\glsite\lib\MultiDownloader.java

测试:

package com.glsite.lib;import com.sun.jndi.toolkit.url.UrlUtil;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.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.nio.file.Path;public class MultiDownloader {/*** 总共的线程数*/public static final int TOTAL_THREAD_COUNT = 3;/*** 要下载的文件的链接*/public static String path = "http://localhost:8080/Day10/QQ.exe";/*** 运行状态的线程数*/private static int runningThreadCount = 0;public static void main(String[] args) {try {URL url = new URL(path);HttpURLConnection conn = (HttpURLConnection) url.openConnection();conn.setRequestMethod("GET");int code = conn.getResponseCode();if (code == 200) {int length = conn.getContentLength();System.out.println("file length:" + length);RandomAccessFile raf = new RandomAccessFile(getDownloadFileName(path), "rw");// 创建一个空的文件并且设置它的文件长度等于服务器上的文件长度raf.setLength(length);raf.close();int blockSize = length / TOTAL_THREAD_COUNT;System.out.println("every block size:" + blockSize);runningThreadCount = TOTAL_THREAD_COUNT;for (int threadId = 0; threadId < TOTAL_THREAD_COUNT; threadId++) {int startPosition = threadId * blockSize;int endPosition = (threadId + 1) * blockSize -1;if (threadId == (TOTAL_THREAD_COUNT - 1 )) {endPosition = length - 1;}new DownloadThread(threadId, startPosition, endPosition).start();}} else {System.out.println("download error, code = " + code);}} catch (Exception e) {e.printStackTrace();}}/*** 从网络路径获取文件名** @param path*          网络路径* @return  文件名*/private static String getDownloadFileName(String path) {return path.substring(path.lastIndexOf("/") + 1);}/*** 下载文件的线程*/private static class DownloadThread extends Thread{/*** 线程id*/private int threadId;/*** 当前现成下载的起始位置*/private int startPosition;/*** 当前线程下载的终止位置*/private int endPosition;public DownloadThread(int threadId, int startPosition, int endPosition) {this.threadId = threadId;this.startPosition = startPosition;this.endPosition = endPosition;}@Overridepublic void run() {System.out.println("thread:" + threadId + "begin working");try {File finfo = new File(TOTAL_THREAD_COUNT + getDownloadFileName(path) + threadId + ".txt");if (finfo.exists() && finfo.length() > 0) {FileInputStream fis = new FileInputStream(finfo);BufferedReader br = new BufferedReader(new InputStreamReader(fis));String lastPosition = br.readLine();startPosition = Integer.parseInt(lastPosition);fis.close();}URL url = new URL(path);HttpURLConnection conn = (HttpURLConnection) url.openConnection();conn.setRequestMethod("GET");System.out.println("begin and end:" + threadId + " range of download: " + startPosition + "~~" + endPosition);conn.setRequestProperty("Range", "bytes=" + startPosition + "-" + endPosition);int code = conn.getResponseCode();if (code == 206) {InputStream is = conn.getInputStream();RandomAccessFile raf = new RandomAccessFile(getDownloadFileName(path), "rw");raf.seek(startPosition);int len = 0;byte[] buffer = new byte[1024];int total = 0; // downloaded data of current thread in this times;while ((len = is.read(buffer)) != -1) {raf.write(buffer, 0, len);total += len;RandomAccessFile inforaf = new RandomAccessFile(TOTAL_THREAD_COUNT + getDownloadFileName(path) + threadId + ".txt", "rwd");inforaf.write(String.valueOf(startPosition + total).getBytes());inforaf.close();}is.close();raf.close();System.out.println("thread:" + threadId + " download complete...");} else {System.out.println("request download failed.");}} catch (Exception e) {e.printStackTrace();} finally {synchronized (MultiDownloader.class) {runningThreadCount--;if (runningThreadCount <= 0) {System.out.println("multi thread download complete.");for (int i = 0; i < TOTAL_THREAD_COUNT; i++) {File finfo = new File(TOTAL_THREAD_COUNT + getDownloadFileName(path) + i + ".txt");
//                            System.out.println(finfo.delete());}}}}}}}

6.MainActivity.java

package com.glsite.multidownloader;import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.ProgressBar;
import android.widget.Toast;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;public class MainActivity extends AppCompatActivity implements View.OnClickListener {private EditText mEtPath;private EditText mEtThreadCount;private LinearLayout mLLContainer;private Button mBtSelf;private Button mBtOther;/*** 总共的线程数*/public int totalThreadCount = 3;/*** 要下载的文件的链接*/public String path = "http://192.168.1.130:8080/Day10/QQ.exe";/*** 运行状态的线程数*/private static int runningThreadCount = 0;/*** ProgressBar的集合*/private ArrayList<ProgressBar> mPbs;/*** 当前app的缓存目录*/private String CACHE_DIR;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);// 1.找到控件// 2.在button点击事件当中下载文件// 3.下载的时候要在界面显示下载的进度mEtPath = findViewById(R.id.et_path);mEtThreadCount = findViewById(R.id.et_threadcount);mLLContainer = findViewById(R.id.ll_container);mBtSelf = findViewById(R.id.bt_self);mBtOther = findViewById(R.id.bt_other);mBtSelf.setOnClickListener(this);mBtOther.setOnClickListener(this);// 初始化缓存目录路径CACHE_DIR = this.getCacheDir().getAbsolutePath() + "/";}@Overridepublic void onClick(View v) {switch (v.getId()) {case R.id.bt_self:downloadBySelf();break;case R.id.bt_other:break;}}/*** 通过自己自定义的多线程代码去下载网络文件*/private void downloadBySelf() {path =  mEtPath.getText().toString().trim();totalThreadCount = Integer.valueOf(mEtThreadCount.getText().toString().trim());mLLContainer.removeAllViews();mPbs = new ArrayList<>();for (int i = 0; i < totalThreadCount; i++) {// 有几个线程就添加几个progressbarProgressBar pb = (ProgressBar) View.inflate(this, R.layout.pb, null);mLLContainer.addView(pb);mPbs.add(pb);}new Thread() {@Overridepublic void run() {try {URL url = new URL(path);HttpURLConnection conn = (HttpURLConnection) url.openConnection();conn.setRequestMethod("GET");int code = conn.getResponseCode();if (code == 200) {int length = conn.getContentLength();System.out.println("file length:" + length);RandomAccessFile raf = new RandomAccessFile(CACHE_DIR + getDownloadFileName(path), "rw");// 创建一个空的文件并且设置它的文件长度等于服务器上的文件长度raf.setLength(length);raf.close();int blockSize = length / totalThreadCount;System.out.println("every block size:" + blockSize);runningThreadCount = totalThreadCount;for (int threadId = 0; threadId < totalThreadCount; threadId++) {int startPosition = threadId * blockSize;int endPosition = (threadId + 1) * blockSize -1;if (threadId == (totalThreadCount - 1 )) {endPosition = length - 1;}new DownloadThread(threadId, startPosition, endPosition).start();}} else {System.out.println("download error, code = " + code);}} catch (Exception e) {e.printStackTrace();}}}.start();}/*** 从网络路径获取文件名** @param path*          网络路径* @return  文件名*/private static String getDownloadFileName(String path) {return path.substring(path.lastIndexOf("/") + 1);}/*** 下载文件的线程*/private class DownloadThread extends Thread{/*** 线程id*/private int threadId;/*** 当前现成下载的起始位置*/private int startPosition;/*** 当前线程下载的终止位置*/private int endPosition;/*** 当前线程需要去下载的总共的字节*/private int threadTotal;/*** 该线程上一次下载了的字节数*/private int lastDownloadTotalSize;public DownloadThread(int threadId, int startPosition, int endPosition) {this.threadId = threadId;this.startPosition = startPosition;this.endPosition = endPosition;this.threadTotal = endPosition - startPosition;mPbs.get(threadId).setMax(threadTotal);}@Overridepublic void run() {System.out.println("thread:" + threadId + "begin working");try {File finfo = new File(CACHE_DIR + totalThreadCount + getDownloadFileName(path) + threadId + ".txt");if (finfo.exists() && finfo.length() > 0) {FileInputStream fis = new FileInputStream(finfo);BufferedReader br = new BufferedReader(new InputStreamReader(fis));String lastPosition = br.readLine();// 这里计算出来的就是表示的上次该线程下载了多少个字节总数lastDownloadTotalSize = Integer.parseInt(lastPosition) - startPosition;startPosition = Integer.parseInt(lastPosition);fis.close();}URL url = new URL(path);HttpURLConnection conn = (HttpURLConnection) url.openConnection();conn.setRequestMethod("GET");System.out.println("begin and end:" + threadId + " range of download: " + startPosition + "~~" + endPosition);conn.setRequestProperty("Range", "bytes=" + startPosition + "-" + endPosition);int code = conn.getResponseCode();if (code == 206) {InputStream is = conn.getInputStream();RandomAccessFile raf = new RandomAccessFile(CACHE_DIR + getDownloadFileName(path), "rw");raf.seek(startPosition);int len = 0;byte[] buffer = new byte[1024];int total = 0; // downloaded data of current thread in this times;while ((len = is.read(buffer)) != -1) {raf.write(buffer, 0, len);total += len;RandomAccessFile inforaf = new RandomAccessFile(CACHE_DIR + totalThreadCount + getDownloadFileName(path) + threadId + ".txt", "rwd");inforaf.write(String.valueOf(startPosition + total).getBytes());inforaf.close();mPbs.get(threadId).setProgress(total + lastDownloadTotalSize);}is.close();raf.close();System.out.println("thread:" + threadId + " download complete...");} else {System.out.println("request download failed.");}} catch (Exception e) {e.printStackTrace();} finally {synchronized (MainActivity.class) {runningThreadCount--;if (runningThreadCount <= 0) {System.out.println("multi thread download complete.");for (int i = 0; i < totalThreadCount; i++) {File finfo = new File(CACHE_DIR + totalThreadCount + getDownloadFileName(path) + i + ".txt");// System.out.println(finfo.delete());}}}}}}
}

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