在Android中下载和解压Zip文件
在Android中下载和解压Zip文件
提问于 2012-02-17 14:53:06
我的应用程序正在从服务器下载zip文件并提取此zip文件并将文件保存到SD卡中，但问题是如果我正在下载4-5MB的zip文件并将其解压缩，这工作正常，但如果我正在下载30-35MB的zip文件，这将给我错误，为我糟糕的英语沟通道歉。
以下是我下载和解压Zip文件的代码：
public class UnzipManager {
private static String BASE_FOLDER;
public static Context localContext;
public static String passurl;
public static int count;
public static Context context;
/*
* You can use this flag to check whether Unzippingthread is still running..
*/
public static boolean isDownloadInProgress;
/*
* After unzipping using this flag ,you can check whether any low memory
* exceptions Occurred or not..and alert user accordingly..
*/
public static boolean isLowOnMemory;
public static int i = 0;
public static ZipEntry zipEntry;
public static void startUnzipping(Context ctx, int c, String url) {
context = ctx;
count = c;
/*
* MAKE SURE THAT localContext VARIABLE HAS BEEN INITIALIZED BEFORE
* INVOKING THIS METHOD.
*
* ALSO MAKE SURE YOU HAVE SET "INTERNET" AND "NETWORK ACCESS STATE"
* PERMISSIONS IN APPLICATION'S MANIFEST FILE.
*/
Log.d("DEBUG", "In startUnzipping()");
UnzipManager.BASE_FOLDER = Environment.getExternalStorageDirectory()
+ File.separator + "samples";
/*
*
*/
Log.d("DEBUG", "BASE_FOLDER:" + UnzipManager.BASE_FOLDER);
UnzipManager.isLowOnMemory = false;
// Start unzipping in a thread..which is safer
// way to do high cost processes..
passurl = url;
new UnzipThread().start();
}
private static class UnzipThread extends Thread {
@Override
public void run() {
UnzipManager.isDownloadInProgress = true;
Log.d("DEBUG", "Unzipping----------------------------");
URLConnection urlConnection;
try {
/************************************************
*
* IF you are unzipping a zipped file save under some URL in
* remote server
* **********************************************/
URL finalUrl = new URL(passurl
/* Url string where the zipped file is stored... */);
urlConnection = finalUrl.openConnection();
// Get the size of the ( zipped file's) inputstream from
// server..
int contentLength = urlConnection.getContentLength();
Log.d("DEBUG", "urlConnection.getContentLength():"
+ contentLength);
/*****************************************************
*
* YOU CAN GET INPUT STREAM OF A ZIPPED FILE FROM ASSETS FOLDER
* AS WELL..,IN THAT CASE JUST PASS THAT INPUTSTEAM OVER
* HERE...MAKE SURE YOU HAVE SET STREAM CONTENT LENGTH OF THE
* SAME..
*
******************************************************/
ZipInputStream zipInputStream = new ZipInputStream(
urlConnection.getInputStream());
/*
* Iterate over all the files and folders
*/
for (zipEntry = zipInputStream.getNextEntry(); zipEntry != null; zipEntry = zipInputStream
.getNextEntry()) {
Log.d("DEBUG", "Extracting: " + zipEntry.getName() + "...");
/*
* Extracted file will be saved with same file name that in
* zipped folder.
*/
String innerFileName = BASE_FOLDER + File.separator
+ zipEntry.getName();
File innerFile = new File(innerFileName);
/*
* Checking for pre-existence of the file and taking
* necessary actions
*/
if (innerFile.exists()) {
Log.d("DEBUG",
"The Entry already exits!, so deleting..");
innerFile.delete();
}
/*
* Checking for extracted entry for folder type..and taking
* necessary actions
*/
if (zipEntry.isDirectory()) {
Log.d("DEBUG", "The Entry is a directory..");
innerFile.mkdirs();
} else {
Log.d("DEBUG", "The Entry is a file..");
FileOutputStream outputStream = new FileOutputStream(
innerFileName);
final int BUFFER_SIZE = 2048;
/*
* Get the buffered output stream..
*/
BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(
outputStream, BUFFER_SIZE);
/*
* Write into the file's buffered output stream ,..
*/
int count = 0;
byte[] buffer = new byte[BUFFER_SIZE];
while ((count = zipInputStream.read(buffer, 0,
BUFFER_SIZE)) != -1) {
bufferedOutputStream.write(buffer, 0, count);
}
/***********************************************
* IF YOU WANT TO TRACK NO OF FILES DOWNLOADED, HAVE A
* STATIC COUNTER VARIABLE, INITIALIZE IT IN
* startUnzipping() before calling startUnZipping(), AND
* INCREMENT THE COUNTER VARIABLE OVER HERE..LATER YOU
* CAN USE VALUE OF COUNTER VARIABLE TO CROSS VERIFY
* WHETHER ALL ZIPPED FILES PROPERLY UNZIPPED AND SAVED
* OR NOT.
*
* ************************************************
*/
/*
* Handle closing of output streams..
*/
bufferedOutputStream.flush();
bufferedOutputStream.close();
}
/*
* Finish the current zipEntry
*/
zipInputStream.closeEntry();
}
/*
* Handle closing of input stream...
*/
zipInputStream.close();
Log.d("DEBUG", "--------------------------------");
Log.d("DEBUG", "Unzipping completed..");
i = 1;
} catch (IOException e) {
Log.d("DEBUG", "Exception occured: " + e.getMessage());
if (e.getMessage().equalsIgnoreCase("No space left on device")) {
UnzipManager.isLowOnMemory = true;
}
e.printStackTrace();
}
MainActivity.pd.dismiss();
((MainActivity)context).finish();
UnzipManager.isDownloadInProgress = false;
}
};
}Logcat错误为：-
02-17 12:21:16.835: D/DEBUG(20562): Exception occured: /mnt/sdcard/samples/iPhone_zendura_Q4a/0.png (No such file or directory)
02-17 12:21:16.835: W/System.err(20562): java.io.FileNotFoundException: /mnt/sdcard/samples/iPhone_zendura_Q4a/0.png (No such file or directory)
02-17 12:21:16.906: W/System.err(20562): at org.apache.harmony.luni.platform.OSFileSystem.open(Native Method)
02-17 12:21:16.906: W/System.err(20562): at dalvik.system.BlockGuard$WrappedFileSystem.open(BlockGuard.java:232)
02-17 12:21:16.906: W/System.err(20562): at java.io.FileOutputStream.<init>(FileOutputStream.java:94)
02-17 12:21:16.906: W/System.err(20562): at java.io.FileOutputStream.<init>(FileOutputStream.java:165)
02-17 12:21:16.906: W/System.err(20562): at java.io.FileOutputStream.<init>(FileOutputStream.java:144)
02-17 12:21:16.906: W/System.err(20562): at com.android.screens.UnzipManager$UnzipThread.run(UnzipManager.java:129)回答 3
Stack Overflow用户
发布于 2012-02-17 18:14:52
正如JoxTraex所说:错误真的很明显。
在UnzipManager的129行，您试图打开一个不存在的文件。这就是为什么你会得到一个FileNotFoundException。您应该检查您的压缩文件，如果它是一个正确的文件，并可以在您的PC上正确解压。
也试着调试一下。在该行上添加一个断点，让应用程序调试并观察当特定文件位置出现时会发生什么。
Stack Overflow用户
发布于 2013-01-31 06:12:41
如果文件存在，不要删除(因为文件将被覆盖)或再次实例化innerFile。
if (innerFile.exists()) {
Log.d("DEBUG",
"The Entry already exits!, so deleting..");
innerFile.delete();
}
//Instantiate Again
innerFile = new File(innerFileName);删除innerFile会丢失文件，并且在尝试使用innerFile创建目录时会导致FileNotFoundException。
Stack Overflow用户
发布于 2015-06-03 04:27:29
这是使用performance improvement answer的最终代码，它在1分钟内将一个23 MB的文件解压缩到一个130 MB的文件夹中：
public class Decompress {
private String _zipFile;
private String _location;
public Decompress(String zipFile, String location) {
_zipFile = zipFile;
_location = location;
_dirChecker("");
}
public void unzip() {
try {
FileInputStream fin = new FileInputStream(_zipFile);
ZipInputStream zin = new ZipInputStream(fin);
byte b[] = new byte[1024];
ZipEntry ze = null;
while ((ze = zin.getNextEntry()) != null) {
Log.v("Decompress", "Unzipping " + ze.getName());
if(ze.isDirectory()) {
_dirChecker(ze.getName());
} else {
FileOutputStream fout = new FileOutputStream(_location + ze.getName());
BufferedInputStream in = new BufferedInputStream(zin);
BufferedOutputStream out = new BufferedOutputStream(fout);
int n;
while ((n = in.read(b,0,1024)) >= 0) {
out.write(b,0,n);
}
zin.closeEntry();
out.close();
}
}
zin.close();
} catch(Exception e) {
Log.e("Decompress", "unzip", e);
}
}
private void _dirChecker(String dir) {
File f = new File(_location + dir);
if(!f.isDirectory()) {
f.mkdirs();
}
}}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/9324103
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