如何在Android中以编程方式解压缩文件？

Question

我需要一个小代码片段,它从给定的.zip文件中解压缩一些文件,并根据它们在压缩文件中的格式提供单独的文件.请发布您的知识并帮助我.

Answer 1

如果Peno的版本有所优化.性能的提高是可感知的.

private boolean unpackZip(String path, String zipname)
{       
     InputStream is;
     ZipInputStream zis;
     try 
     {
         String filename;
         is = new FileInputStream(path + zipname);
         zis = new ZipInputStream(new BufferedInputStream(is));          
         ZipEntry ze;
         byte[] buffer = new byte[1024];
         int count;

         while ((ze = zis.getNextEntry()) != null) 
         {
             filename = ze.getName();

             // Need to create directories if not exists, or
             // it will generate an Exception...
             if (ze.isDirectory()) {
                File fmd = new File(path + filename);
                fmd.mkdirs();
                continue;
             }

             FileOutputStream fout = new FileOutputStream(path + filename);

             while ((count = zis.read(buffer)) != -1) 
             {
                 fout.write(buffer, 0, count);             
             }

             fout.close();               
             zis.closeEntry();
         }

         zis.close();
     } 
     catch(IOException e)
     {
         e.printStackTrace();
         return false;
     }

    return true;
}

Answer 2

基于瓦西里·索辛斯基的答案有点调整和一个小修复:

public static void unzip(File zipFile, File targetDirectory) throws IOException {
    ZipInputStream zis = new ZipInputStream(
            new BufferedInputStream(new FileInputStream(zipFile)));
    try {
        ZipEntry ze;
        int count;
        byte[] buffer = new byte[8192];
        while ((ze = zis.getNextEntry()) != null) {
            File file = new File(targetDirectory, ze.getName());
            File dir = ze.isDirectory() ? file : file.getParentFile();
            if (!dir.isDirectory() && !dir.mkdirs())
                throw new FileNotFoundException("Failed to ensure directory: " +
                        dir.getAbsolutePath());
            if (ze.isDirectory())
                continue;
            FileOutputStream fout = new FileOutputStream(file);
            try {
                while ((count = zis.read(buffer)) != -1)
                    fout.write(buffer, 0, count);
            } finally {
                fout.close();
            }
            /* if time should be restored as well
            long time = ze.getTime();
            if (time > 0)
                file.setLastModified(time);
            */
        }
    } finally {
        zis.close();
    }
}

显着的差异

• public static - 这是一个静态的实用方法,可以在任何地方.
• 2个File参数因为String:/ for files和one 参数之前无法指定zip文件的提取位置.还path + filename连接> /sf/answers/28874681/
• throws- 因为赶上了 - 如果真的对它们不感兴趣的话,添加一个试试.
• 实际上确保所有情况下都存在所需的目录.并非每个zip都包含文件条目之前的所有必需目录条目.这有两个潜在的错误:
  • 如果zip包含一个空目录,而不是生成的目录中有一个现有文件,则会被忽略.返回值mkdirs()很重要.
  • 可能会崩溃不包含目录的zip文件.
• 增加写缓冲区大小,这应该会提高一点性能.存储通常是4k块,以较小的块写入通常比必要的慢.
• 使用魔法finally来防止资源泄漏.

所以

unzip(new File("/sdcard/pictures.zip"), new File("/sdcard"));

应该做相当于原件

unpackZip("/sdcard/", "pictures.zip")

Answer 3

这是我的解压缩方法,我用它:

private boolean unpackZip(String path, String zipname)
{       
     InputStream is;
     ZipInputStream zis;
     try 
     {
         is = new FileInputStream(path + zipname);
         zis = new ZipInputStream(new BufferedInputStream(is));          
         ZipEntry ze;

         while((ze = zis.getNextEntry()) != null) 
         {
             ByteArrayOutputStream baos = new ByteArrayOutputStream();
             byte[] buffer = new byte[1024];
             int count;

             String filename = ze.getName();
             FileOutputStream fout = new FileOutputStream(path + filename);

             // reading and writing
             while((count = zis.read(buffer)) != -1) 
             {
                 baos.write(buffer, 0, count);
                 byte[] bytes = baos.toByteArray();
                 fout.write(bytes);             
                 baos.reset();
             }

             fout.close();               
             zis.closeEntry();
         }

         zis.close();
     } 
     catch(IOException e)
     {
         e.printStackTrace();
         return false;
     }

    return true;
}

Answer 4

Android有内置的Java API.查看java.util.zip包.

ZipInputStream类是你应该研究的.从ZipInputStream中读取ZipEntry并将其转储到filesystem /文件夹中.检查类似的例子压缩成zip文件.

Answer 5

科特林的方式

//FileExt.kt

data class ZipIO (val entry: ZipEntry, val output: File)

fun File.unzip(unzipLocationRoot: File? = null) {

    val rootFolder = unzipLocationRoot ?: File(parentFile.absolutePath + File.separator + nameWithoutExtension)
    if (!rootFolder.exists()) {
       rootFolder.mkdirs()
    }

    ZipFile(this).use { zip ->
        zip
        .entries()
        .asSequence()
        .map {
            val outputFile = File(rootFolder.absolutePath + File.separator + it.name)
            ZipIO(it, outputFile)
        }
        .map {
            it.output.parentFile?.run{
                if (!exists()) mkdirs()
            }
            it
        }
        .filter { !it.entry.isDirectory }
        .forEach { (entry, output) ->
            zip.getInputStream(entry).use { input ->
                output.outputStream().use { output ->
                    input.copyTo(output)
                }
            }
        }
    }

}

用法

val zipFile = File("path_to_your_zip_file")
file.unzip()

Answer 6

虽然已经在这里的答案运作良好,但我发现它们比我希望的稍慢.相反,我使用了zip4j,我认为这是最好的解决方案,因为它的速度.它还允许压缩量的不同选项,我觉得这很有用.

Answer 7

2016年更新使用以下课程

    package com.example.zip;

    import java.io.BufferedOutputStream;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileOutputStream;
    import java.util.zip.ZipEntry;
    import java.util.zip.ZipInputStream;
    import android.util.Log;

    public class DecompressFast {



 private String _zipFile; 
  private String _location; 

  public DecompressFast(String zipFile, String location) { 
    _zipFile = zipFile; 
    _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()); 
         BufferedOutputStream bufout = new BufferedOutputStream(fout);
          byte[] buffer = new byte[1024];
          int read = 0;
          while ((read = zin.read(buffer)) != -1) {
              bufout.write(buffer, 0, read);
          }




          bufout.close();

          zin.closeEntry(); 
          fout.close(); 
        } 

      } 
      zin.close(); 


      Log.d("Unzip", "Unzipping complete. path :  " +_location );
    } catch(Exception e) { 
      Log.e("Decompress", "unzip", e); 

      Log.d("Unzip", "Unzipping failed");
    } 

  } 

  private void _dirChecker(String dir) { 
    File f = new File(_location + dir); 

    if(!f.isDirectory()) { 
      f.mkdirs(); 
    } 
  } 


 }

如何使用

 String zipFile = Environment.getExternalStorageDirectory() + "/the_raven.zip"; //your zip file location
    String unzipLocation = Environment.getExternalStorageDirectory() + "/unzippedtestNew/"; // destination folder location
  DecompressFast df= new DecompressFast(zipFile, unzipLocation);
    df.unzip();

权限

 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
 <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

Answer 8

根据@zapl的回答,解压缩进度报告:

public interface UnzipFile_Progress
{
    void Progress(int percent, String FileName);
}

// unzip(new File("/sdcard/pictures.zip"), new File("/sdcard"));
public static void UnzipFile(File zipFile, File targetDirectory, UnzipFile_Progress progress) throws IOException,
        FileNotFoundException
{
    long total_len = zipFile.length();
    long total_installed_len = 0;

    ZipInputStream zis = new ZipInputStream(new BufferedInputStream(new FileInputStream(zipFile)));
    try
    {
        ZipEntry ze;
        int count;
        byte[] buffer = new byte[1024];
        while ((ze = zis.getNextEntry()) != null)
        {
            if (progress != null)
            {
                total_installed_len += ze.getCompressedSize();
                String file_name = ze.getName();
                int percent = (int)(total_installed_len * 100 / total_len);
                progress.Progress(percent, file_name);
            }

            File file = new File(targetDirectory, ze.getName());
            File dir = ze.isDirectory() ? file : file.getParentFile();
            if (!dir.isDirectory() && !dir.mkdirs())
                throw new FileNotFoundException("Failed to ensure directory: " + dir.getAbsolutePath());
            if (ze.isDirectory())
                continue;
            FileOutputStream fout = new FileOutputStream(file);
            try
            {
                while ((count = zis.read(buffer)) != -1)
                    fout.write(buffer, 0, count);
            } finally
            {
                fout.close();
            }

            // if time should be restored as well
            long time = ze.getTime();
            if (time > 0)
                file.setLastModified(time);
        }
    } finally
    {
        zis.close();
    }
}