//流只能读取一遍，以下方法可以实现流的复用
List<InputStream> list = Lists.newArrayList();
try {
ByteArrayOutputStream out = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int len;
while ((len = inputStream.read(buffer)) > -1 ) {
out.write(buffer, 0, len);
}
out.flush();
out.close();
inputStream.close();
byte[] byteArray = out.toByteArray();
for(int i = 0 ; i < copySum ; i++){
list.add(new ByteArrayInputStream(byteArray));
}
} catch (Exception e) {
return null;
}
return list;
}
大文件流可以参考下面连接（未测试，也未使用，只是看了一遍怎么实现。） 地址：www.cnblogs.com/amosli/p/38… 代码如下:
package com.amos.tool;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.net.HttpURLConnection;
import java.net.URL;
/**
* Created by amosli on 14-7-2.
*/public class DownUtil
{
// 定义下载资源的路径
private String path;
// 指定所下载的文件的保存位置
private String targetFile;
// 定义需要使用多少线程下载资源
private int threadNum;
// 定义下载的线程对象
private DownThread[] threads;
// 定义下载的文件的总大小
private int fileSize;
public DownUtil(String path, String targetFile, int threadNum)
{
this.path = path;
this.threadNum = threadNum;
// 初始化threads数组
threads = new DownThread[threadNum];
this.targetFile = targetFile;
}
public void download() throws Exception
{
URL url = new URL(path);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(5 * 1000);
conn.setRequestMethod("GET");
conn.setRequestProperty(
"Accept",
"image/gif, image/jpeg, image/pjpeg, image/pjpeg, "
+ "application/x-shockwave-flash, application/xaml+xml, "
+ "application/vnd.ms-xpsdocument, application/x-ms-xbap, "
+ "application/x-ms-application, application/vnd.ms-excel, "
+ "application/vnd.ms-powerpoint, application/msword, */*");
conn.setRequestProperty("Accept-Language", "zh-CN");
conn.setRequestProperty("Charset", "UTF-8");
conn.setRequestProperty("Connection", "Keep-Alive");
// 得到文件大小
fileSize = conn.getContentLength();
conn.disconnect();
int currentPartSize = fileSize / threadNum + 1;//这里不必一定要加1,不加1也可以
RandomAccessFile file = new RandomAccessFile(targetFile, "rw");
// 设置本地文件的大小
file.setLength(fileSize);
file.close();
for (int i = 0; i < threadNum; i++)
{
// 计算每条线程的下载的开始位置
int startPos = i * currentPartSize;
// 每个线程使用一个RandomAccessFile进行下载
RandomAccessFile currentPart = new RandomAccessFile(targetFile, "rw");
// 定位该线程的下载位置
currentPart.seek(startPos);
// 创建下载线程
threads[i] = new DownThread(startPos, currentPartSize, currentPart);
// 启动下载线程
threads[i].start();
}
}
// 获取下载的完成百分比
public double getCompleteRate()
{
// 统计多条线程已经下载的总大小
int sumSize = 0;
for (int i = 0; i < threadNum; i++)
{
sumSize += threads[i].length;
}
// 返回已经完成的百分比
return sumSize * 1.0 / fileSize;
}
private class DownThread extends Thread
{
// 当前线程的下载位置
private int startPos;
// 定义当前线程负责下载的文件大小
private int currentPartSize;
// 当前线程需要下载的文件块
private RandomAccessFile currentPart;
// 定义已经该线程已下载的字节数
public int length;
public DownThread(int startPos, int currentPartSize,RandomAccessFile currentPart)
{
this.startPos = startPos;
this.currentPartSize = currentPartSize;
this.currentPart = currentPart;
}
@Override
public void run()
{
try
{
URL url = new URL(path);
HttpURLConnection conn = (HttpURLConnection)url.openConnection();
conn.setConnectTimeout(5 * 1000);
conn.setRequestMethod("GET");
conn.setRequestProperty(
"Accept",
"image/gif, image/jpeg, image/pjpeg, image/pjpeg, "
+ "application/x-shockwave-flash, application/xaml+xml, "
+ "application/vnd.ms-xpsdocument, application/x-ms-xbap, "
+ "application/x-ms-application, application/vnd.ms-excel, "
+ "application/vnd.ms-powerpoint, application/msword, */*");
conn.setRequestProperty("Accept-Language", "zh-CN");
conn.setRequestProperty("Charset", "UTF-8");
InputStream inStream = conn.getInputStream();
// 跳过startPos个字节，表明该线程只下载自己负责哪部分文件。
inStream.skip(this.startPos);
byte[] buffer = new byte[1024];
int hasRead = 0;
// 读取网络数据，并写入本地文件
while (length < currentPartSize
&& (hasRead = inStream.read(buffer)) != -1)
{
currentPart.write(buffer, 0, hasRead);
// 累计该线程下载的总大小
length += hasRead;
}
currentPart.close();
inStream.close();
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
}
main:
import com.amos.tool.DownUtil;
import org.omg.PortableServer.THREAD_POLICY_ID;
/**
* Created by amosli on 14-7-2.
*/
public class DownUtilTest {
public static void main(String args[]) throws Exception {
final DownUtil downUtil = new DownUtil("http://mirrors.cnnic.cn/apache/tomcat/tomcat-7/v7.0.54/bin/apache-tomcat-7.0.54.zip", "tomcat-7.0.54.zip", 3);
downUtil.download();
new Thread(new Runnable() {
@Override
public void run() {
while(downUtil.getCompleteRate()<1){
System.out.println("已完成:"+downUtil.getCompleteRate());
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}).start();
}
}
