java实现适用于安卓的文件下载线程类

2019-12-28 14:52hebedich JAVA教程

本文给大家分享的是java实现适用于安卓的文件下载线程类的代码，有需要的小伙伴可以参考下

代码非常简单实用，这里就不多废话了，直接奉上源码

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									package android.mooc.tools;

									import java.io.BufferedInputStream;

									import java.io.File;

									import java.io.RandomAccessFile;

									import java.net.URL;

									import java.net.URLConnection;

									import android.util.Log;

									public class FileDownloadThread extends Thread {

									  private static final int BUFFER_SIZE = 1024;

									  private URL url;

									  private File file;

									  private int startPosition;

									  private int endPosition;

									  private int curPosition;

									  // 用于标识当前线程是否下载完成

									  private boolean finished = false;

									  private int downloadSize;

									  private boolean state;

									  boolean destory;

									  public boolean isDestory() {

									    return destory;

									  }

									  public void setDestory(boolean destory) {

									    this.destory = destory;

									  }

									  public FileDownloadThread(URL url, File file, int startPosition, int endPosition) {

									    this.url = url;

									    this.file = file;

									    this.startPosition = startPosition;

									    this.curPosition = startPosition;

									    this.endPosition = endPosition;

									    this.downloadSize = 0;

									  }

									  @Override

									  public void run() {

									    destory = false;

									    state = true;

									    BufferedInputStream bis = null;

									    RandomAccessFile fos = null;

									    byte[] buf = new byte[BUFFER_SIZE];

									    URLConnection con = null;

									    try {

									      con = url.openConnection();

									      con.setAllowUserInteraction(true);

									      // 设置当前线程下载的起点，终点

									      con.setRequestProperty("Range", "bytes=" + startPosition + "-" + endPosition);

									      con.setRequestProperty("accept", "*/*");

									      con.setRequestProperty("connection", "Keep-Alive");

									      con.setRequestProperty("Accept-Language", "zh-CN");

									      con.setRequestProperty("Charset", "UTF-8");

									      con.setRequestProperty("User-Agent",

									          "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.2; Trident/4.0; .NET CLR 1.1.4322;"

									              + " .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)");

									      // 使用java中的RandomAccessFile 对文件进行随机读写操作

									      fos = new RandomAccessFile(file, "rw");

									      // 设置开始写文件的位置

									      fos.seek(startPosition);

									      bis = new BufferedInputStream(con.getInputStream());

									      // 开始循环以流的形式读写文件

									      while ((curPosition < endPosition) && (!destory)) {

									        while (state == false) {

									          sleep(2000);

									        }

									        int len = bis.read(buf, 0, BUFFER_SIZE);

									        if (len != -1) {

									          fos.write(buf, 0, len);

									          curPosition = curPosition + len;

									          if (curPosition > endPosition) {

									            downloadSize += len - (curPosition - endPosition);

									          } else {

									            downloadSize += len;

									          }

									        }

									        Log.i("333", "run" + " len=" + len);

									      }

									      // 下载完成设为true

									      this.finished = true;

									      bis.close();

									      fos.close();

									    } catch (Exception e) {

									      e.printStackTrace();

									    }

									  }

									  public boolean isState() {

									    return state;

									  }

									  public void setState(boolean state) {

									    this.state = state;

									  }

									  public boolean isFinished() {

									    return finished;

									  }

									  public int getDownloadSize() {

									    return downloadSize;

									  }

									  public void setDownloadSize(int downloadSize) {

									    this.downloadSize = downloadSize;

									  }

									}