如何加快 Java/Android 中的解压缩时间?

2022-01-15 00:00:00 unzip android android-emulator java zipinputstream

在 android 上解压缩文件似乎非常慢.起初我以为这只是模拟器，但在手机上似乎是一样的.我尝试了不同的压缩级别，最终下降到存储模式，但仍然需要很长时间.

Unzipping files on android seems to be dreadfully slow. At first I thought this was just the emulator but it appears to be the same on the phone. I've tried different compression levels, and eventually dropped down to storage mode but it still takes ages.

总之，一定是有原因的！还有其他人有这个问题吗?我的解压方法是这样的:

Anyway, there must be a reason! Does anyone else have this problem? My unzip method looks like this:

public void unzip()
{
try{
        FileInputStream fin = new FileInputStream(zipFile);
        ZipInputStream zin = new ZipInputStream(fin);
        File rootfolder = new File(directory);
        rootfolder.mkdirs();
        ZipEntry ze = null;
        while ((ze = zin.getNextEntry())!=null){

            if(ze.isDirectory()){
                dirChecker(ze.getName());
            }
            else{
                FileOutputStream fout = new FileOutputStream(directory+ze.getName());

            for(int c = zin.read();c!=-1;c=zin.read()){
                fout.write(c);
            }
                //Debug.out("Closing streams");
                zin.closeEntry();
                fout.close();

        }
    }
    zin.close();
}
catch(Exception e){
            //Debug.out("Error trying to unzip file " + zipFile);

}
    }

推荐答案

我不知道在 Android 上解压缩是否很慢，但是在循环中逐字节复制肯定会更慢.尝试使用 BufferedInputStream 和 BufferedOutputStream - 它可能会更复杂一些，但根据我的经验，这最终是值得的.

I don't know if unzipping on Android is slow, but copying byte for byte in a loop is surely slowing it down even more. Try using BufferedInputStream and BufferedOutputStream - it might be a bit more complicated, but in my experience it is worth it in the end.

BufferedInputStream in = new BufferedInputStream(zin);
BufferedOutputStream out = new BufferedOutputStream(fout);

然后你可以这样写:

byte b[] = new byte[1024];
int n;
while ((n = in.read(b,0,1024)) >= 0) {
  out.write(b,0,n);
}

相关文章