java.lang.OutOfMemoryError:从URL下载大文件时的Java堆空间 [英] java.lang.OutOfMemoryError: Java heap space while downloading a large file from an URL
问题描述
我想从URL下载文件.文件大小为564.31MB.我不知道这是怎么回事.另外,我想知道我的代码是否是从URL下载文件的正确方法.如果有更好的方法,请详细告诉我为什么它比这个更好.谢谢.
I want to download a file from an URL. The file size is 564.31MB. I have no clue what error is going on here. Also, I'm wondering if my code is the correct way to download a file from an URL. If there is a better way, please tell me in detail why it is better than this. Thanks.
import org.apache.commons.io.FilenameUtils;
import java.io.*;
import java.net.MalformedURLException;
import java.net.URL;
/**
* Created by lukas on 6/30/16.
*/
public class Main {
public static void main(String[] args){
try {
String link = "https://s.basketbuild.com/uploads/devs/dianlujitao/oneplus3/cm13/cm-13.0-20160621-UNOFFICIAL-oneplus3.zip";
URL url = new URL(link);
InputStream inputStream = new BufferedInputStream(url.openStream());
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
int n=0;
byte[] buf = new byte[1024];
long duration = System.currentTimeMillis();
while((n=inputStream.read(buf))!=-1){
byteArrayOutputStream.write(buf, 0, n);
}
duration = System.currentTimeMillis()-duration;
System.out.println("Finish in "+duration+"ms");
inputStream.close();
File dir = new File("Output path");
if(!dir.exists())
dir.mkdirs();
String fileBaseName = FilenameUtils.getBaseName(link);
String fileExtension = FilenameUtils.getExtension(link);
System.out.println("Name: "+fileBaseName+'.'+fileExtension);
File outputFile = new File(dir, fileBaseName+'.'+fileExtension);
if(!outputFile.exists()){
outputFile.createNewFile();
}
FileOutputStream fileOutputStream = new FileOutputStream(outputFile);
fileOutputStream.write(byteArrayOutputStream.toByteArray());
//release outputstream
byteArrayOutputStream.close();
fileOutputStream.close();
System.out.println("Your download has been finished");
} catch (MalformedURLException e) {
e.printStackTrace();
System.out.println("Something unexpected has happened!");
} catch (IOException e) {
e.printStackTrace();
System.out.println("Something unexpected has happened!");
}
}
}
这是我的控制台所说的:
Here is what my console says:
Finish in 133506ms
Name: cm-13.0-20160621-UNOFFICIAL-oneplus3.zip
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
at java.util.Arrays.copyOf(Arrays.java:3236)
at java.io.ByteArrayOutputStream.toByteArray(ByteArrayOutputStream.java:191)
at Main.main(Main.java:42)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
推荐答案
-
ByteArrayOutputStream在堆内存中分配其所有数据.正确的方法是直接写入文件,并为此使用缓冲区,以便优化磁盘I/O:
ByteArrayOutputStream allocates all its data in the heap memory. The correct way is to write directly to the file, and use a buffer for that so disk I/O is optimized:
OutputStream os = new BufferedOutputStream(new FileOutputStream("myFile.txt"));
System.currentTimeMillis()为您提供当前日期和时间,该日期和时间可能随时更改.这并不是要计算持续时间,请使用SystemClock.nanoTime().
System.currentTimeMillis() gives you the current date and time, which may change at any point. It's not meant to calculate durations, use SystemClock.nanoTime() for that.
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