文件io Java:解压比压缩慢得多
我有一些代码,可以将一个文件通过网络发送,然后在另一端解压。我还在测试代码,源代码和目标代码是一样的。压缩文件需要一分钟的时间。解压文件需要一个小时。我觉得我的代码中一定有缺陷,才会有这么大的差异。以下是要解压缩的代码:
public String uncompressLocalZip(String filename,String strUUID,ParentEntry pe,boolean bControlFileProgress) {
final int BUFFER = 2048;
BufferedOutputStream out = null;
ZipInputStream zis = null;
try {
FileInputStream fis = new FileInputStream(Constants.conf.getFileDirectory() + Constants.PATH_SEPARATOR + strUUID + Constants.PATH_SEPARATOR + filename);
zis = new ZipInputStream(new BufferedInputStream(fis));
ZipEntry entry;
long totallength = 0;
long size = 0;
if (pe !=null)
size = pe.getSize();
while((entry = zis.getNextEntry()) != null) {
System.out.println("Extracting: " +entry);
int count;
byte data[] = new byte[BUFFER];
// write the files to the disk
File fileOutput = new File(Constants.conf.getFileDirectory() + Constants.PATH_SEPARATOR + strUUID + Constants.PATH_SEPARATOR + Constants.conf.getUncompressFolderName() + Constants.PATH_SEPARATOR + entry.getName());
new File(fileOutput.getParent()).mkdirs();
BufferedOutputStream fos = new BufferedOutputStream(new FileOutputStream(fileOutput));
out = new BufferedOutputStream(fos, BUFFER);
while ((count = zis.read(data, 0, BUFFER)) != -1) {
out.write(data, 0, count);
totallength += count;
}
out.flush();
}
}
catch(Exception e) {
e.printStackTrace();
return("FAILED");
}
finally {
try {if ( out!= null) out.close();} catch (IOException ioe) {}
try {if ( zis!= null) zis.close();} catch (IOException ioe) {}
}
return("SUCCESS");
}
以下是邮政编码:
public void createLocalZip(String filename,ProcessEntry pe) {
ZipOutputStream out=null;
try {
File fileOutput = new File (filename);
out = new ZipOutputStream(new BufferedOutputStream(new FileOutputStream(fileOutput)));
long totallength=0;
long size = pe.getParentEntry().getSize();
String strStartDirectory;
if (pe.getParentEntry().isDirectory())
strStartDirectory=pe.getParentEntry().getUrl();
else
strStartDirectory=pe.getParentEntry().getFolder();
for (int i=0;i<pe.getParentEntry().tableModel3.getRowCount();i++) {
FileEntry fe = pe.getParentEntry().tableModel3.getFileEntry(i);
File fileInput = new File (fe.getUrl());
FileInputStream input = new FileInputStream(fileInput);
BufferedInputStream in = new BufferedInputStream(input);
String strRelativeDir = fe.getUrl().substring(strStartDirectory.length()+1,fe.getUrl().length());
ZipEntry entry = new ZipEntry(strRelativeDir);
out.putNextEntry(entry);
byte[] bbuf = new byte[2048];
int length=0;
while ((in != null) && ((length = in.read(bbuf)) != -1)) {
out.write(bbuf,0,length);
totallength += length;
pe.setProgress((int) (totallength*100/size));
}
in.close();
}
}
catch (Exception e) {
System.out.println(e.getMessage());
}
finally {
try {if (out!=null) out.close();} catch(IOException ioe){}
}
}
更新:此特定测试的压缩比约为90%(1.2GB降至约100MB)。所以我想这可能是额外的磁盘写入,用于解压和压缩,尽管我预计会接近10倍于60倍
共 (0) 个答案