Android压缩文件访问总结

た入场券 2022-06-18 00:59 131阅读 0赞

## Android压缩文件访问总结 ##

Android压缩文件也是可以通过代码来访问到的，这里使用到两个Zip压缩类，并且只能读取到Zip类型的压缩文件。也可以对文件进行解压，其实就是读取后再写出来。  
直接提供代码，都是基于java中IO流的知识了：

# 一．获取压缩文件内的文件名称 #

//扫描压缩文件里面的文件名字，传人的是压缩文件的决定路径
        public static void scanZipFile(String zipname) {
            try {
                ZipInputStream zin = new ZipInputStream(
                        new FileInputStream(zipname));
                ZipEntry entry;
                while ((entry = zin.getNextEntry()) != null) {
                    //压缩文件里面的文件名称
                    System.out.println(entry.getName());
                    zin.closeEntry();
                }
                zin.close();
            } catch (IOException e) {
            }
        }

# 二．获取压缩文件里某一个文件的数据 #

//扫描压缩文件里面的某一个文件的数据，传人的是压缩文件的决定路径和里面的某一个文件的名称
    
        public void scanZipFile(String zipname, String name) {
            Log.e("TAG", "scanZipFile");
            try {
                ZipInputStream zin = new ZipInputStream(
                        new FileInputStream(zipname));
                ZipEntry entry;
               while ((entry = zin.getNextEntry()) != null) {
                    if (entry.getName().equals(name)) {
                StringBuffer stringBuffer = new StringBuffer();
    
                        int len = 0;
                        byte[] buf = new byte[1024];
                        while ((len = zin .read(buf)) != -1) {
                            stringBuffer.append(new String(buf, 0, len));
                        }
                        Log.e("TAG", "stringBuffer:" + stringBuffer);
                     }
                    zin.closeEntry();
                }
                zin.close();
            } catch (IOException e) {
                Log.e("TAG", e.getMessage());
            }

# 三．解压文件的代码 #

/*
       * 这个是解压ZIP格式文件的方法
       *
       * @zipFileName：是传进来你要解压的文件路径，包括文件的名字；
       *
       * @outputDirectory:选择你要保存的路劲；
       *
       */
        public  static void  unzip(String zipFileName, String outputDirectory)
                throws Exception {
            ZipInputStream in = new ZipInputStream(new FileInputStream(zipFileName));
    
            Log.e("TAG", "in==null"+(in==null));
    
            ZipEntry z;
            String name = "";
            String extractedFile = "";
            int counter = 0;
    
            while ((z = in.getNextEntry()) != null) {
                name = z.getName();
                Log.d("TAG", "unzipping file: " + name);
                if (z.isDirectory()) {
                    Log.d("TAG", name + "is a folder");
                    // get the folder name of the widget  
                    name = name.substring(0, name.length() - 1);
                    File folder = new File(outputDirectory + File.separator + name);
                    folder.mkdirs();
                    if (counter == 0) {
                        extractedFile = folder.toString();
                    }
                    counter++;
                    Log.d("TAG", "mkdir " + outputDirectory + File.separator + name);
                } else {
                    Log.d("TAG", name + "is a normal file");
                    File file = new File(outputDirectory + File.separator + name);
                    file.createNewFile();
                    // get the output stream of the file  
                    FileOutputStream out = new FileOutputStream(file);
                    int ch;
                    byte[] buffer = new byte[1024];
                    // read (ch) bytes into buffer  
                    while ((ch = in.read(buffer)) != -1) {
                        // write (ch) byte from buffer at the position 0  
                        out.write(buffer, 0, ch);
                        out.flush();
                    }
                    out.close();
                }
            }
    
            in.close();
    
        }

上面三个方法都是测试成功的。失败的话只能是路径不对或没添加权限。  
但是第三个方法好像不能解压大文件，  
如果是大文件可以使用下面的方法：

# 四.解压大文件的代码 #

/**
         * 2     * 解压缩功能.
         * 3     * 将zipFile文件解压到folderPath目录下.
         * 4     * @throws Exception
         * 5
         */
        public static boolean upZipFile(File zipFile, String folderPath) throws ZipException, IOException {
            //public static void upZipFile() throws Exception{
        
            ZipFile zfile = new ZipFile(zipFile);
            Enumeration zList = zfile.entries();
            ZipEntry ze = null;
            byte[] buf = new byte[1024];
            while (zList.hasMoreElements()) {
                ze = (ZipEntry) zList.nextElement();
                if (ze.isDirectory()) {
                    Log.d("upZipFile", "ze.getName() = " + ze.getName());
                    String dirstr = folderPath + ze.getName();
                    //dirstr.trim();
                    dirstr = new String(dirstr.getBytes("8859_1"), "GB2312");
                    Log.d("upZipFile", "str = " + dirstr);
                    File f = new File(dirstr);
                    f.mkdir();
                    continue;
                }
                Log.d("upZipFile", "ze.getName() = " + ze.getName());
                OutputStream os = new BufferedOutputStream(new FileOutputStream(getRealFileName(folderPath, ze.getName())));
                InputStream is = new BufferedInputStream(zfile.getInputStream(ze));
                int readLen = 0;
                while ((readLen = is.read(buf, 0, 1024)) != -1) {
                    os.write(buf, 0, readLen);
                    Log.d("upZipFile", "writing");
                }
                is.close();
                os.close();
            }
            zfile.close();
            Log.d("upZipFile", "finish");
            return true;
        }
    
        public static File getRealFileName(String baseDir, String absFileName) {
            String[] dirs = absFileName.split("/");
            String lastDir = baseDir;
            if (dirs.length > 1) {
                for (int i = 0; i < dirs.length - 1; i++) {
                    lastDir += (dirs[i] + "/");
                    File dir = new File(lastDir);
                    if (!dir.exists()) {
                        dir.mkdirs();
                        Log.d("getRealFileName", "create dir = " + (lastDir + "/" + dirs[i]));
                    }
                }
                File ret = new File(lastDir, dirs[dirs.length - 1]);
                Log.d("upZipFile", "2ret = " + ret);
                return ret;
            } else {
                return new File(baseDir, absFileName);
            }
    
        }

上面这段代码是可以解压几百兆的压缩文件的，已经试过了。  
要添加权限：

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