package www.zgl.net.down;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
public class StreamTools {
public static byte[] isToData(InputStream is) throws IOException{
ByteArrayOutputStream bops = new ByteArrayOutputStream();
byte buffer[] = new byte[1024];
int len = 0;
while ((len = is.read(buffer)) != -1) {
bops.write(buffer, 0, len);
}
byte data[] = bops.toByteArray();
bops.flush();
bops.close();
is.close();
return data;
}
}
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package www.zgl.net.down;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
public class DownLoadTest {
public File file;
public RandomAccessFile accessFile;
// 线程的数量
int threadNum = 3;
// 每个线程负责下载的大小
int blockSize;
// 创建访问的路径
// public String path = "http://172.22.64.32:8080/doudou/youdao.exe";
public String path = "http://172.22.64.32:8080/doudou/youdao.exe";
public void testDown() {
try {
// 创建出URL对象
URL url = new URL(path);
// 创建出 HttpURLConnection对象
HttpURLConnection httpURLConnection = (HttpURLConnection) url
.openConnection();
// 设置 发请求发送的方式
httpURLConnection.setRequestMethod("GET");
// 设置请求是否超时时间
httpURLConnection.setConnectTimeout(5000);
// 设置
httpURLConnection
.setRequestProperty("User-Agent",
" Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; Trident/6.0)");
// 是否响应成功
if (httpURLConnection.getResponseCode() == 200) {
// 获取文件的大小
int size = httpURLConnection.getContentLength();
System.out.println("文件的大小" + size);
// 创建文件
file = new File("youdao.exe");
accessFile = new RandomAccessFile(file, "rwd");
// 设置文件的大小
accessFile.setLength(size);
// 每个线程下载的大小
blockSize = size / threadNum;
// 开三个线程 操作此文件
for (int i = 1; i <= threadNum; i++) {
// 1 2 3
// 计算出每个线程开始的位置
int startSize = (i - 1) * blockSize;
// 结束位置
int endSize = (i) * blockSize;
// 当线程是最后一个线程的时候
if (i == threadNum) {
// 判断文件的大小是否大于计算出来的结束位置
if (size > endSize) {
// 结束位置 等于 文件的大小
endSize = size;
}
}
// 为每个线程创建一个随机的读取
RandomAccessFile threadAccessFile = new RandomAccessFile(
file, "rwd");
new Thread(new DownLoadThread(threadAccessFile, startSize,
endSize, path)).start();
}
}
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void main(String[] args) {
DownLoadTest downLoadTest = new DownLoadTest();
// 调用下载方法
downLoadTest.testDown();
}
}
class DownLoadThread implements Runnable {
// 下载文件的封装
public RandomAccessFile accessFile;
// 线程下载文件的起始位置
public int startSize;
public int endSize;
// 文件下载的path路径
public String path;
public DownLoadThread(RandomAccessFile accessFile, int startSize,
int endSize, String path) {
this.accessFile = accessFile;
this.startSize = startSize;
this.endSize = endSize;
this.path = path;
}
@Override
public void run() {
// 执行run方法
try {
// 创建URL对象
URL url = new URL(path);
// 创建HttpURLConnection对象
HttpURLConnection httpURLConnection = (HttpURLConnection) url
.openConnection();
// 设置请求的头
httpURLConnection.setRequestMethod("GET");
// 设置请求是否超时时间
httpURLConnection.setConnectTimeout(5000);
// 设置
httpURLConnection
.setRequestProperty("User-Agent",
" Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; Trident/6.0)");
// 关键的设置
httpURLConnection.setRequestProperty("Range", "bytes=" + startSize
+ "-" + endSize);
// 输出当前线程
System.out.println("当前线程" + Thread.currentThread().getName()
+ " 下载开始位置:" + startSize + " 下载结束位置:" + endSize);
// 响应成功
// 设置随机读取文件的 开始位置
accessFile.seek(startSize);
// 获取相应流对象
InputStream is = httpURLConnection.getInputStream();
// 创建输出流对象
byte buffer[] = new byte[1024];
int len = 0;
while ((len = is.read(buffer)) != -1) {
accessFile.write(buffer, 0, len);
}
accessFile.close();
is.close();
System.out.println(Thread.currentThread().getName() + "线程执行完毕");
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}