Case study of decompressing and compressing folders in Java

This article mainly introduces the relevant information of Java decompression and compressed folder examples. I hope this article can help everyone to realize such functions and master such methods. Friends in need can refer to it

Detailed examples of java decompression and compression folders

Note: JDK7 supports setting encoding and encoding format zipFile, zipInputStream, and zipOutputStream have added encoding formats , if jdk1.6 needs other package assistance

The following is the code for the built-in jdk compressed folder:

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public void dozip(String srcfile, String zipfile) throws IOException {
  String temp = "";
  File src = new File(srcfile);
  File zipFile=new File(zipfile);
  //判断要压缩的文件存不存在
  if (!src.exists()) {
    System.err.println("要压缩的文件不存在！");
    System.exit(1);
  }
  //如果说压缩路径不存在，则创建
  if (!zipFile.getParentFile().exists()) {
    zipFile.getParentFile().mkdirs();
//   System.out.println("创建ok");
  }
  // 封装压缩的路径
  BufferedOutputStream bos=new BufferedOutputStream(new FileOutputStream(zipfile));
  //这里可以加入校验
//CheckedOutputStream cos = new CheckedOutputStream(bos,new CRC32());  
  //还可以设置压缩格式，默认UTF-8
  Charset charset = Charset.forName("GBK"); 
  ZipOutputStream zos = new ZipOutputStream(bos,charset);
  zip(src, zos, temp);
  //关闭流
  zos.flush();
  zos.close();
  System.out.println("压缩完成！");
  System.out.println("压缩文件的位置是：" + zipfile);
// System.out.println("检验和："+cos.getChecksum().getValue());
  }

 private void zip(File file, ZipOutputStream zos, String temp)
    throws IOException {
  // 如果不加"/"将会作为文件处理，空文件夹不需要读写操作
  if (file.isDirectory()) {
    String str = temp + file.getName() + "/";
    zos.putNextEntry(new ZipEntry(str));
    File[] files = file.listFiles();
    for (File file2 : files) {
    zip(file2, zos, str);
    }
  } else {
    // System.out.println("当前文件的父路径："+temp);
    ZipFile(file, zos, temp);
  }
  }

  private void ZipFile(File srcfile, ZipOutputStream zos, String temp)
    throws IOException {
  // 默认的等级压缩-1
  // zos.setLevel(xxx);
  // 封装待压缩文件
  BufferedInputStream bis = new BufferedInputStream(new FileInputStream(
    srcfile));
  zos.putNextEntry(new ZipEntry(temp + srcfile.getName()));

  byte buf[] = new byte[1024];
  int len;
  while ((len = bis.read(buf)) != -1) {
    zos.write(buf, 0, len);
  }
  //按标准需要关闭当前条目，不写也行
  zos.closeEntry();
  bis.close();
  }

The following is the decompression:

Here are the decompression rules for good compression:

1. If you decompress to a folder with the same name as the compressed file, decompress directly

If you have customized other folder xxx, create xxx first, and then put it into the decompressed folder

2. When Haoyi compresses, it uses the GBK format, so when decompressing , for the sake of unification, GBK decompression is used. Let’s talk about WINRAR. Because RAR compression is patented (commercial software), the RAR compression algorithm is not public, but the decompression algorithm is available, and its compression is also in GBK format by default;

After testing, we found that no matter whether UTF-8 or GBK is used for compression, GBK can be used for decompression correctly! (The specific reason is still unclear)

This java program is decompressed directly to the folder. By default, it is decompressed to the same path as the compressed file.

If there is a problem with the decompression encoding, an error will be reported: java.lang.IllegalArgumentException: MALFORMED

If the compressed file has a password: Error: java.util.zip.ZipException: encrypted ZIP entry not supporte

//方法1：
public void unZip(String zipfile) throws IOException {
  //检查是否是zip文件,并判断文件是否存在
  checkFileName(zipfile);
  long startTime = System.currentTimeMillis();
  File zfile=new File(zipfile);
  //获取待解压文件的父路径
  String Parent=zfile.getParent()+"/";
  FileInputStream fis=new FileInputStream(zfile);
  Charset charset = Charset.forName("GBK");//默认UTF-8
// CheckedInputStream cis = new CheckedInputStream(fis,new CRC32());
  ZipInputStream zis = new ZipInputStream(fis,charset);// 输入源zip路径
  ZipEntry entry=null;
  BufferedOutputStream bos=null;
  while ((entry=zis.getNextEntry())!=null) {
    if (entry.isDirectory()) {
    File filePath=new File(Parent+entry.getName());
    //如果目录不存在，则创建
    if (!filePath.exists()) {
      filePath.mkdirs();
    }
    }else{
    FileOutputStream fos=new FileOutputStream(Parent+entry.getName());
    bos=new BufferedOutputStream(fos);
    byte buf[] = new byte[1024];
    int len;
    while ((len = zis.read(buf)) != -1) {
      bos.write(buf, 0, len);
    }
    zis.closeEntry();
    //关闭的时候会刷新
    bos.close();
    }
  }
  zis.close();
  long endTime = System.currentTimeMillis();
  System.out.println("解压完成！所需时间为："+(endTime-startTime)+"ms");
// System.out.println("校验和："+cis.getChecksum().getValue());
  }

  private void checkFileName(String name) {
  //文件是否存在
  if (!new File(name).exists()) {
    System.err.println("要解压的文件不存在！");
    System.exit(1);
  }
  // 判断是否是zip文件
  int index = name.lastIndexOf(".");
  String str=name.substring(index+1);
  if (!"zip".equalsIgnoreCase(str)) {
    System.err.println("不是zip文件,无法解压！");
    System.exit(1);
  } 
    }

Method 2:

Use zipFile to decompress. The method is similar to ZipInputStream. Entry is obtained continuously, and then Entry is used to judge. I heard that zipFile has a built-in buffer stream, so for the same The efficiency of decompressing a file multiple times is higher than ZipInputStream

 public void dozip(String zipfile) throws IOException {
  checkFileName(zipfile);
  long startTime = System.currentTimeMillis();
  // 获取待解压文件的父路径
  File zfile = new File(zipfile);
  String Parent = zfile.getParent() + "/";
  // 设置,默认是UTF-8
  Charset charset = Charset.forName("GBK");
  ZipFile zip = new ZipFile(zipfile, charset);
  ZipEntry entry = null;
  //封装解压后的路径
  BufferedOutputStream bos=null;
  //封装待解压文件路径
  BufferedInputStream bis=null;
  Enumeration<ZipEntry> enums = (Enumeration<ZipEntry>) zip.entries();
  while (enums.hasMoreElements()) {
    entry = enums.nextElement();
    if (entry.isDirectory()) {
    File filePath = new File(Parent + entry.getName());
    // 如果目录不存在，则创建
    if (!filePath.exists()) {
      filePath.mkdirs();
    }
    }else{
    bos=new BufferedOutputStream(new FileOutputStream(Parent + entry.getName()));
    //获取条目流
bis =new BufferedInputStream(zip.getInputStream(entry));
    byte buf[] = new byte[1024];
    int len;
    while ((len = bis.read(buf)) != -1) {
      bos.write(buf, 0, len);
    }

    bos.close();
    }
  }
  bis.close();
  zip.close();
  System.out.println("解压后的路径是："+Parent);
  long endTime = System.currentTimeMillis();
  System.out.println("解压成功,所需时间为:"+(endTime-startTime)+"ms");
  }

  private void checkFileName(String name) {
  // 文件是否存在
  if (!new File(name).exists()) {
    System.err.println("要解压的文件不存在！");
    System.exit(1);
  }
  // 判断是否是zip文件
  int index = name.lastIndexOf(".");
  String str = name.substring(index + 1);
  if (!"zip".equalsIgnoreCase(str)) {
    System.err.println("不是zip文件,无法解压！");
    System.exit(1);
  }
  }

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