我正在下载一个zip文件夹并保存在我的Android设备的特定文件夹中。我的应用程序没有访问该文件夹，因为它是压缩的。我想从服务器下载后解压缩文件夹并保存在特定的文件夹中。
我的代码在这里：
public void DownloadDatabase(String DownloadUrl, String fileName) {
try {
File root = android.os.Environment.getExternalStorageDirectory();
File dir = new File(root.getAbsolutePath() + "/timy/databases");
if(dir.exists() == false){
dir.mkdirs();
}
URL url = new URL("http://myexample.com/android/timy.zip");
File file = new File(dir,fileName);
long startTime = System.currentTimeMillis();
Log.d("DownloadManager" , "download url:" +url);
Log.d("DownloadManager" , "download file name:" + fileName);
URLConnection uconn = url.openConnection();
uconn.setConnectTimeout(TIMEOUT_SOCKET);
InputStream is = uconn.getInputStream();
ZipInputStream zipinstream = new ZipInputStream(new BufferedInputStream(is));
ZipEntry zipEntry;
while((zipEntry = zipinstream.getNextEntry()) != null){
String zipEntryName = zipEntry.getName();
File file1 = new File(file + zipEntryName);
if(file1.exists()){
}else{
if(zipEntry.isDirectory()){
file1.mkdirs();
}
}
}
BufferedInputStream bufferinstream = new BufferedInputStream(is);
ByteArrayBuffer baf = new ByteArrayBuffer(5000);
int current = 0;
while((current = bufferinstream.read()) != -1){
baf.append((byte) current);
}
FileOutputStream fos = new FileOutputStream( file);
fos.write(baf.toByteArray());
fos.flush();
fos.close();
Log.d("DownloadManager" , "download ready in" + ((System.currentTimeMillis() - startTime)/1000) + "sec");
}
catch(IOException e) {
Log.d("DownloadManager" , "Error:" + e);
e.printStackTrace();
}
}
我的logcat显示错误。只是文件夹在我的设备中创建，没有文件下载解压缩。不使用inputZipStream方法，我的压缩文件夹正在下载并保存在SD卡中。当我想解压缩它时，它就不会发生了。
答案 0 :(得分：21)
本文是关于如何编写实用程序类，使用内置Java API在压缩zip存档中提取文件和目录。
java.util.zip包提供以下类，用于从ZIP存档中提取文件和目录：
ZipInputStream：这是主类，可用于读取zip文件并提取存档中的文件和目录（条目）。以下是本课程的一些重要用法： - 通过其构造函数ZipInputStream（FileInputStream）读取一个zip 通过方法getNextEntry（）读取文件和目录的条目 通过方法读取（字节）读取当前条目的二进制数据 - 通过方法closeEntry（）关闭当前条目 - 通过方法close（）
关闭zip文件ZipEntry：此类表示zip文件中的条目。每个文件或目录都表示为ZipEntry对象。它的方法getName（）返回一个String，它表示文件/目录的路径。路径采用以下形式： FOLDER_1 / subfolder_1 / subfolder_2 / ... / subfolder_n / file.ext
基于ZipEntry的路径，我们在解压缩zip文件时重新创建目录结构。
下面的类用于解压缩下载zip并提取文件并存储您想要的位置。
public class UnzipUtil
{
private String zipFile;
private String location;
public UnzipUtil(String zipFile, String location)
{
this.zipFile = zipFile;
this.location = location;
dirChecker("");
}
public void unzip()
{
try
{
FileInputStream fin = new FileInputStream(zipFile);
ZipInputStream zin = new ZipInputStream(fin);
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());
byte[] buffer = new byte[8192];
int len;
while ((len = zin.read(buffer)) != -1)
{
fout.write(buffer, 0, len);
}
fout.close();
zin.closeEntry();
}
}
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();
}
}
}
MainActivity.Class：
public class MainActivity extends Activity
{
private ProgressDialog mProgressDialog;
String Url="http://hasmukh/hb.zip";
String unzipLocation = Environment.getExternalStorageDirectory() + "/unzipFolder/";
String StorezipFileLocation =Environment.getExternalStorageDirectory() + "/DownloadedZip";
String DirectoryName=Environment.getExternalStorageDirectory() + "/unzipFolder/files/";
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
DownloadZipfile mew = new DownloadZipfile();
mew.execute(url);
}
//-This is method is used for Download Zip file from server and store in Desire location.
class DownloadZipfile extends AsyncTask<String, String, String>
{
String result ="";
@Override
protected void onPreExecute()
{
super.onPreExecute();
mProgressDialog = new ProgressDialog(MainActivity.this);
mProgressDialog.setMessage("Downloading...");
mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
mProgressDialog.setCancelable(false);
mProgressDialog.show();
}
@Override
protected String doInBackground(String... aurl)
{
int count;
try
{
URL url = new URL(aurl[0]);
URLConnection conexion = url.openConnection();
conexion.connect();
int lenghtOfFile = conexion.getContentLength();
InputStream input = new BufferedInputStream(url.openStream());
OutputStream output = new FileOutputStream(StorezipFileLocation);
byte data[] = new byte[1024];
long total = 0;
while ((count = input.read(data)) != -1)
{
total += count;
publishProgress(""+(int)((total*100)/lenghtOfFile));
output.write(data, 0, count);
}
output.close();
input.close();
result = "true";
} catch (Exception e) {
result = "false";
}
return null;
}
protected void onProgressUpdate(String... progress)
{
Log.d("ANDRO_ASYNC",progress[0]);
mProgressDialog.setProgress(Integer.parseInt(progress[0]));
}
@Override
protected void onPostExecute(String unused)
{
mProgressDialog.dismiss();
if(result.equalsIgnoreCase("true"))
{
try
{
unzip();
} catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
else
{
}
}
}
//This is the method for unzip file which is store your location. And unzip folder will store as per your desire location.
public void unzip() throws IOException
{
mProgressDialog = new ProgressDialog(MainActivity.this);
mProgressDialog.setMessage("Please Wait...");
mProgressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
mProgressDialog.setCancelable(false);
mProgressDialog.show();
new UnZipTask().execute(StorezipFileLocation, DirectoryName);
}
private class UnZipTask extends AsyncTask<String, Void, Boolean>
{
@SuppressWarnings("rawtypes")
@Override
protected Boolean doInBackground(String... params)
{
String filePath = params[0];
String destinationPath = params[1];
File archive = new File(filePath);
try
{
ZipFile zipfile = new ZipFile(archive);
for (Enumeration e = zipfile.entries(); e.hasMoreElements();)
{
ZipEntry entry = (ZipEntry) e.nextElement();
unzipEntry(zipfile, entry, destinationPath);
}
UnzipUtil d = new UnzipUtil(StorezipFileLocation, DirectoryName);
d.unzip();
}
catch (Exception e)
{
return false;
}
return true;
}
@Override
protected void onPostExecute(Boolean result)
{
mProgressDialog.dismiss();
}
private void unzipEntry(ZipFile zipfile, ZipEntry entry,String outputDir) throws IOException
{
if (entry.isDirectory())
{
createDir(new File(outputDir, entry.getName()));
return;
}
File outputFile = new File(outputDir, entry.getName());
if (!outputFile.getParentFile().exists())
{
createDir(outputFile.getParentFile());
}
// Log.v("", "Extracting: " + entry);
BufferedInputStream inputStream = new BufferedInputStream(zipfile.getInputStream(entry));
BufferedOutputStream outputStream = new BufferedOutputStream(new FileOutputStream(outputFile));
try
{
}
finally
{
outputStream.flush();
outputStream.close();
inputStream.close();
}
}
private void createDir(File dir)
{
if (dir.exists())
{
return;
}
if (!dir.mkdirs())
{
throw new RuntimeException("Can not create dir " + dir);
}
}}
}
Note: Do not forgot to add below permission in android Manifest.xml file.
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" ></uses-permission>
<uses-permission android:name="android.permission.INTERNET" />
答案 1 :(得分：1)
解压缩功能
ZipManager zipManager = new ZipManager();
zipManager.unzip(inputPath + inputFile, outputPath);
<强>初始化
filter答案 2 :(得分：0)
对于android，有一个第三方库可供免费使用。
该库将自动下载文件并自动提取到您想要的位置。
您可以在这里查看此库。
ExtractionLib for Android